V$latch_children
Hello
in V$latch_children we have latch# as well as child#. Latch# is the parent latch of the child. Does it mean that latch# is the holder of the latch? And child# is waiting for latch?
Rgds
Hi,
Latch# is the latch number for parent latch and child# is the number for child latch. Child latch is not the one that is waiting for the latch. Parent latch have its child latches which further performs their task. To know little about child latches please go through the below link:-
http://learningoracle.wordpress.com/2008/02/19/latches-and-latch-contention/
To know about V$LATCH_CHILDREN go through the below link:-
http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/dynviews_1137.htm
Regards
Similar Messages
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Package.......StatsPack...Error..
Hi.. i m tuning my Oracle Database, for that i need to install Statspack package, when i compiled package... it returned following error.
Warning: Package Body created with compilation errors.
SQL> show error
Errors for PACKAGE BODY STATSPACK:
LINE/COL ERROR
2045/3 PLS-00201: identifier 'SYS.DBMS_SHARED_POOL' must be declared
2045/3 PL/SQL: Statement ignored
HOw to solve above error..Please check the following Package, and do help me.
Note: I m connected perfstat user, no as SYS user.
create or replace package body STATSPACK as
/* Define package variables.
Variables prefixed with p_ are package variables.
p_snap_id integer; /* snapshot id */
p_instance_number number; /* instance number */
p_instance_name varchar2(16); /* instance name */
p_startup_time date; /* instance startup time */
p_parallel varchar2(3); /* parallel server */
p_version varchar2(17); /* Oracle release */
p_dbid number; /* database id */
p_host_name varchar2(64); /* host instance is on */
p_name varchar2(9); /* database name */
p_new_sga integer; /* Instance bounced since last snap? */
tmp_int integer; /* initialise defaults */
p_def_snap_level number default 5; /* default snapshot lvl */
p_def_session_id number default 0; /* default session id */
p_def_ucomment varchar2(160) default null;
p_def_pin_statspack varchar2(10) default 'TRUE';
p_def_last_modified date default SYSDATE;
/* Below are the default threshold (_th) values for choosing SQL statements
to store in the stats$sqlsummary table - these statements will typically
be the statements using the most resources.
p_def_num_sql number default 50; /* Num. SQL statements */
p_def_executions_th number default 100; /* Num. executions */
p_def_parse_calls_th number default 1000; /* Num. parse calls */
p_def_disk_reads_th number default 1000; /* Num. disk reads */
p_def_buffer_gets_th number default 10000; /* Num. buf gets */
p_def_sharable_mem_th number default 1048576; /* Sharable memory */
p_def_version_count_th number default 20; /* Child Cursors */
p_def_all_init varchar2(10) default 'FALSE';
cursor get_instance is
select instance_number, instance_name
, startup_time, parallel, version
, host_name
from v$instance;
cursor get_db is
select dbid, name
from v$database;
procedure SNAP
(i_snap_level in number default null
,i_session_id in number default null
,i_ucomment in varchar2 default null
,i_num_sql in number default null
,i_executions_th in number default null
,i_parse_calls_th in number default null
,i_disk_reads_th in number default null
,i_buffer_gets_th in number default null
,i_sharable_mem_th in number default null
,i_version_count_th in number default null
,i_all_init in varchar2 default null
,i_pin_statspack in varchar2 default null
,i_modify_parameter in varchar2 default 'FALSE'
is
/* Takes a snapshot by calling the SNAP function, and discards
the snapshot id. This is useful when automating taking
snapshots from dbms_job
l_snap_id number;
begin
l_snap_id := statspack.snap ( i_snap_level, i_session_id, i_ucomment
, i_num_sql
, i_executions_th
, i_parse_calls_th
, i_disk_reads_th
, i_buffer_gets_th
, i_sharable_mem_th
, i_version_count_th
, i_all_init
, i_pin_statspack
, i_modify_parameter);
end SNAP;
procedure MODIFY_STATSPACK_PARAMETER
( i_dbid in number default null
, i_instance_number in number default null
, i_snap_level in number default null
, i_session_id in number default null
, i_ucomment in varchar2 default null
, i_num_sql in number default null
, i_executions_th in number default null
, i_parse_calls_th in number default null
, i_disk_reads_th in number default null
, i_buffer_gets_th in number default null
, i_sharable_mem_th in number default null
, i_version_count_th in number default null
, i_all_init in varchar2 default null
, i_pin_statspack in varchar2 default null
, i_modify_parameter in varchar2 default 'TRUE'
is
/* Calls QAM with the modify flag, and discards the
output variables
l_snap_level number;
l_session_id number;
l_ucomment varchar2(160);
l_num_sql number;
l_executions_th number;
l_parse_calls_th number;
l_disk_reads_th number;
l_buffer_gets_th number;
l_sharable_mem_th number;
l_version_count_th number;
l_all_init varchar2(5);
l_pin_statspack varchar2(10);
begin
statspack.qam_statspack_parameter( i_dbid
, i_instance_number
, i_snap_level
, i_session_id
, i_ucomment
, i_num_sql
, i_executions_th
, i_parse_calls_th
, i_disk_reads_th
, i_buffer_gets_th
, i_sharable_mem_th
, i_version_count_th
, i_all_init
, i_pin_statspack
, 'TRUE'
, l_snap_level
, l_session_id
, l_ucomment
, l_num_sql
, l_executions_th
, l_parse_calls_th
, l_disk_reads_th
, l_buffer_gets_th
, l_sharable_mem_th
, l_version_count_th
, l_all_init
, l_pin_statspack);
/* As we have explicity been requested to change the parameters,
independently of taking a snapshot, commit
commit;
end MODIFY_STATSPACK_PARAMETER;
procedure QAM_STATSPACK_PARAMETER
( i_dbid in number default null
, i_instance_number in number default null
, i_snap_level in number default null
, i_session_id in number default null
, i_ucomment in varchar2 default null
, i_num_sql in number default null
, i_executions_th in number default null
, i_parse_calls_th in number default null
, i_disk_reads_th in number default null
, i_buffer_gets_th in number default null
, i_sharable_mem_th in number default null
, i_version_count_th in number default null
, i_all_init in varchar2 default null
, i_pin_statspack in varchar2 default null
, i_modify_parameter in varchar2 default 'FALSE'
, o_snap_level out number
, o_session_id out number
, o_ucomment out varchar2
, o_num_sql out number
, o_executions_th out number
, o_parse_calls_th out number
, o_disk_reads_th out number
, o_buffer_gets_th out number
, o_sharable_mem_th out number
, o_version_count_th out number
, o_all_init out varchar2
, o_pin_statspack out varchar2
is
/* Query And Modify statspack parameter procedure, allows query
and/or user modification of the statistics collection parameters
for an instance. If there are no pre-existing parameters for
an instance, insert the Oracle defaults.
l_instance_number number;
l_dbid number;
ui_all_init varchar2(5);
l_params_exist varchar2(1);
begin
if ((i_dbid is null ) or (i_instance_number is null)) then
l_dbid := p_dbid;
l_instance_number := p_instance_number;
else
l_dbid := i_dbid;
l_instance_number := i_instance_number;
end if;
/* Upper case any input vars which are inserted */
ui_all_init := upper(i_all_init);
if ( (i_modify_parameter is null)
or (upper(i_modify_parameter) = 'FALSE') ) then
/* Query values, if none exist, insert the defaults tempered
with variables supplied */
begin
select nvl(i_session_id, session_id)
, nvl(i_snap_level, snap_level)
, nvl(i_ucomment, ucomment)
, nvl(i_num_sql, num_sql)
, nvl(i_executions_th, executions_th)
, nvl(i_parse_calls_th, parse_calls_th)
, nvl(i_disk_reads_th, disk_reads_th)
, nvl(i_buffer_gets_th, buffer_gets_th)
, nvl(i_sharable_mem_th, sharable_mem_th)
, nvl(i_version_count_th, version_count_th)
, nvl(ui_all_init, all_init)
, nvl(i_pin_statspack, pin_statspack)
into o_session_id
, o_snap_level
, o_ucomment
, o_num_sql
, o_executions_th
, o_parse_calls_th
, o_disk_reads_th
, o_buffer_gets_th
, o_sharable_mem_th
, o_version_count_th
, o_all_init
, o_pin_statspack
from stats$statspack_parameter
where instance_number = l_instance_number
and dbid = l_dbid;
exception
when NO_DATA_FOUND then
insert into stats$statspack_parameter
( dbid
, instance_number
, session_id
, snap_level
, ucomment
, num_sql
, executions_th
, parse_calls_th
, disk_reads_th
, buffer_gets_th
, sharable_mem_th
, version_count_th
, all_init
, pin_statspack
, last_modified
values
( l_dbid
, l_instance_number
, p_def_session_id
, p_def_snap_level
, p_def_ucomment
, p_def_num_sql
, p_def_executions_th
, p_def_parse_calls_th
, p_def_disk_reads_th
, p_def_buffer_gets_th
, p_def_sharable_mem_th
, p_def_version_count_th
, p_def_all_init
, p_def_pin_statspack
, SYSDATE
returning nvl(i_session_id, p_def_session_id)
, nvl(i_snap_level, p_def_snap_level)
, nvl(i_ucomment, p_def_ucomment)
, nvl(i_num_sql, p_def_num_sql)
, nvl(i_executions_th, p_def_executions_th)
, nvl(i_parse_calls_th, p_def_parse_calls_th)
, nvl(i_disk_reads_th, p_def_disk_reads_th)
, nvl(i_buffer_gets_th, p_def_buffer_gets_th)
, nvl(i_sharable_mem_th, p_def_sharable_mem_th)
, nvl(i_version_count_th, p_def_version_count_th)
, nvl(ui_all_init, p_def_all_init)
, nvl(i_pin_statspack, p_def_pin_statspack)
into o_session_id
, o_snap_level
, o_ucomment
, o_num_sql
, o_executions_th
, o_parse_calls_th
, o_disk_reads_th
, o_buffer_gets_th
, o_sharable_mem_th
, o_version_count_th
, o_all_init
, o_pin_statspack;
end; /* don't modify parameter values */
elsif upper(i_modify_parameter) = 'TRUE' then
/* modify values, if none exist, insert the defaults tempered
with the variables supplied */
begin
update stats$statspack_parameter
set session_id = nvl(i_session_id, session_id)
, snap_level = nvl(i_snap_level, snap_level)
, ucomment = nvl(i_ucomment, ucomment)
, num_sql = nvl(i_num_sql, num_sql)
, executions_th = nvl(i_executions_th, executions_th)
, parse_calls_th = nvl(i_parse_calls_th, parse_calls_th)
, disk_reads_th = nvl(i_disk_reads_th, disk_reads_th)
, buffer_gets_th = nvl(i_buffer_gets_th, buffer_gets_th)
, sharable_mem_th = nvl(i_sharable_mem_th, sharable_mem_th)
, version_count_th = nvl(i_version_count_th, version_count_th)
, all_init = nvl(ui_all_init, all_init)
, pin_statspack = nvl(i_pin_statspack, pin_statspack)
where instance_number = l_instance_number
and dbid = l_dbid
returning session_id
, snap_level
, ucomment
, num_sql
, executions_th
, parse_calls_th
, disk_reads_th
, buffer_gets_th
, sharable_mem_th
, version_count_th
, all_init
, pin_statspack
into o_session_id
, o_snap_level
, o_ucomment
, o_num_sql
, o_executions_th
, o_parse_calls_th
, o_disk_reads_th
, o_buffer_gets_th
, o_sharable_mem_th
, o_version_count_th
, o_all_init
, o_pin_statspack;
if SQL%ROWCOUNT = 0 then
insert into stats$statspack_parameter
( dbid
, instance_number
, session_id
, snap_level
, ucomment
, num_sql
, executions_th
, parse_calls_th
, disk_reads_th
, buffer_gets_th
, sharable_mem_th
, version_count_th
, all_init
, pin_statspack
, last_modified
values
( l_dbid
, l_instance_number
, nvl(i_session_id, p_def_session_id)
, nvl(i_snap_level, p_def_snap_level)
, nvl(i_ucomment, p_def_ucomment)
, nvl(i_num_sql, p_def_num_sql)
, nvl(i_executions_th, p_def_executions_th)
, nvl(i_parse_calls_th, p_def_parse_calls_th)
, nvl(i_disk_reads_th, p_def_disk_reads_th)
, nvl(i_buffer_gets_th, p_def_buffer_gets_th)
, nvl(i_sharable_mem_th, p_def_sharable_mem_th)
, nvl(i_version_count_th, p_def_version_count_th)
, nvl(ui_all_init, p_def_all_init)
, nvl(i_pin_statspack, p_def_pin_statspack)
, SYSDATE
returning session_id
, snap_level
, ucomment
, num_sql
, executions_th
, parse_calls_th
, disk_reads_th
, buffer_gets_th
, sharable_mem_th
, version_count_th
, all_init
, pin_statspack
into o_session_id
, o_snap_level
, o_ucomment
, o_num_sql
, o_executions_th
, o_parse_calls_th
, o_disk_reads_th
, o_buffer_gets_th
, o_sharable_mem_th
, o_version_count_th
, o_all_init
, o_pin_statspack;
end if;
end; /* modify values */
else
/* error */
raise_application_error
(-20100,'QAM_STATSPACK_PARAMETER i_modify_parameter value is invalid');
end if; /* modify */
end QAM_STATSPACK_PARAMETER;
procedure STAT_CHANGES
/* Returns a set of differences of the values from corresponding pairs
of rows in STATS$SYSSTAT, STATS$LIBRARYCACHE and STATS$WAITSTAT,
based on the begin and end (bid, eid) snapshot id's specified.
This procedure is the only call to STATSPACK made by the statsrep
report.
Modified to include multi-db support.
( bid IN number
, eid IN number
, db_ident IN number
, inst_num IN number
, parallel IN varchar2
, lhtr OUT number, bfwt OUT number
, tran OUT number, chng OUT number
, ucal OUT number, urol OUT number
, rsiz OUT number
, phyr OUT number, phyrd OUT number
, phyrdl OUT number
, phyw OUT number, ucom OUT number
, prse OUT number, hprse OUT number
, recr OUT number, gets OUT number
, rlsr OUT number, rent OUT number
, srtm OUT number, srtd OUT number
, srtr OUT number, strn OUT number
, lhr OUT number, bc OUT varchar2
, sp OUT varchar2, lb OUT varchar2
, bs OUT varchar2, twt OUT number
, logc OUT number, prscpu OUT number
, tcpu OUT number, exe OUT number
, prsela OUT number
, bspm OUT number, espm OUT number
, bfrm OUT number, efrm OUT number
, blog OUT number, elog OUT number
, bocur OUT number, eocur OUT number
, dmsd OUT number, dmfc OUT number -- begin OPS
, dfcms OUT number, dfcmr OUT number
, dmsi OUT number, dmrv OUT number
, dynal OUT number, dynares OUT number
, pmrv OUT number, pmpt OUT number
, npmrv OUT number, npmpt OUT number
, scma OUT number, scml OUT number
, pinc OUT number, picrnc OUT number
, picc OUT number, picrcc OUT number
, pbc OUT number, pbcrc OUT number
, pcba OUT number, pccrba OUT number
, pcrbpi OUT number
, dynapres OUT number, dynapshl OUT number
, prcma OUT number, prcml OUT number
, pwrm OUT number, pfpim OUT number
, pwnm OUT number
, dpms OUT number, dnpms OUT number
, glsg OUT number, glag OUT number
, glgt OUT number, glsc OUT number
, glac OUT number, glct OUT number
, glrl OUT number
, gcge OUT number, gcgt OUT number
, gccv OUT number, gcct OUT number
, gccrrv OUT number, gccrrt OUT number
, gccurv OUT number, gccurt OUT number
, gccrsv OUT number
, gccrbt OUT number, gccrft OUT number
, gccrst OUT number, gccusv OUT number
, gccupt OUT number, gccuft OUT number
, gccust OUT number -- end OPS
) is
bval number;
eval number;
l_b_session_id number; /* begin session id */
l_b_serial# number; /* begin serial# */
l_e_session_id number; /* end session id */
l_e_serial# number; /* end serial# */
function LIBRARYCACHE_HITRATIO RETURN number is
/* Returns Library cache hit ratio for the begin and end (bid, eid)
snapshot id's specified
cursor LH (i_snap_id number) is
select sum(pins), sum(pinhits)
from stats$librarycache
where snap_id = i_snap_id
and dbid = db_ident
and instance_number = inst_num;
bpsum number;
bhsum number;
epsum number;
ehsum number;
begin
if not LH%ISOPEN then open LH (bid); end if;
fetch LH into bpsum, bhsum;
if LH%NOTFOUND then
raise_application_error
(-20100,'Missing start value for stats$librarycache');
end if; close LH;
if not LH%ISOPEN then open LH (eid); end if;
fetch LH into epsum, ehsum;
if LH%NOTFOUND then
raise_application_error
(-20100,'Missing end value for stats$librarycache');
end if; close LH;
return (ehsum - bhsum) / (epsum - bpsum);
end LIBRARYCACHE_HITRATIO;
function GET_PARAM (i_name varchar2) RETURN varchar2 is
/* Returns the value for the init.ora parameter for the snapshot
specified.
cursor PARAMETER is
select value
from stats$parameter
where snap_id = eid
and dbid = db_ident
and instance_number = inst_num
and name = i_name;
par_value varchar2(512);
begin
if not PARAMETER%ISOPEN then open PARAMETER; end if;
fetch PARAMETER into par_value;
if PARAMETER%NOTFOUND then
raise_application_error
(-20100,'Missing Init.ora parameter '|| i_name);
end if; close PARAMETER;
return par_value;
end GET_PARAM;
function GET_SYSSTAT (i_name varchar2, i_beid number) RETURN number is
/* Returns the value for the System Statistic for the snapshot
specified.
cursor SYSSTAT is
select value
from stats$sysstat
where snap_id = i_beid
and dbid = db_ident
and instance_number = inst_num
and name = i_name;
stat_value varchar2(512);
begin
if not SYSSTAT%ISOPEN then open SYSSTAT; end if;
fetch SYSSTAT into stat_value;
if SYSSTAT%NOTFOUND then
raise_application_error
(-20100,'Missing System Statistic '|| i_name);
end if; close SYSSTAT;
return stat_value;
end GET_SYSSTAT;
function BUFFER_WAITS RETURN number is
/* Returns the total number of waits for all buffers in the interval
specified by the begin and end snapshot id's (bid, eid)
cursor BW (i_snap_id number) is
select sum(wait_count)
from stats$waitstat
where snap_id = i_snap_id
and dbid = db_ident
and instance_number = inst_num;
bbwsum number; ebwsum number;
begin
if not BW%ISOPEN then open BW (bid); end if;
fetch BW into bbwsum;
if BW%NOTFOUND then
raise_application_error
(-20100,'Missing start value for stats$waitstat');
end if; close BW;
if not BW%ISOPEN then open BW (eid); end if;
fetch BW into ebwsum;
if BW%NOTFOUND then
raise_application_error
(-20100,'Missing end value for stats$waitstat');
end if; close BW;
return ebwsum - bbwsum;
end BUFFER_WAITS;
function TOTAL_EVENT_TIME RETURN number is
/* Returns the total amount of time waited for events for
the interval specified by the begin and end snapshot id's
(bid, eid) by foreground processes. This excludes idle
wait events.
cursor WAITS (i_snap_id number) is
select sum(time_waited_micro)
from stats$system_event
where snap_id = i_snap_id
and dbid = db_ident
and instance_number = inst_num
and event not in (select event from stats$idle_event);
bwaittime number;
ewaittime number;
begin
if not WAITS%ISOPEN then open WAITS (bid); end if;
fetch WAITS into bwaittime;
if WAITS%NOTFOUND then
raise_application_error
(-20100,'Missing start value for stats$system_event');
end if; close WAITS;
if not WAITS%ISOPEN then open WAITS (eid); end if;
fetch WAITS into ewaittime;
if WAITS%NOTFOUND then
raise_application_error
(-20100,'Missing end value for stats$system_event');
end if; close WAITS;
return ewaittime - bwaittime;
end TOTAL_EVENT_TIME;
function LATCH_HITRATIO return NUMBER is
/* Returns the latch hit ratio specified by the begin and
end snapshot id's (bid, eid)
cursor GETS_MISSES (i_snap_id number) is
select sum(gets), sum(misses)
from stats$latch
where snap_id = i_snap_id
and dbid = db_ident
and instance_number = inst_num;
blget number; -- beginning latch gets
blmis number; -- beginning latch misses
elget number; -- end latch gets
elmis number; -- end latch misses
begin
if not GETS_MISSES%ISOPEN then open GETS_MISSES (bid); end if;
fetch GETS_MISSES into blget, blmis;
if GETS_MISSES%NOTFOUND then
raise_application_error
(-20100,'Missing start value for STATS$LATCH gets and misses');
end if; close GETS_MISSES;
if not GETS_MISSES%ISOPEN then open GETS_MISSES (eid); end if;
fetch GETS_MISSES into elget, elmis;
if GETS_MISSES%NOTFOUND then
raise_application_error
(-20100,'Missing end value for STATS$LATCH gets and misses');
end if; close GETS_MISSES;
return ( ( elmis - blmis ) / ( elget - blget ) );
end LATCH_HITRATIO;
function SGASTAT (i_name varchar2, i_beid number) RETURN number is
/* Returns the bytes used by i_name in the shared pool
for the begin or end snapshot (bid, eid) specified
cursor bytes_used is
select bytes
from stats$sgastat
where snap_id = i_beid
and dbid = db_ident
and instance_number = inst_num
and pool in ('shared pool', 'all pools')
and name = i_name;
total_bytes number;
begin
if i_name = 'total_shared_pool' then
select sum(bytes)
into total_bytes
from stats$sgastat
where snap_id = i_beid
and dbid = db_ident
and instance_number = inst_num
and pool in ('shared pool','all pools');
else
open bytes_used; fetch bytes_used into total_bytes;
if bytes_used%notfound then
raise_application_error
(-20100,'Missing value for SGASTAT: '||i_name);
end if;
close bytes_used;
end if;
return total_bytes;
end SGASTAT;
function SYSDIF (i_name varchar2) RETURN number is
/* Returns the difference between statistics for the statistic
name specified for the interval between the begin and end
snapshot id's (bid, eid)
cursor SY (i_snap_id number) is
select value
from stats$sysstat
where snap_id = i_snap_id
and dbid = db_ident
and instance_number = inst_num
and name = i_name;
begin
/* Get start value */
open SY (bid); fetch SY into bval;
if SY%notfound then
raise_application_error
(-20100,'Missing start value for statistic: '||i_name);
end if; close SY;
/* Get end value */
open SY (eid); fetch SY into eval;
if SY%notfound then
raise_application_error
(-20100,'Missing end value for statistic: '||i_name);
end if; close SY;
/* Return difference */
return eval - bval;
end SYSDIF;
function SESDIF (st_name varchar2) RETURN number is
/* Returns the difference between statistics values for the
statistic name specified for the interval between the begin and end
snapshot id's (bid, eid), for the session monitored for that
snapshot
cursor SE (i_snap_id number) is
select ses.value
from stats$sysstat sys
, stats$sesstat ses
where sys.snap_id = i_snap_id
and ses.snap_id = i_snap_id
and ses.dbid = db_ident
and sys.dbid = db_ident
and ses.instance_number = inst_num
and sys.instance_number = inst_num
and ses.statistic# = sys.statistic#
and sys.name = st_name;
begin
/* Get start value */
open SE (bid); fetch SE into bval;
if SE%notfound then
eval :=0;
end if; close SE;
/* Get end value */
open SE (eid); fetch SE into eval;
if SE%notfound then
eval :=0;
end if; close SE;
/* Return difference */
return eval - bval;
end SESDIF;
function DLMDIF (i_name varchar2) RETURN number is
/* Returns the difference between statistics for the statistic
name specified for the interval between the begin and end
snapshot id's (bid, eid)
cursor DLM (i_snap_id number) is
select value
from stats$dlm_misc
where snap_id = i_snap_id
and dbid = db_ident
and instance_number = inst_num
and name = i_name;
begin
/* Get start value */
open DLM (bid); fetch DLM into bval;
if DLM%notfound then
raise_application_error
(-20100,'Missing start value for statistic: '||i_name);
end if; close DLM;
/* Get end value */
open DLM (eid); fetch DLM into eval;
if DLM%notfound then
raise_application_error
(-20100,'Missing end value for statistic: '||i_name);
end if; close DLM;
/* Return difference */
return eval - bval;
end DLMDIF;
begin /* main procedure body of STAT_CHANGES */
lhtr := LIBRARYCACHE_HITRATIO;
bfwt := BUFFER_WAITS;
lhr := LATCH_HITRATIO;
chng := SYSDIF('db block changes');
ucal := SYSDIF('user calls');
urol := SYSDIF('user rollbacks');
ucom := SYSDIF('user commits');
tran := ucom + urol;
rsiz := SYSDIF('redo size');
phyr := SYSDIF('physical reads');
phyrd := SYSDIF('physical reads direct');
phyrdl := SYSDIF('physical reads direct (lob)');
phyw := SYSDIF('physical writes');
hprse := SYSDIF('parse count (hard)');
prse := SYSDIF('parse count (total)');
gets := SYSDIF('session logical reads');
recr := SYSDIF('recursive calls');
rlsr := SYSDIF('redo log space requests');
rent := SYSDIF('redo entries');
srtm := SYSDIF('sorts (memory)');
srtd := SYSDIF('sorts (disk)');
srtr := SYSDIF('sorts (rows)');
logc := SYSDIF('logons cumulative');
prscpu := SYSDIF('parse time cpu');
prsela := SYSDIF('parse time elapsed');
tcpu := SYSDIF('CPU used by this session');
exe := SYSDIF('execute count');
bs := GET_PARAM('db_block_size');
bc := GET_PARAM('db_block_buffers') * bs;
if bc = 0 then
bc := GET_PARAM('db_cache_size')
+ GET_PARAM('db_keep_cache_size')
+ GET_PARAM('db_recycle_cache_size')
+ GET_PARAM('db_2k_cache_size')
+ GET_PARAM('db_4k_cache_size')
+ GET_PARAM('db_8k_cache_size')
+ GET_PARAM('db_16k_cache_size')
+ GET_PARAM('db_32k_cache_size');
end if;
sp := GET_PARAM('shared_pool_size');
lb := GET_PARAM('log_buffer');
twt := TOTAL_EVENT_TIME; -- total wait time for all non-idle events
bspm := SGASTAT('total_shared_pool', bid);
espm := SGASTAT('total_shared_pool', eid);
bfrm := SGASTAT('free memory', bid);
efrm := SGASTAT('free memory', eid);
blog := GET_SYSSTAT('logons current', bid);
elog := GET_SYSSTAT('logons current', eid);
bocur := GET_SYSSTAT('opened cursors current', bid);
eocur := GET_SYSSTAT('opened cursors current', eid);
/* Do we want to report on cluster-specific statistics? Check
in procedure variable "parallel".
if parallel = 'YES' then
dmsd := DLMDIF('messages sent directly');
dmfc := DLMDIF('messages flow controlled');
dmsi := DLMDIF('messages sent indirectly');
dmrv := DLMDIF('messages received');
dfcms := DLMDIF('flow control messages sent');
dfcmr := DLMDIF('flow control messages received');
dynal := DLMDIF('dynamically allocated enqueues');
dynares := DLMDIF('dynamically allocated resources');
pmrv := DLMDIF('gcs msgs received');
pmpt := DLMDIF('gcs msgs process time(ms)');
npmrv := DLMDIF('ges msgs received');
npmpt := DLMDIF('ges msgs process time(ms)');
scma := DLMDIF('gcs side channel msgs actual');
scml := DLMDIF('gcs side channel msgs logical');
pinc := DLMDIF('gcs immediate (null) converts');
picrnc := DLMDIF('gcs immediate cr (null) converts');
picc := DLMDIF('gcs immediate (compatible) converts');
picrcc := DLMDIF('gcs immediate cr (compatible) converts');
pbc := DLMDIF('gcs blocked converts');
pbcrc := DLMDIF('gcs blocked cr converts');
pcba := DLMDIF('gcs compatible basts');
pccrba := DLMDIF('gcs compatible cr basts');
pcrbpi := DLMDIF('gcs cr basts to PIs');
dynapres := DLMDIF('dynamically allocated gcs resources');
dynapshl := DLMDIF('dynamically allocated gcs shadows');
prcma := DLMDIF('gcs recovery claim msgs actual');
prcml := DLMDIF('gcs recovery claim msgs logical');
pwrm := DLMDIF('gcs write request msgs');
pfpim := DLMDIF('gcs flush pi msgs');
pwnm := DLMDIF('gcs write notification msgs');
dpms := SYSDIF('gcs messages sent');
dnpms := SYSDIF('ges messages sent');
glsg := SYSDIF('global lock sync gets');
glag := SYSDIF('global lock async gets');
glgt := SYSDIF('global lock get time');
glsc := SYSDIF('global lock sync converts');
glac := SYSDIF('global lock async converts');
glct := SYSDIF('global lock convert time');
glrl := SYSDIF('global lock releases');
gcge := SYSDIF('global cache gets');
gcgt := SYSDIF('global cache get time');
gccv := SYSDIF('global cache converts');
gcct := SYSDIF('global cache convert time');
gccrrv := SYSDIF('global cache cr blocks received');
gccrrt := SYSDIF('global cache cr block receive time');
gccurv := SYSDIF('global cache current blocks received');
gccurt := SYSDIF('global cache current block receive time');
gccrsv := SYSDIF('global cache cr blocks served');
gccrbt := SYSDIF('global cache cr block build time');
gccrft := SYSDIF('global cache cr block flush time');
gccrst := SYSDIF('global cache cr block send time');
gccusv := SYSDIF('global cache current blocks served');
gccupt := SYSDIF('global cache current block pin time');
gccuft := SYSDIF('global cache current block flush time');
gccust := SYSDIF('global cache current block send time');
end if;
/* Determine if we want to report on session-specific statistics.
Check that the session is the same one for both snapshots.
select session_id
, serial#
into l_b_session_id
, l_b_serial#
from stats$snapshot
where snap_id = bid
and dbid = db_ident
and instance_number = inst_num;
select session_id
, serial#
into l_e_session_id
, l_e_serial#
from stats$snapshot
where snap_id = eid
and dbid = db_ident
and instance_number = inst_num;
if ( (l_b_session_id = l_e_session_id)
and (l_b_serial# = l_e_serial#)
and (l_b_session_id != 0) ) then
/* we have a valid comparison - it is the
same session - get number of tx performed
by this session */
strn := SESDIF('user rollbacks') + SESDIF('user commits');
if strn = 0 then
/* No new transactions */
strn := 1;
end if;
else
/* No valid comparison can be made */
strn :=1;
end if;
end STAT_CHANGES;
function SNAP
(i_snap_level in number default null
,i_session_id in number default null
,i_ucomment in varchar2 default null
,i_num_sql in number default null
,i_executions_th in number default null
,i_parse_calls_th in number default null
,i_disk_reads_th in number default null
,i_buffer_gets_th in number default null
,i_sharable_mem_th in number default null
,i_version_count_th in number default null
,i_all_init in varchar2 default null
,i_pin_statspack in varchar2 default null
,i_modify_parameter in varchar2 default 'FALSE'
RETURN integer IS
/* This function performs a snapshot of the v$ views into the
stats$ tables, and returns the snapshot id.
If parameters are passed, these are the values used, otherwise
the values stored in the stats$statspack_parameter table are used.
l_snap_id integer;
l_snap_level number;
l_session_id number;
l_serial# number;
l_ucomment varchar2(160);
l_num_sql number;
l_executions_th number;
l_parse_calls_th number;
l_disk_reads_th number;
l_buffer_gets_th number;
l_sharable_mem_th number;
l_version_count_th number;
l_all_init varchar2(5);
l_pin_statspack varchar2(10);
l_sql_stmt varchar2(3000);
l_slarti varchar2(20);
l_threshold number;
l_total_sql number := 0;
l_total_sql_mem number := 0;
l_single_use_sql number := 0;
l_single_use_sql_mem number := 0;
l_text_subset varchar2(31);
l_sharable_mem number;
l_version_count number;
l_sorts number;
l_module varchar2(64);
l_loaded_versions number;
l_executions number;
l_loads number;
l_invalidations number;
l_parse_calls number;
l_disk_reads number;
l_buffer_gets number;
l_rows_processed number;
l_address raw(8);
l_hash_value number;
l_version_count number;
l_max_begin_time date;
cursor GETSERIAL is
select serial#
from v$session
where sid = l_session_id;
PROCEDURE snap_sql IS
begin
/* Gather summary statistics */
insert into stats$sql_statistics
( snap_id
, dbid
, instance_number
, total_sql
, total_sql_mem
, single_use_sql
, single_use_sql_mem
select l_snap_id
, p_dbid
, p_instance_number
, count(1)
, sum(sharable_mem)
, sum(decode(executions, 1, 1, 0))
, sum(decode(executions, 1, sharable_mem, 0))
from stats$v$sqlxs
where is_obsolete = 'N';
/* Gather SQL statements which exceed any threshold,
excluding obsolete parent cursors
insert into stats$sql_summary
( snap_id
, dbid
, instance_number
, text_subset
, sharable_mem
, sorts
, module
, loaded_versions
, executions
, loads
, invalidations
, parse_calls
, disk_reads
, buffer_gets
, rows_processed
, command_type
, address
, hash_value
, version_count
, cpu_time
, elapsed_time
, outline_sid
, outline_category
select l_snap_id
, p_dbid
, p_instance_number
, substr(sql_text,1,31)
, sharable_mem
, sorts
, module
, loaded_versions
, executions
, loads
, invalidations
, parse_calls
, disk_reads
, buffer_gets
, rows_processed
, command_type
, address
, hash_value
, version_count
, cpu_time
, elapsed_time
, outline_sid
, outline_category
from stats$v$sqlxs
where is_obsolete = 'N'
and ( buffer_gets > l_buffer_gets_th
or disk_reads > l_disk_reads_th
or parse_calls > l_parse_calls_th
or executions > l_executions_th
or sharable_mem > l_sharable_mem_th
or version_count > l_version_count_th
/* Insert the SQL Text for hash_values captured in the snapshot
into stats$sqltext if it's not already there. Identify SQL which
execeeded the threshold by querying stats$sql_summary for this
snapid and database instance
insert into stats$sqltext
( hash_value
, text_subset
, piece
, sql_text
, address
, command_type
, last_snap_id
select st1.hash_value
, ss.text_subset
, st1.piece
, st1.sql_text
, st1.address
, st1.command_type
, ss.snap_id
from v$sqltext st1
, stats$sql_summary ss
where ss.snap_id = l_snap_id
and ss.dbid = p_dbid
and ss.instance_number = p_instance_number
and st1.hash_value = ss.hash_value
and st1.address = ss.address
and not exists (select 1
from stats$sqltext st2
where st2.hash_value = ss.hash_value
and st2.text_subset = ss.text_subset
IF l_snap_level >= 6 THEN
/* Identify SQL which execeeded the threshold by querying
stats$sql_summary for this snapid and database instance.
Capture the plans which were used for the high-load SQL if
don't already have this data.
Omit capturing plan usage information for cursors which
have a zero plan hash value.
Currently this is captured in a level 6 (or greater)
snapshot, however this may be integrated into level 5
snapshot at a later date.
hl - high load
insert into stats$sql_plan_usage
( hash_value
, text_subset
, plan_hash_value
, cost
, snap_id
, address
, optimizer
select hl.hash_value
, hl.text_subset
, hl.plan_hash_value
, hl.cost
, max(hl.snap_id)
, max(hl.address)
, max(hl.optimizer)
from (select /*+ ordered use_nl(sq) index(sq) */
ss.hash_value
, ss.text_subset
, sq.plan_hash_value
, nvl(sq.optimizer_cost,-9) cost
, ss.snap_id snap_id
, ss.address
, sq.optimizer_mode optimizer
from stats$sql_summary ss
, v$sql sq
where ss.snap_id = l_snap_id
and ss.dbid = p_dbid
and ss.instance_number = p_instance_number
and sq.hash_value = ss.hash_value
and sq.address = ss.address
and sq.plan_hash_value > 0
) hl
where not exists (select /*+ no_unnest */
from stats$sql_plan_usage spu
where spu.hash_value = hl.hash_value
and spu.text_subset = hl.text_subset
and spu.plan_hash_value
= hl.plan_hash_value
and spu.cost = hl.cost
group by hl.hash_value
, hl.text_subset
, hl.plan_hash_value
, hl.cost
, hl.optimizer;
/* For all new hash_value, plan_hash_value, cost combinations
just captured, get the optimizer plans, if we don't already
have them. Note that the plan (and hence the plan hash value)
comprises the access path and the join order (and not
variable factors such as the cardinality).
insert into stats$sql_plan
( plan_hash_value
, id
, operation
, options
, object_node
, object#
, object_owner
, object_name
, optimizer
, parent_id
, depth
, position
, cost
, cardinality
, bytes
, other_tag
, partition_start
, partition_stop
, partition_id
, other
, distribution
, cpu_cost
, io_cost
, temp_space
, snap_id
select /*+ ordered use_nl(s) use_nl(sp.p) */
new_plan.plan_hash_value
, sp.id
, max(sp.operation)
, max(sp.options)
, max(sp.object_node)
, max(sp.object#)
, max(sp.object_owner)
, max(sp.object_name)
, max(sp.optimizer)
, max(sp.parent_id)
, max(sp.depth)
, max(sp.position)
, max(sp.cost)
, max(sp.cardinality)
, max(sp.bytes)
, max(sp.other_tag)
, max(sp.partition_start)
, max(sp.partition_stop)
, max(sp.partition_id)
, max(sp.other)
, max(sp.distribution)
, max(sp.cpu_cost)
, max(sp.io_cost)
, max(sp.temp_space)
, max(new_plan.snap_id)
from (select /*+ index(spu) */
distinct
spu.plan_hash_value
, spu.hash_value
, spu.address
, spu.text_subset
, spu.snap_id
from stats$sql_plan_usage spu
where spu.snap_id = l_snap_id
and not exists (select /*+ nl_aj */ *
from stats$sql_plan ssp
where ssp.plan_hash_value
= spu.plan_hash_value
) new_plan
, v$sql s
, v$sql_plan sp
where sp.hash_value = new_plan.hash_value
and sp.address = new_plan.address
and s.hash_value = new_plan.hash_value
and s.address = new_plan.address
and s.hash_value = sp.hash_value
and s.address = sp.address
and s.child_number = sp.child_number
group by
new_plan.plan_hash_value
, sp.id;
END IF; /* snap level >=6 */
END snap_sql;
begin /* Function SNAP */
/* Get instance parameter defaults from stats$statspack_parameter,
or use supplied parameters.
If all parameters are specified, use them, otherwise get values
from the parameters not specified from stats$statspack_parameter.
statspack.qam_statspack_parameter
( p_dbid
, p_instance_number
, i_snap_level, i_session_id, i_ucomment, i_num_sql
, i_executions_th, i_parse_calls_th
, i_disk_reads_th, i_buffer_gets_th, i_sharable_mem_th
, i_version_count_th, i_all_init
, i_pin_statspack
, i_modify_parameter
, l_snap_level, l_session_id, l_ucomment, l_num_sql
, l_executions_th, l_parse_calls_th
, l_disk_reads_th, l_buffer_gets_th, l_sharable_mem_th
, l_version_count_th, l_all_init
, l_pin_statspack);
/* Generate a snapshot id */
select stats$snapshot_id.nextval
into l_snap_id
from dual
where rownum = 1;
/* Determine the serial# of the session to maintain stats for,
if this was requested.
if l_session_id > 0 then
if not GETSERIAL%ISOPEN then open GETSERIAL; end if;
fetch GETSERIAL into l_serial#;
if GETSERIAL%NOTFOUND then
/* Session has already disappeared - don't gather
statistics for this session in this snapshot */
l_session_id := 0;
l_serial# := 0;
end if; close GETSERIAL;
else
l_serial# := 0;
end if;
/* The instance has been restarted since the last snapshot */
if p_new_sga = 0
then
begin
p_new_sga := 1;
/* Get the instance startup time, and other characteristics */
insert into stats$database_instance
( dbid
, instance_number
, startup_time
, snap_id
, parallel
, version
, db_name
, instance_name
, host_name
select p_dbid
, p_instance_number
, p_startup_time
, l_snap_id
, p_parallel
, p_version
, p_name
, p_instance_name
, p_host_name
from sys.dual;
commit;
end;
end if; /* new SGA */
/* Work out the max undo stat time, used for gathering undo stat data */
select nvl(max(begin_time), to_date('01011900','DDMMYYYY'))
into l_max_begin_time
from stats$undostat
where dbid = p_dbid
and instance_number = p_instance_number;
/* Save the snapshot characteristics */
insert into stats$snapshot
( snap_id, dbid, instance_number
, snap_time, startup_time
, session_id, snap_level, ucomment
, executions_th, parse_calls_th, disk_reads_th
, buffer_gets_th, sharable_mem_th
, version_count_th, serial#, all_init)
values
( l_snap_id, p_dbid, p_instance_number
, SYSDATE, p_startup_time
, l_session_id, l_snap_level, l_ucomment
, l_executions_th, l_parse_calls_th, l_disk_reads_th
, l_buffer_gets_th, l_sharable_mem_th
, l_version_count_th, l_serial#, l_all_init);
/* Begin gathering statistics */
insert into stats$filestatxs
( snap_id
, dbid
, instance_number
, tsname
, filename
, phyrds
, phywrts
, singleblkrds
, readtim
, writetim
, singleblkrdtim
, phyblkrd
, phyblkwrt
, wait_count
, time
select l_snap_id
, p_dbid
, p_instance_number
, tsname
, filename
, phyrds
, phywrts
, singleblkrds
, readtim
, writetim
, singleblkrdtim
, phyblkrd
, phyblkwrt
, wait_count
, time
from stats$v$filestatxs;
insert into stats$tempstatxs
( snap_id
, dbid
, instance_number
, tsname
, filename
, phyrds
, phywrts
, singleblkrds
, readtim
, writetim
, singleblkrdtim
, phyblkrd
, phyblkwrt
, wait_count
, time
select l_snap_id
, p_dbid
, p_instance_number
, tsname
, filename
, phyrds
, phywrts
, singleblkrds
, readtim
, writetim
, singleblkrdtim
, phyblkrd
, phyblkwrt
, wait_count
, time
from stats$v$tempstatxs;
insert into stats$librarycache
( snap_id
, dbid
, instance_number
, namespace
, gets
, gethits
, pins
, pinhits
, reloads
, invalidations
, dlm_lock_requests
, dlm_pin_requests
, dlm_pin_releases
, dlm_invalidation_requests
, dlm_invalidations
select l_snap_id
, p_dbid
, p_instance_number
, namespace
, gets
, gethits
, pins
, pinhits
, reloads
, invalidations
, dlm_lock_requests
, dlm_pin_requests
, dlm_pin_releases
, dlm_invalidation_requests
, dlm_invalidations
from v$librarycache;
insert into stats$buffer_pool_statistics
( snap_id
, dbid
, instance_number
, id
, name
, block_size
, set_msize
, cnum_repl
, cnum_write
, cnum_set
, buf_got
, sum_write
, sum_scan
, free_buffer_wait
, write_complete_wait
, buffer_busy_wait
, free_buffer_inspected
, dirty_buffers_inspected
, db_block_change
, db_block_gets
, consistent_gets
, physical_reads
, physical_writes
select l_snap_id
, p_dbid
, p_instance_number
, id
, name
, block_size
, set_msize
, cnum_repl
, cnum_write
, cnum_set
, buf_got
, sum_write
, sum_scan
, free_buffer_wait
, write_complete_wait
, buffer_busy_wait
, free_buffer_inspected
, dirty_buffers_inspected
, db_block_change
, db_block_gets
, consistent_gets
, physical_reads
, physical_writes
from v$buffer_pool_statistics;
insert into stats$rollstat
( snap_id
, dbid
, instance_number
, usn
, extents
, rssize
, writes
, xacts
, gets
, waits
, optsize
, hwmsize
, shrinks
, wraps
, extends
, aveshrink
, aveactive
select l_snap_id
, p_dbid
, p_instance_number
, usn
, extents
, rssize
, writes
, xacts
, gets
, waits
, optsize
, hwmsize
, shrinks
, wraps
, extends
, aveshrink
, aveactive
from v$rollstat;
insert into stats$rowcache_summary
( snap_id
, dbid
, instance_number
, parameter
, total_usage
, usage
, gets
, getmisses
, scans
, scanmisses
, scancompletes
, modifications
, flushes
, dlm_requests
, dlm_conflicts
, dlm_releases
select l_snap_id
, p_dbid
, p_instance_number
, parameter
, sum("COUNT")
, sum(usage)
, sum(gets)
, sum(getmisses)
, sum(scans)
, sum(scanmisses)
, sum(scancompletes)
, sum(modifications)
, sum(flushes)
, sum(dlm_requests)
, sum(dlm_conflicts)
, sum(dlm_releases)
from v$rowcache
group by l_snap_id, p_dbid, p_instance_number, parameter;
/* Collect parameters every snapshot, to cater for dynamic
parameters changable while instance is running
if l_all_init = 'FALSE' then
insert into stats$parameter
( snap_id
, dbid
, instance_number
, name
, value
, isdefault
, ismodified
select l_snap_id
, p_dbid
, p_instance_number
, name
, value
, isdefault
, ismodified
from v$system_parameter;
else
insert into stats$parameter
( snap_id
, dbid
, instance_number
, name
, value
, isdefault
, ismodified
select l_snap_id
, p_dbid
, p_instance_number
, i.ksppinm
, sv.ksppstvl
, sv.ksppstdf
, decode(bitand(sv.ksppstvf,7),1,'MODIFIED',4,'SYSTEM_MOD','FALSE')
from stats$x$ksppi i
, stats$x$ksppsv sv
where i.indx = sv.indx;
end if;
/* To cater for variable size SGA - insert on each snapshot */
insert into stats$sga
( snap_id
, dbid
, instance_number
, name
, value
select l_snap_id
, p_dbid
, p_instance_number
, name
, value
from v$sga;
/* Get current allocation of memory in the SGA */
insert into stats$sgastat
( snap_id
, dbid
, instance_number
, pool
, name
, bytes
select l_snap_id
, p_dbid
, p_instance_number
, pool
, name
, bytes
from v$sgastat;
insert into stats$system_event
( snap_id
, dbid
, instance_number
, event
, total_waits
, total_timeouts
, time_waited_micro
select l_snap_id
, p_dbid
, p_instance_number
, event
, total_waits
, total_timeouts
, time_waited_micro
from v$system_event;
insert into stats$bg_event_summary
( snap_id
, dbid
, instance_number
, event
, total_waits
, total_timeouts
, time_waited_micro
select l_snap_id
, p_dbid
, p_instance_number
, e.event
, sum(e.total_waits)
, sum(e.total_timeouts)
, sum(e.time_waited_micro)
from v$session_event e
where e.sid in (select s.sid from v$session s where s.type = 'BACKGROUND')
group by l_snap_id, p_dbid, p_instance_number, e.event;
insert into stats$sysstat
( snap_id
, dbid
, instance_number
, statistic#
, name
, value
select l_snap_id
, p_dbid
, p_instance_number
, statistic#
, name
, value
from v$sysstat;
insert into stats$waitstat
( snap_id
, dbid
, instance_number
, class
, wait_count
, time
select l_snap_id
, p_dbid
, p_instance_number
, class
, "COUNT"
, time
from v$waitstat;
insert into stats$enqueue_stat
( snap_id
, dbid
, instance_number
, eq_type
, total_req#
, total_wait#
, succ_req#
, failed_req#
, cum_wait_time
select l_snap_id
, p_dbid
, p_instance_number
, eq_type
, total_req#
, total_wait#
, succ_req#
, failed_req#
, cum_wait_time
from v$enqueue_stat
where total_req# != 0;
insert into stats$latch
( snap_id
, dbid
, instance_number
, name
, latch#
, level#
, gets
, misses
, sleeps
, immediate_gets
, immediate_misses
, spin_gets
, sleep1
, sleep2
, sleep3
, sleep4
, wait_time
select l_snap_id
, p_dbid
, p_instance_number
, name
, latch#
, level#
, gets
, misses
, sleeps
, immediate_gets
, immediate_misses
, spin_gets
, sleep1
, sleep2
, sleep3
, sleep4
, wait_time
from v$latch;
insert into stats$latch_misses_summary
( snap_id
, dbid
, instance_number
, parent_name
, where_in_code
, nwfail_count
, sleep_count
, wtr_slp_count
select l_snap_id
, p_dbid
, p_instance_number
, parent_name
, "WHERE"
, sum(nwfail_count)
, sum(sleep_count)
, sum(wtr_slp_count)
from v$latch_misses
where sleep_count > 0
group by l_snap_id, p_dbid, p_instance_number
, parent_name, "WHERE";
insert into stats$resource_limit
( snap_id
, dbid
, instance_number
, resource_name
, current_utilization
, max_utilization
, initial_allocation
, limit_value
select l_snap_id
, p_dbid
, p_instance_number
, resource_name
, current_utilization
, max_utilization
, initial_allocation
, limit_value
from v$resource_limit
where limit_value != ' UNLIMITED'
and max_utilization > 0;
insert into stats$undostat
( begin_time
, end_time
, dbid
, instance_number
, snap_id
, undotsn
, undoblks
, txncount
, maxquerylen
, maxconcurrency
, unxpstealcnt
, unxpblkrelcnt
, unxpblkreucnt
, expstealcnt
, expblkrelcnt
, expblkreucnt
, ssolderrcnt
, nospaceerrcnt
select begin_time
, end_time
, p_dbid
, p_instance_number
, l_snap_id
, undotsn
, undoblks
, txncount
, maxquerylen
, maxconcurrency
, unxpstealcnt
, unxpblkrelcnt
, unxpblkreucnt
, expstealcnt
, expblkrelcnt
, expblkreucnt
, ssolderrcnt
, nospaceerrcnt
from v$undostat
where begin_time > l_max_begin_time
and begin_time + (1/(24*6)) <= end_time;
insert into stats$db_cache_advice
( snap_id
, dbid
, instance_number
, id
, name
, block_size
, buffers_for_estimate
, advice_status
, size_for_estimate
, estd_physical_read_factor
, estd_physical_reads
select l_snap_id
, p_dbid
, p_instance_number
, id
, name
, block_size
, buffers_for_estimate
, advice_status
, size_for_estimate
, estd_physical_read_factor
, estd_physical_reads
from v$db_cache_advice
where advice_status = 'ON';
insert into stats$pgastat
( snap_id
, dbid
, instance_number
, name
, value
select l_snap_id
, p_dbid
, p_instance_number
, name
, value
from v$pgastat;
insert into stats$instance_recovery
( snap_id
, dbid
, instance_number
, recovery_estimated_ios
, actual_redo_blks
, target_redo_blks
, log_file_size_redo_blks
, log_chkpt_timeout_redo_blks
, log_chkpt_interval_redo_blks
, fast_start_io_target_redo_blks
, target_mttr
, estimated_mttr
, ckpt_block_writes
select l_snap_id
, p_dbid
, p_instance_number
, recovery_estimated_ios
, actual_redo_blks
, target_redo_blks
, log_file_size_redo_blks
, log_chkpt_timeout_redo_blks
, log_chkpt_interval_redo_blks
, fast_start_io_target_redo_blks
, target_mttr
, estimated_mttr
, ckpt_block_writes
from v$instance_recovery;
if p_parallel = 'YES' then
insert into stats$dlm_misc
( snap_id
, dbid
, instance_number
, statistic#
, name
, value
select l_snap_id
, p_dbid
, p_instance_number
, statistic#
, name
, value
from v$dlm_misc;
end if; /* parallel */
/* Begin gathering Extended Statistics */
IF l_snap_level >= 5 THEN
snap_sql;
END IF; /* snap level >=5 */
IF l_snap_level >= 10 THEN
insert into stats$latch_children
( snap_id
, dbid
, instance_number
, latch#
, child#
, gets
, misses
, sleeps
, immediate_gets
, immediate_misses
, spin_gets
, sleep1
, sleep2
, sleep3
, sleep4
, wait_time
select l_snap_id
, p_dbid
, p_instance_number
, latch#
, child#
, gets
, misses
, sleeps
, immediate_gets
, immediate_misses
, spin_gets
, sleep1
, sleep2
, sleep3
, sleep4
, wait_time
from v$latch_children;
insert into stats$latch_parent
( snap_id
, dbid
, instance_number
, latch#
, level#
, gets
, misses
, sleeps
, immediate_gets
, immediate_misses
, spin_gets
, sleep1
, sleep2
, sleep3
, sleep4
, wait_time
select l_snap_id
, p_dbid
, p_instance_number
, latch#
, level#
, gets
, misses
, sleeps
, immediate_gets
, immediate_misses
, spin_gets
, sleep1
, sleep2
, sleep3
, sleep4
, wait_time
from v$latch_parent;
END IF; /* snap level >=10 */
/* Record level session-granular statistics if a specific session
has been requested
if l_session_id > 0
then
insert into stats$sesstat
( snap_id
, dbid
, instance_number
, statistic#
, value
select l_snap_id
, p_dbid
, p_instance_number
, statistic#
, value
from v$sesstat
where sid = l_session_id;
insert into stats$session_event
( snap_id
, dbid
, instance_number
, event
, total_waits
, total_timeouts
, time_waited_micro
, max_wait
select l_snap_id
, p_dbid
, p_instance_number
, event
, total_waits
, total_timeouts
, time_waited_micro
, max_wait
from v$session_event
where sid = l_session_id;
end if;
commit work;
RETURN l_snap_id;
end SNAP; /* Function SNAP */
begin /* STATSPACK body */
/* Query the database id, instance_number, database name, instance
name and startup time for the instance we are working on
/* Get information about the current instance */
open get_instance;
fetch get_instance into
p_instance_number, p_instance_name
, p_startup_time, p_parallel, p_version
, p_host_name;
close get_instance;
/* Select the database info for the db connected to */
open get_db;
fetch get_db into p_dbid, p_name;
close get_db;
/* Keep the package
sys.dbms_shared_pool.keep('PERFSTAT.STATSPACK', 'P');
/* Determine if the instance has been restarted since the previous snapshot
begin
select 1
into p_new_sga
from stats$database_instance
where startup_time = p_startup_time
and dbid = p_dbid
and instance_number = p_instance_number;
exception
when NO_DATA_FOUND then
p_new_sga := 0;
end;
end STATSPACK;
Warning: Package Body created with compilation errors.
SQL> show error
Errors for PACKAGE BODY STATSPACK:
LINE/COL ERROR
2045/3 PLS-00201: identifier 'SYS.DBMS_SHARED_POOL' must be declared
2045/3 PL/SQL: Statement ignoredWhen i compiled the package, it compiled with following error.
Warning: Package Body created with compilation errors.
SQL> show error
Errors for PACKAGE BODY STATSPACK:
LINE/COL ERROR
2045/3 PLS-00201: identifier 'SYS.DBMS_SHARED_POOL' must be declared
2045/3 PL/SQL: Statement ignored
SQL> -
Unique Constraint error while executing statspack.snap procedure
The following is the error which popped up when i was trying to execute statspack.snap procedure from perfstat user:
ORA-00001: unique constraint (PERFSTAT.STATS$LATCH_CHILDREN_PK) violated
ORA-06512: at "PERFSTAT.STATSPACK", line 1619
ORA-06512: at "PERFSTAT.STATSPACK", line 71
ORA-06512: at line 1
How could i resolve such a problem, as all the constraints and objects for this user are created while running the oracle supplied script 'spcreate.sql'.
If any 1 knows how to handle such a situation , can come forward n please help me out.SQL> execute statspack.snap (i_snap_level=>10);
ERROR at line 1:
ORA-00001: unique constraint (PERFSTAT.STATS$LATCH_CHILDREN_PK) violated
ORA-06512: at "PERFSTAT.STATSPACK", line 1619
ORA-06512: at "PERFSTAT.STATSPACK", line 71
ORA-06512: at line 1
Cause
-- Its because of the bug # 2384758.
"STATSPACK.SNAP GIVES ORA-1 ON STATS$LATCH_CHILDREN_PK WHEN I_SNAP_LEVEL=>10"
-- The STATS$LATCH_CHILDREN table has a primary key constraint on (snap_id, dbid, instance_number, latch#, child#).
Fix
-- This is fixed in 9.0.2 and will not be backported to earlier versions because the level 10 is not a normal level to be setting unless requested by oracle support. -
Please, do not read this thread. This is a test.
1. X$KGLLK, X$KGLPN --> definition
2. EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS(); job log--> where??
① You might see this Problem: Perf: Emd_maintenance.Execute_em_dbms_job_procs() Job Using All Cpu Doc ID: Note:308291.1.
② Oracle Metalink Doc ID 4636497 EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS() JOB DOES NOT STOP.
Extracts of the Document,
DBConsole is stopped the EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS() continues running each minute. This job must be stopped too because Agent is not collecting information because is down.
③ You can remove this as indicated in the Metalink Document that I have referenced in my first post. After that you can create this job manually by viewing How to create job EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS manually
Doc ID Note: 44033.1. You can then see if the problem persists.
Additionally you should perform these tasks at test sites and please read the documents carefully.
3. DBSNMP/SYSMAN user
4. dbconsole, emagent --> difference
5. sysaux tablespace segment --> organize
6. kill J001 on a test db and see what will happen
7. emagent.trc のログ
8. lock 関連テーブル整理
- dba_ddl_locks or dba_lock_internal
- v$lock and v$locked_object only shows enqueue locks, not library cache locks.
9. 10g default procedureのtruncate command
- enterprise manager のdefault procedureが、truncateを実行している。--> どれ？？
10. how about enabling trace event 10046 to see where your kernals are waiting?
--> 10046 trace event for node2 444 session
11. library cache invalidated object monitoring, reload monitoring
12. v$latch (and v$latch_children)
- v$libraryache latch get/pin
13. AWR report
- library cache 関連
- parsing 関連
- what is cpu time in Top 5 Timed Events
--> I'd take a guess that you have a problem with excessive CPU usage causing a library cache problem as a side effect.
-There are many notes in metalink, which will help you to identify root cause of "libary cache lock".
14. parameter
cursor_space_for_time=true,
●● その他
If the problem still, persists, I suggest you to run hunganlyze ' DIAGNOSING DATABASE HANGING ISSUES' see metalink.1. X$KGLLK, X$KGLPN --> definition
2. EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS(); job log--> where??
① You might see this Problem: Perf: Emd_maintenance.Execute_em_dbms_job_procs() Job Using All Cpu Doc ID: Note:308291.1.
② Oracle Metalink Doc ID 4636497 EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS() JOB DOES NOT STOP.
Extracts of the Document,
DBConsole is stopped the EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS() continues running each minute. This job must be stopped too because Agent is not collecting information because is down.
③ You can remove this as indicated in the Metalink Document that I have referenced in my first post. After that you can create this job manually by viewing How to create job EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS manually
Doc ID Note: 44033.1. You can then see if the problem persists.
Additionally you should perform these tasks at test sites and please read the documents carefully.
3. DBSNMP/SYSMAN user
4. dbconsole, emagent --> difference
5. sysaux tablespace segment --> organize
6. kill J001 on a test db and see what will happen
7. emagent.trc のログ
8. lock 関連テーブル整理
- dba_ddl_locks or dba_lock_internal
- v$lock and v$locked_object only shows enqueue locks, not library cache locks.
9. 10g default procedureのtruncate command
- enterprise manager のdefault procedureが、truncateを実行している。--> どれ？？
10. how about enabling trace event 10046 to see where your kernals are waiting?
--> 10046 trace event for node2 444 session
11. library cache invalidated object monitoring, reload monitoring
12. v$latch (and v$latch_children)
- v$libraryache latch get/pin
13. AWR report
- library cache 関連
- parsing 関連
- what is cpu time in Top 5 Timed Events
--> I'd take a guess that you have a problem with excessive CPU usage causing a library cache problem as a side effect.
-There are many notes in metalink, which will help you to identify root cause of "libary cache lock".
14. parameter
cursor_space_for_time=true,
●● その他
If the problem still, persists, I suggest you to run hunganlyze ' DIAGNOSING DATABASE HANGING ISSUES' see metalink. -
Hello everyone,
Note: Apologize for the bad formatting, tried but it seems I forgot how to use it
BANNER
Oracle Database 11g Release 11.2.0.2.0 - 64bit Production
I've seen high "*latch: row cache objects*" in SP/ASH report for ~14 hours back, when the users were unable to connect to the database. There were,
WARNING: inbound connection timed out (ORA-3136)
Time: 30-APR-2012 02:24:36
Tracing not turned on.
Tns error struct:
errors all over the alert log for the duration of 6 minutes of the problem.
I've put few records in bold due to which I concluded that the problem was with "dc_users" thing.
Can anybody tell me how/where I should proceed forward ?
SP report:Instance Efficiency Indicators
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %: 100.00 Redo NoWait %: 100.00
Buffer Hit %: 99.84 Optimal W/A Exec %: 100.00
Library Hit %: 97.43 Soft Parse %: 87.86
Execute to Parse %: 22.54 Latch Hit %: 99.95
Parse CPU to Parse Elapsd %: 0.30 % Non-Parse CPU: 87.83
Shared Pool Statistics Begin End
Memory Usage %: 45.09 46.98
% SQL with executions>1: 11.49 13.15
% Memory for SQL w/exec>1: 72.96 21.33
Top 5 Timed Events Avg %Total
~~~~~~~~~~~~~~~~~~ wait Call
Event Waits Time (s) (ms) Time
latch: row cache objects 6,655 634,260 95306 97.0
log file sync 289,923 6,469 22 1.0
CPU time 5,039 .8
db file sequential read 310,084 2,840 9 .4
log file parallel write 451,706 1,144 3 .2
ASH Report
Analysis Begin Time: 30-Apr-12 02:24:00
Analysis End Time: 30-Apr-12 02:30:00
Elapsed Time: 6.0 (mins)
Begin Data Source: DBA_HIST_ACTIVE_SESS_HISTORY
in AWR snapshot 12185
End Data Source: DBA_HIST_ACTIVE_SESS_HISTORY
in AWR snapshot 12185
Sample Count: 1,385
Average Active Sessions: 38.47
Avg. Active Session per CPU: 1.60
Report Target: None specified
Top User Events DB/Inst: NIKU/niku (Apr 30 02:24 to 02:30)
Avg Active
Event Event Class % Event Sessions
latch: row cache objects Concurrency 75.45 29.03
CPU + Wait for CPU CPU 9.75 3.75
log file sync Commit 3.83 1.47
db file sequential read User I/O 3.61 1.39
Top Event P1/P2/P3 Values DB/Inst: NIKU/niku (Apr 30 02:24 to 02:30)
Event % Event P1 Value, P2 Value, P3 Value % Activity
Parameter 1 Parameter 2 Parameter 3
latch: row cache objects 75.60 "42287858200","279","0" 75.60
address number tries
1* select addr, latch#, child#, name, misses, gets from v$latch_children where name like '%row%cache%objec%' order by gets , misses
niku> /
ADDR LATCH# CHILD# NAME MISSES GETS
0000000A16FF21C8 279 26 row cache objects 0 0
0000000A16FF14C8 279 2 row cache objects 0 0
00000009D88D7ED8 279 3 row cache objects 0 0
0000000A16FF1B48 279 14 row cache objects 0 0
00000009D88D8558 279 15 row cache objects 0 0
0000000A16FF1CE8 279 17 row cache objects 0 0
0000000A26265A28 279 19 row cache objects 0 0
0000000A16FF1E88 279 20 row cache objects 0 0
00000009D88D8898 279 21 row cache objects 0 0
0000000A26265BC8 279 22 row cache objects 0 0
0000000A16FF2028 279 23 row cache objects 0 0
00000009D88D8A38 279 24 row cache objects 0 0
0000000A26265D68 279 25 row cache objects 0 0
00000009D88D8BD8 279 27 row cache objects 0 0
0000000A26265F08 279 28 row cache objects 0 0
00000009D88D8D78 279 30 row cache objects 0 0
0000000A262660A8 279 31 row cache objects 0 0
0000000A16FF2508 279 32 row cache objects 0 0
0000000A16FF26A8 279 35 row cache objects 0 0
00000009D88D90B8 279 36 row cache objects 0 0
0000000A262663E8 279 37 row cache objects 0 0
0000000A262668C8 279 46 row cache objects 0 0
0000000A26266A68 279 49 row cache objects 0 0
0000000A16FF2368 279 29 row cache objects 0 11
0000000A16FF2848 279 38 row cache objects 0 116
0000000A16FF29E8 279 41 row cache objects 0 200
00000009D88D93F8 279 42 row cache objects 0 318
00000009D88D9258 279 39 row cache objects 0 1010
0000000A16FF2EC8 279 50 row cache objects 0 1406
00000009D88D9598 279 45 row cache objects 0 1472
0000000A26266588 279 40 row cache objects 0 1705
0000000A26266728 279 43 row cache objects 0 7383
0000000A16FF2B88 279 44 row cache objects 0 32346
00000009D88D98D8 279 51 row cache objects 19 63948
0000000A26265888 279 16 row cache objects 0 88045
0000000A26266248 279 34 row cache objects 0 141176
00000009D88D9738 279 48 row cache objects 0 326672
0000000A16FF19A8 279 11 row cache objects 867 1770385
00000009D88D8078 279 6 row cache objects 9 1979542
0000000A16FF2D28 279 47 row cache objects 2 3435018
00000009D88D86F8 279 18 row cache objects 2557 14956121
0000000A26265068 279 1 row cache objects 224 24335868
0000000A262653A8 279 7 row cache objects 29760 133991553
00000009D88D8F18 279 33 row cache objects 60612 677263122
00000009D88D83B8 279 12 row cache objects 23981 739014460
0000000A26265208 279 4 row cache objects 19973399 852043775
0000000A26265548 279 10 row cache objects 280137 856097342
00000009D88D8218 279 9 row cache objects 715879777 1219000976
0000000A262656E8 279 13 row cache objects 3856073 2397402780
0000000A16FF1668 279 5 row cache objects 12763217 2920278217
*0000000A16FF1808 279 8 row cache objects 67329804 4145389092*
51 rows selected.
niku> list
1 select addr, latch#, child#, name, misses, gets from v$latch_children where name like '%row%cache%objec%' order by gets , misses
niku> select distinct s.kqrstcln latch#,r.cache#,r.parameter name,r.type,r.subordinate#
from v$rowcache r,x$kqrst s
where r.cache#=s.kqrstcid
order by 1,4,5; 2 3 4
LATCH# CACHE# NAME TYPE SUBORDINATE#
1 3 dc_rollback_segments PARENT
2 1 dc_free_extents PARENT
3 4 dc_used_extents PARENT
4 2 dc_segments PARENT
5 0 dc_tablespaces PARENT
6 5 dc_tablespace_quotas PARENT
7 6 dc_files PARENT
*8 10 dc_users PARENT*
*8 7 dc_users SUBORDINATE 0*
*8 7 dc_users SUBORDINATE 1*
*8 7 dc_users SUBORDINATE 2*
9 8 dc_objects PARENT
9 8 dc_object_grants SUBORDINATE 0
10 17 dc_global_oids PARENT
11 12 dc_constraints PARENT
12 13 dc_sequences PARENT
13 16 dc_histogram_defs PARENT
13 16 dc_histogram_data SUBORDINATE 0
13 16 dc_histogram_data SUBORDINATE 1
14 54 dc_sql_prs_errors PARENT
15 32 kqlsubheap_object PARENT
16 19 dc_table_scns PARENT
16 19 dc_partition_scns SUBORDINATE 0
17 18 dc_outlines PARENT
18 14 dc_profiles PARENT
19 47 realm cache PARENT
19 47 realm auth SUBORDINATE 0
20 48 Command rule cache PARENT
21 49 Realm Object cache PARENT
21 49 Realm Subordinate Cache SUBORDINATE 0
22 46 Rule Set Cache PARENT
23 34 extensible security user and rol PARENT
24 35 extensible security principal pa PARENT
25 37 extensible security UID to princ PARENT
26 36 extensible security principal na PARENT
27 33 extensible security principal ne PARENT
28 38 XS security class privilege PARENT
29 39 extensible security midtier cach PARENT
30 43 AV row cache 1 PARENT
31 44 AV row cache 2 PARENT
32 45 AV row cache 3 PARENT
33 15 global database name PARENT
34 20 rule_info PARENT
35 21 rule_or_piece PARENT
35 21 rule_fast_operators SUBORDINATE 0
36 23 dc_qmc_ldap_cache_entries PARENT
37 52 qmc_app_cache_entries PARENT
38 53 qmc_app_cache_entries PARENT
39 27 qmtmrcin_cache_entries PARENT
40 28 qmtmrctn_cache_entries PARENT
41 29 qmtmrcip_cache_entries PARENT
42 30 qmtmrctp_cache_entries PARENT
43 31 qmtmrciq_cache_entries PARENT
44 26 qmtmrctq_cache_entries PARENT
45 9 qmrc_cache_entries PARENT
46 50 qmemod_cache_entries PARENT
47 24 outstanding_alerts PARENT
48 22 dc_awr_control PARENT
49 25 SMO rowcache PARENT
50 40 sch_lj_objs PARENT
51 41 sch_lj_oids PARENT
61 rows selected.
niku> select parameter, gets from v$rowcache order by gets desc;
PARAMETER GETS
dc_users 2802019571
dc_tablespaces 2405092307
dc_objects 1815427326jjk wrote:
I've already been thru the link that you've mentioned and unfortunately couldn't make much use of it.I didn't think it was really likely to be relevant, but there was always a long shot that it might have given you a clue.
Considering the "dc_users" had maximum gets, I thought (rather as per internet) that it might be the point of contention. However I did observe high misses on child# 9 which is "dc_objects". It's often the case that the misses is more important than the gets when you see lots of gets and misses on a few latches/caches - the bit that might have been most instructure was the dictionary cache bit from the AWR showing gets, misses, scans, scanmisses etc. It might have told us a little about what was going in and out of the dictionary cache and let us guess why.
In alert log:
Sun Apr 29 02:20:00 2012
29-APR-2012 02:20:00 -- xxxxxxx package - REGRANT_READONLY Begin re-grant read only roles
Sun Apr 29 02:24:34 2012
29-APR-2012 02:24:34 -- xxxxxxx package - REGRANT_READONLY End re-grant read only roles
Sun Apr 29 02:30:00 2012
29-APR-2012 02:30:00 -- xxxxxxx package - REGRANT_READWRITE Begin re-grant read write roles
Sun Apr 29 02:32:02 2012
29-APR-2012 02:32:02 -- xxxxxxx package - REGRANT_READWRITE End re-grant read write roles
Is this code that "regrants" roles to users who already have them ? That's what it sounds like, and that sounds like something that would impact on various parts of the dictionary cache, especially dc_users, and possibly dc_obejcts.
CPU per Elap per Old
Executions Rows Processed Rows per Exec Exec (s) Exec (s) Hash Value
161,198 1,244 0.0 0.00 0.00 978935325
select /*+ rule */ c.name, u.name from con$ c, cdef$ cd, user$ u
where c.con# = cd.con# and cd.enabled = :1 and c.owner# = u.us
er#
159,955 159,952 1.0 0.00 0.00 2458412332
select o.name, u.name from obj$ o, user$ u where o.obj# = :1 an
d o.owner# = u.user#
159,932 6 0.0 0.00 0.00 2636710067
insert into objauth$(option$,grantor#,obj#,privilege#,grantee#,c
ol#,sequence#) values(decode(:1,0,null,:1),:2,:3,:4,:5,decode(:6
,0,null,:6),object_grant.nextval)
147,168 147,168 1.0 0.00 0.00 3468666020
select text from view$ where rowid=:1
124,635 124,635 1.0 0.00 0.00 564166580
select count(*) from ( select u.
name from registry$ r, us
er$ u where r.status in (1,3,5)
and r.namespace = 'SERVER'The first one looks like a response to a constraint being breached.
The third one looks like something that might happen when you grant a privilege on an object to a user - and maybe the first one happens if the user has already got it and the insert raises a "duplicate key" error. The fourth one commonly happens when you have to re-optimize a query containing a view - and when you execute DDL (such as changing privileges on an object) you invalidate SQL and have to re-optimize it eventually. I can't remember where I've seen the second one appearing.
If you have a process that tries to do a lot of grants on objects to users and roles in a very short time, it's quite likely to create havoc in the dictionary cache - check what that package was up to and why it runs.
What is the missing information ?When I looked at some of your posting, the output didn't match the query, some of the later columns had gone missing - this might have been my browser rather than your input though.
Regards
Jonathan Lewis -
Release the space from Tools tablespace
Hi,
I have found that TOOLS tablespace is 99%.
The tools tablespace is typically used for collecting database statistics – not part of the application. These include Quest and Perfstat. How can I check at the objects in the tools tablespace to see what has grown and then determine if we need to purge data and reorg the objects.
The mount point for this database is only 8 gig and is 84% used so we should not add “overhead” space unless absolutely necessary. The tools tablespace is already large for the size of the rest of the database.
/dev/orabwelv 8388608 7011424 1377184 84% /ORACLE/BWEBPRD
These are the contents in the tablespace
OWNER TABLE_NAME OBJECT_TYPE TABLESPACE_NAME
ORACLE PLAN_TABLE TABLE TOOLS
ORACLE_APP STPL_DBAPRVS_PENDINGL TABLE TOOLS
ORACLE_APP STPL_DBAPRVS_ACTIVITY_LOGL TABLE TOOLS
ORACLE T_WEBBPRD TABLE TOOLS
POSTD PLAN_TABLE TABLE TOOLS
MONITORER TABLESPACE_GROWTH TABLE TOOLS
MONITORER SEGMENT_GROWTH TABLE TOOLS
OWNER TABLE_NAME OBJECT_TYPE TABLESPACE_NAME
PERFSTAT STATS$PGA_TARGET_ADVICE TABLE TOOLS
PERFSTAT STATS$SQL_WORKAREA_HISTOGRAM TABLE TOOLS
PERFSTAT STATS$SHARED_POOL_ADVICE TABLE TOOLS
PERFSTAT STATS$STATSPACK_PARAMETER TABLE TOOLS
PERFSTAT STATS$INSTANCE_RECOVERY TABLE TOOLS
PERFSTAT STATS$PARAMETER TABLE TOOLS
PERFSTAT STATS$IDLE_EVENT TABLE TOOLS
PERFSTAT STATS$PGASTAT TABLE TOOLS
PERFSTAT STATS$SEG_STAT_OBJ TABLE TOOLS
PERFSTAT STATS$SEG_STAT TABLE TOOLS
PERFSTAT STATS$SQL_PLAN TABLE TOOLS
OWNER TABLE_NAME OBJECT_TYPE TABLESPACE_NAME
PERFSTAT STATS$SQL_PLAN_USAGE TABLE TOOLS
PERFSTAT STATS$UNDOSTAT TABLE TOOLS
PERFSTAT STATS$DLM_MISC TABLE TOOLS
PERFSTAT STATS$RESOURCE_LIMIT TABLE TOOLS
PERFSTAT STATS$SQL_STATISTICS TABLE TOOLS
PERFSTAT STATS$SQLTEXT TABLE TOOLS
PERFSTAT STATS$SQL_SUMMARY TABLE TOOLS
PERFSTAT STATS$ENQUEUE_STAT TABLE TOOLS
PERFSTAT STATS$WAITSTAT TABLE TOOLS
PERFSTAT STATS$BG_EVENT_SUMMARY TABLE TOOLS
PERFSTAT STATS$SESSION_EVENT TABLE TOOLS
OWNER TABLE_NAME OBJECT_TYPE TABLESPACE_NAME
PERFSTAT STATS$SYSTEM_EVENT TABLE TOOLS
PERFSTAT STATS$SESSTAT TABLE TOOLS
PERFSTAT STATS$SYSSTAT TABLE TOOLS
PERFSTAT STATS$SGASTAT TABLE TOOLS
PERFSTAT STATS$SGA TABLE TOOLS
PERFSTAT STATS$ROWCACHE_SUMMARY TABLE TOOLS
PERFSTAT STATS$ROLLSTAT TABLE TOOLS
PERFSTAT STATS$BUFFER_POOL_STATISTICS TABLE TOOLS
PERFSTAT STATS$LIBRARYCACHE TABLE TOOLS
PERFSTAT STATS$LATCH_MISSES_SUMMARY TABLE TOOLS
PERFSTAT STATS$LATCH_PARENT TABLE TOOLS
OWNER TABLE_NAME OBJECT_TYPE TABLESPACE_NAME
PERFSTAT STATS$LATCH_CHILDREN TABLE TOOLS
PERFSTAT STATS$LATCH TABLE TOOLS
PERFSTAT STATS$TEMPSTATXS TABLE TOOLS
PERFSTAT STATS$FILESTATXS TABLE TOOLS
PERFSTAT STATS$DB_CACHE_ADVICE TABLE TOOLS
PERFSTAT STATS$SNAPSHOT TABLE TOOLS
PERFSTAT STATS$LEVEL_DESCRIPTION TABLE TOOLS
PERFSTAT STATS$DATABASE_INSTANCE TABLE TOOLS
Please Suggest
Message was edited by:
user592074Thanks Chandra!
Request you to kindly suggest me how to release the sapce from tool table. Database version is 9.2.0.6 (64 bi Please find the output below.
SEGMENT_NAME SIZE_MB
PLAN_TABLE .125
SEGMENT_GROWTH 25
STATS$BG_EVENT_SUMMARY 2
STATS$BG_EVENT_SUMMARY_PK 2
STATS$BUFFER_POOL_STATISTICS 1
STATS$BUFFER_POOL_STATS_PK 1
STATS$DATABASE_INSTANCE 1
STATS$DATABASE_INSTANCE_PK 1
STATS$DB_CACHE_ADVICE 2
STATS$DB_CACHE_ADVICE_PK 1
STATS$DLM_MISC 1
STATS$DLM_MISC_PK 1
STATS$ENQUEUE_STAT 2
STATS$ENQUEUE_STAT_PK 2
STATS$FILESTATXS 3
STATS$FILESTATXS_PK 3
STATS$IDLE_EVENT .125
STATS$IDLE_EVENT_PK .125
STATS$INSTANCE_RECOVERY 1
STATS$INSTANCE_RECOVERY_PK 1
STATS$LATCH 25
STATS$LATCH_CHILDREN 1
STATS$LATCH_CHILDREN_PK 1
STATS$LATCH_MISSES_SUMMARY 1
STATS$LATCH_MISSES_SUMMARY_PK 1
STATS$LATCH_PARENT 1
STATS$LATCH_PARENT_PK 1
STATS$LATCH_PK 22
STATS$LEVEL_DESCRIPTION .125
STATS$LEVEL_DESCRIPTION_PK .125
STATS$LIBRARYCACHE 1
STATS$LIBRARYCACHE_PK 1
STATS$PARAMETER 21
STATS$PARAMETER_PK 24
STATS$PGASTAT 1
STATS$PGA_TARGET_ADVICE 1
STATS$PGA_TARGET_ADVICE_PK 1
STATS$RESOURCE_LIMIT 1
STATS$RESOURCE_LIMIT_PK 1
STATS$ROLLSTAT 2
STATS$ROLLSTAT_PK 1
STATS$ROWCACHE_SUMMARY 3
STATS$ROWCACHE_SUMMARY_PK 3
STATS$SEG_STAT 3
STATS$SEG_STAT_OBJ 1
STATS$SEG_STAT_OBJ_PK 1
STATS$SEG_STAT_PK 1
STATS$SESSION_EVENT 1
STATS$SESSION_EVENT_PK 1
STATS$SESSTAT 1
STATS$SESSTAT_PK 1
STATS$SGA 1
STATS$SGASTAT 3
STATS$SGASTAT_U 5
STATS$SGA_PK 1
STATS$SHARED_POOL_ADVICE 1
STATS$SHARED_POOL_ADVICE_PK 1
STATS$SNAPSHOT 1
STATS$SNAPSHOT_PK 1
STATS$SQLTEXT 5
STATS$SQLTEXT_PK 1
STATS$SQL_PGASTAT_PK 1
STATS$SQL_PLAN 5
STATS$SQL_PLAN_PK 1
STATS$SQL_PLAN_USAGE 5
STATS$SQL_PLAN_USAGE_HV 1
STATS$SQL_PLAN_USAGE_PK 1
STATS$SQL_STATISTICS 1
STATS$SQL_STATISTICS_PK 1
STATS$SQL_SUMMARY 17
STATS$SQL_SUMMARY_PK 8
STATS$SQL_WORKAREA_HISTOGRAM 1
STATS$SQL_WORKAREA_HIST_PK 1
STATS$STATSPACK_PARAMETER .125
STATS$STATSPACK_PARAMETER_PK .125
STATS$SYSSTAT 21
STATS$SYSSTAT_PK 25
STATS$SYSTEM_EVENT 3
STATS$SYSTEM_EVENT_PK 4
STATS$TEMPSTATXS 1
STATS$TEMPSTATXS_PK 1
STATS$UNDOSTAT 1
STATS$UNDOSTAT_PK 1
STATS$WAITSTAT 1
STATS$WAITSTAT_PK 2
STPL_DBAPRVS_ACTIVITY_LOG .0625
STPL_DBAPRVS_PENDING .0625
STPL_DBAPRVS_PENDING_PK .0625
TABLESPACE_GROWTH .3125
T_WEBBPRD .0625
90 rows selected.
Message was edited by:
user592074 -
제품 : ORACLE SERVER
작성날짜 : 2004-10-13
BUFFER CACHE 내의 HOT BLOCK을 찾기
=============================
PURPOSE
ORACLE은 data block을 효율적으로 관리하기 위하여 buffer cache를
사용하고 있다.
이 buffer cache는 각각 buffer handle을 가지고 있으며 buffer cache
chain에 의하여 관리가 되고 있다. oracle은 원하는 block을 빨리 찾기
위하여 block의 주소를 hash key로 사용하는 hash function을 사용하여
특정 buffer chain을 찾고 이 list를 scan하여 원하는 block을 찾게
된다. 따라서 특정 block은 하나의 buffer chain에 의하여 관리된다.
이 buffer cache chains latch cocntention은 주로 이 buffer chain에
의하여 관리되는 buffer수가 많거나 hot block(hot buffer)에 의한 경우로
나누어 볼 수 있다.
아래에서는 hot block을 찾는 방법에 대하여 설명하고 있다.
Explanation
1. v$latch_children에서 contention이 많은 buffer cache chain
latch들을 찾는다.
select * from
(select l.child#, l.addr, l.sleeps, l.sleep1, l.sleep3
from
v$latch_children l
where l.latch#= 66
order by l.sleeps desc
where rownum < 11
이 쿼리를 일정한 간격을 두고 수행하여 현 시점에서 sleeps이 많은
latch를 선별한다.
CHILD# ADDR SLEEPS SLEEP1 SLEEP3
29406 33F84420 301809 242441 4041
2532 33BEDB68 233945 213363 651
3642 33C13A70 215950 181390 2330
3575 33C115CC 198600 102161 14556
25216 33EF50B8 195763 176779 796
33288 34008F18 180123 155168 1735
18475 33E0EA3C 169387 156205 405
32301 33FE7354 152855 137046 616
20770 33E5D150 91845 74889 889
2533 33BEDBF4 78774 74539 110
10 rows selected.
CHILD# ADDR SLEEPS SLEEP1 SLEEP3
29406 33F84420 301809 242441 4041 *
2532 33BEDB68 234272 213670 651
3642 33C13A70 216086 181520 2330
3575 33C115CC 198600 102161 14556 *
25216 33EF50B8 196068 177069 797
33288 34008F18 180123 155168 1735 *
18475 33E0EA3C 169598 156408 405
32301 33FE7354 152855 137046 616 *
20770 33E5D150 91845 74889 889 *
2533 33BEDBF4 78855 74618 110
10 rows selected.
현 시점에서 높은 sleeps 변화를 보이는 latch#은 2532, 3642,
25216, 18475, 2533 latch들이다.
2. 이제 이들 latch들로 관리되고 있는 buffer들 중에서 hot block들을
찾는다.
select b.hladdr, l.sleeps, l.sleep3, b.tch,
b.dbarfil, b.dbablk, b.state
from x$bh b, v$latch_children l
where l.child#
in
(2532, 3642, 25216, 18475, 2533)
and b.hladdr= l.addr
order by tch
x$bh의 tch는 touch count를 의미하므로 이 값이 가장 큰
것부터 hot block들이라고 볼 수 있다.
HLADDR SLEEPS SLEEP3 TCH DBARFIL DBABLK
STATE
33E0EA3C 169818 405 0 192
102764 1
33E0EA3C 169818 405 0 70
97847 1
33E0EA3C 169818 405 0 106
38012 1
33EF50B8 196361 797 1 193
115327 1
33C13A70 216224 2330 91 33
4494 1
33BEDBF4 78952 110 104 33
3385 1
33BEDB68 234617 651 132 33
3384 1
33EF50B8 196361 797 146 24
25614 1
33E0EA3C 169818 405 164 32
10107 1
3. 아래의 쿼리를 수행하여 hot block과 관련된 object를 찾는다.
select segment_name , segment_type , owner
from sys.dba_extents
where file_id = 32
and 10107 between block_id and (block_id+(blocks-1))
SEGMENT_NAME SEGMENT_TYPE OWNER
FRED_TABLE TABLE MARY
4. hot block이 확인된 object의 header block인지 확인해 본다.
select header_file, header_block, freelist_groups, freelists
from dba_segments where
segment_name = 'FRED_TABLE'
and owner = 'MARY'
HEADER_FILE HEADER_BLOCK FREELIST_GROUPS FREELISTS
32 4769 4 4
해당 block(10107)이 segment header block ~ segment header
block(4769) + free list group(4) 사이에 들어가지 않으므로
data block이다.
Example
none
Reference Documents
none -
Hi,
I am facing the following in my DB.Oracle version is 11.1.0.7.0
Event Waits Time(s) Avg wait (ms) % DB time Wait Class
latch: cache buffers chains 37,910,465 17,344 0 42.64 Concurrency
I checked the SQL causing the wait using following query.
select count(*), SQL_ID from gv$active_session_history where event like '%cache buffers%' group by SQL_ID;
COUNT(*) SQL_ID
1
3 3wunvbmu64d8j
2 9q2ux8f92za7m
36000 47g8dw48ghk5s
2 5arqxftxr7tjr
Also i tried the following.
select count(*) child_count, sum(gets) sum_gets, sum(misses) sum_misses, sum(sleeps) sum_sleeps from v$latch_children where name = 'cache buffers chains';
CHILD_COUNT SUM_GETS SUM_MISSES SUM_SLEEPS
65536 1.5723E+10 3163139088 56744600
SQL> select P1 from v$session_wait where event = 'cache buffer chains';
no rows selected
How do i proceed with this?
SQL ID - 47g8dw48ghk5s is an update query.Can increasing freelists of this table help ??Kindly assist me.
Thanks.user10698496 wrote:
Elapsed Time (s) CPU Time (s) Executions Elap per Exec (s) % Total DB Time SQL Id SQL Module SQL Text
29,725 6,747 82,289 0.36 73.08 47g8dw48ghk5s app2 (TNS V1-V3) UPDATE ZH_TBL SE
CPU Time (s) Elapsed Time (s) Executions CPU per Exec (s) % Total % Total DB Time SQL Id SQL Module SQL Text
6,747 29,725 82,289 0.08 62.52 73.08 47g8dw48ghk5s app2 (TNS V1-V3) UPDATE ZH_TBL SE...
Assuming that this is the standard one-hour snapshot that seems to be a rather small number of executions to waste so much latch time.
Moreover, since it's an update by rowid it's surprising that it should take so much CPU per executions unless you have a very large number of indexes on the table which have to be maintained.
Can you show us the "Load profile" and "Top 5 timed events" from the same period, plus the system summary bit (memory, cache size, CPU count) that's near the top of the report.
In your position I'd run up a little query to look at the stats in v$sql for that sql_id, and watch the executions, buffer_gets, cpu_time etc. changing over a few minutes in case there's something funny with the snapshot and youre losing large numbers in the execution counts. (I'd be particularly interested in the number of CPUs you have, and the CPU load on the system - sometimes you can get really wierd latching issue which are basically caused by CPU loading, especially on NUMA systems).
Since you've got the ASH data, there's also more information you can get from there - is it
a) the same latch all the time
b) a small number of different latches
c) a small number of different latches, but the same latch for any specific sid/serial
d) does the latch seem to change over time
If it's a small number of fixed latches you may be able to query the buffer cache with the latch address to see if there are any "obvious" blocks with a high touch count covered by those latches - they may be things like the root blocks of indexes used for referential integrity.
If the latch seems to keep moving it could be an indication that the update is slowly travelling along a table and every block is subject to competition from a number of concurrent processes.
Kyle Hailey has some sample queries against ASH that may point you in the right direction: http://sites.google.com/site/embtdbo/wait-event-documentation/oracle-latch-cache-buffers-chains
If you can spot a session hitting the problem you could also start tracing it to see if that level of detail gives you more clues, and I'd also start thinking about read up Tanel's notes.
Regards
Jonathan Lewis
To post code, statspack/AWR report, execution plans or trace files, START and END the text with the tag {noformat}{noformat} (the word "code" in lowercase, curly brackets, no spaces) so that the text appears in fixed format.
There is a +"Preview"+ tab at the top of the text entry panel. Use this to check what your message will look like before you post the message. If it looks a complete mess you're unlikely to get a response. (Click on the +"Plain text"+ tab if you want to edit the text to tidy it up.) -
Hello Team:
I ran a metalink script to report the shared pool utilization recently. I took this output when the database was on peak load.
SQL> /
Obj mem: 66435759 bytes (63.36MB)
Shared sql: 324219036 bytes (309.2MB)
Cursors: 341207073 bytes (325.4MB)
Free memory: 67228508 bytes (64.11MB)
Shared pool utilization (total): 468785754 bytes (447.07MB)
Shared pool allocation (actual): 754974720bytes (720MB)
Percentage Utilized: 91%
does this mean I have to add more space to shared pool. If so what is the threshold value?
Regards,
BalaBhawani nandan Prasad - Principal DBA -- See a to z diagnostics about Shared pool
1. Memory 2
a. Shared Pool 2
1. Introduction 2
2. Architecture 2
3. Scripts for different DBA tasks: 5
a.Measure object usage inside the shared pool and Tune shared pool 7
b.Check reload problem in library cache 12
c.Find the large queries in the shared pool library cache (using > 4mb each) 13
d.Find objects that can be considered pining into the shared pool 13
e.LRU work and objects were loaded and flushed 13
f.How much are waiting for Library Cache Latch 14
g.Queries identical but aren’t shared. 14
h.Get Biggest chunk of free memory. 14
i.Check the shared pool reserved size status 16
j.When having multiple subheaps: 16
k.Check shared pool at first glance quick diagnostics 17
l.Memory Usage - object list level view 17
m.Loads Number of times object has been loaded 17
n.Check number of times and object has been executed 18
o.Check shared pool in more details 18
p.Library Cache Statistics 18
q.Reserve Pool Settings 19
r.Pinned Objects 19
s.Finding literal SQL 19
t.Finding the Library Cache hit ratio 19
u. Row Cache Misses – Dictionary cache stats 19
v. Checking hash chain lengths 20
w. Checking for high version counts 20
x. Finding statement/s which use lots of shared pool memory 20
y. Allocations causing shared pool memory to be 'aged' out 21
z. Issues in various Oracle Releases 21
4. Terminology 22
5. Oracle 11g Caching and Pooling – SQL Result Cache 27
6. References 37
2. SQL 38
3. Statistics 38
4. Wait events 38
5. Schema 39
6. General 39
a. Scripts 39
1. accept.sql 39
1. Memory
a. Shared Pool
1. Introduction
Shared pool is used to cache different types of data such as textual and executable forms of PL/SQL blocks and SQL statements, dictionary cache data, and other data in SGA. Additional shared memory needed in the SHARED POOL if using ASM storage. Gathering schema/database stats (table/index stats) makes database query performance better and it reduce utilization of shared pool. Hence, practice to schedule job to gather stats regularly which suites your database performance. If you use shared pool effectively you can reduce resource consumption in at least four ways
1. Parse overhead is avoided if the SQL statement is already in the shared pool. This saves CPU resources on the host and elapsed time for the end user.
2. Latching resource usage is significantly reduced, which results in greater scalability.
3. Shared pool memory requirements are reduced, because all applications use the same pool of SQL statements and dictionary resources.
4. I/O resources are saved, because dictionary elements that are in the shared pool do not require disk access.
This sharable area of memory is managed as a sophisticated cache and heap manager rolled into one. It has 3 fundamental problems to overcome:
1. The unit of memory allocation is not a constant - memory allocations from the pool can be anything from a few bytes to many kilobytes
2. Not all memory can be 'freed' when a user finishes with it (as is the case in a traditional heap manager) as the aim of the shared pool is to maximize share of information. The information in the memory may be useful to another session - Oracle cannot know in advance if the items will be of any use to anyone else or not.
3. There is no disk area to page out to so this is not like a traditional cache where there is a file backing store. Only "rewriteable" information can be discarded from the cache and it has to be re-created when it is next needed.
Oracle 10g architecture of Shared pool:
Library Cache Shared SQL Area (Hash Value, SQL source, Execution plan)
Data Dictionary Cache
Enqueues Fixed Area Other
Latches
Oracle 11g architecture of Shared pool:
Library Cache Shared SQL Area (Hash Value, SQL source, Execution plan)
Data Dictionary Cache
Result Cache
Enqueues Fixed Area Other
Latches
1. Library Cache
Shared Sql Area: contains Parsed SQL and execution Plans for statements already run against the database. This area allows SQL execution plans to be reused by many users.
Private SQL Area: Private SQL areas are non-shared memory areas assigned to unique user sessions.
Pl/sql Area: contains the recently executed Procedures, Functions and Packages.
Control Structures: Common control structure information example Memory for Latches and locks, sequence cache.
2. Dictionary cache known as the row cache.
Dictionary cache stores all the metadata info of tables and views in the database, Names and data types of the columns in the database, Object and system privileges of all the Users. Oracle maintains the stats of all the objects in the shared pool, if any of the memory objects are not used from the last 3 seconds, these memory objects will be aged out and will be removed from the cache. All the Shared Pool Structures are maintained by a LRU (least recently Used) algorithm, by which Oracle removes the objects from the shared Pool, until there is enough free space in the shared Pool to keep new Object.
3. Scripts for different DBA tasks:
Dictionary Views for shared POOL:
NON-RAC
V$DB_CACHE_ADVICE
V$DB_OBJECT_CACHE
V$DLM_LATCH
V$DLM_LOCKS
V$LATCH
V$LATCHHOLDER
V$LATCHNAME
V$LATCH_CHILDREN
V$LATCH_MISSES
V$LATCH_PARENT
V$LIBRARYCACHE
V$LOCK
V$LOCKED_OBJECT
V$LOCKS_WITH_COLLISIONS
V$LOCK_ACTIVITY
V$LOCK_ELEMENT
V$OPEN_CURSOR
V$PROCESS
V$PX_PROCESS
V$PX_PROCESS_SYSSTAT
V$PX_SESSION
V$PX_SESSTAT
V$ROWCACHE
V$ROWCACHE_PARENT
V$ROWCACHE_SUBORDINATE
V$SESSION
V$SESSION_CONNECT_INFO
V$SESSION_CURSOR_CACHE
V$SESSION_EVENT
V$SESSION_LONGOPS
V$SESSION_OBJECT_CACHE
V$SESSION_WAIT
V$SESSTAT
V$SESS_IO
V$SGA
V$SGASTAT
V$SGAINFO
V$SGA_DYAMIC_COMPONENTS
V$SGA_DYNAMIC_FREE_MEMORY
V$SGA_RESIZE_OPS
V$SGA_CURRENT_RESIZE_OPS
v$shared_pool_advice
V_$SHARED_POOL_ADVICE
V$SHARED_POOL_RESERVED
V$SHARED_SERVER
V$SORT_SEGMENT
V$SORT_USAGE
V$SQL
V$SQLAREA
V$SQLTEXT
V$SQLTEXT_WITH_NEWLINES
V$SQL_BIND_DATA
V$SQL_BIND_METADATA
V$SQL_CURSOR
V$SQL_SHARED_CURSOR
V$SQL_SHARED_MEMORY
V$STATNAME
V$SUBCACHE
V$SYSSTAT
V$SYSTEM_CURSOR_CACHE
V$SYSTEM_EVENT
V$SYSTEM_PARAMETER
X$KSMSP
RAC
GV$LATCH
GV$LATCHHOLDER
GV$LATCHNAME
GV$LATCH_CHILDREN
GV$LATCH_MISSES
GV$LATCH_PARENT
GV$LIBRARYCACHE
GV$LOCK
GV$LOCKED_OBJECT
GV$LOCKS_WITH_COLLISIONS
GV$LOCK_ACTIVITY
GV$LOCK_ELEMENT
GV$PROCESS
GV$PX_PROCESS
GV$PX_PROCESS_SYSSTAT
GV$PX_SESSION
GV$PX_SESSTAT
GV$ROWCACHE
GV$ROWCACHE_PARENT
GV$ROWCACHE_SUBORDINATE
GV$SESSION
GV$SESSION_CONNECT_INFO
GV$SESSION_CURSOR_CACHE
GV$SESSION_EVENT
GV$SESSION_LONGOPS
GV$SESSION_OBJECT_CACHE
GV$SESSION_WAIT
GV$SESSTAT
GV$SESS_IO
GV$SGA
GV$SGASTAT
gv$shared_pool_advice
GV$SHARED_POOL_RESERVED
GV$SHARED_SERVER
GV$SORT_SEGMENT
GV$SORT_USAGE
GV$SQL
GV$SQLAREA
GV$SQLTEXT
GV$SQLTEXT_WITH_NEWLINES
GV$SQL_BIND_DATA
GV$SQL_BIND_METADATA
GV$SQL_CURSOR
GV$SQL_SHARED_CURSOR
GV$SQL_SHARED_MEMORY
GV$STATNAME
GV$SUBCACHE
GV$SYSSTAT
GV$SYSTEM_CURSOR_CACHE
GV$SYSTEM_EVENT
GV$SYSTEM_PARAMETER
GV$WAITSTAT
GV$_LOCK
a.Measure object usage inside the shared pool and Tune shared pool
set pagesize 132
column owner format a16
column name format a36
column sharable_mem format 999,999,999
column executions format 999,999,999
prompt
prompt Memory Usage of Shared Pool Order - Biggest First
prompt
column name format 45
select owner, name||' - '||type name, sharable_mem from v$db_object_cache
where sharable_mem > 10000
and type in ('PACKAGE', 'PACKAGE BODY', 'FUNCTION', 'PROCEDURE')
order by sharable_mem desc
prompt
prompt Loads into Shared Pool - Most Loads First
prompt
select owner, name||' - '||type name, loads , sharable_mem from v$db_object_cache
where loads > 3
and type in ('PACKAGE', 'PACKAGE BODY', 'FUNCTION', 'PROCEDURE')
order by loads desc
prompt
prompt Executions of Objects in the Shared Pool - Most Executions First
prompt
select owner, name||' - '||type name, executions from v$db_object_cache
where executions > 100
and type in ('PACKAGE', 'PACKAGE BODY', 'FUNCTION', 'PROCEDURE')
order by executions desc
select 'If the values for the EXEC and LOADS close increase SHARED_POOL_SIZE!' from dual ;
set feedback off
set linesize 80
set pagesize 52
clear columns
clear breaks
col executions HEADING EXEC
col sharable_mem heading SHAMEM
col owner format a8
col name format a30
col type format a12
set numwidth 8
ttitle center 'Data Base Objects Owned by All Users Statistics' skip 2
select name, type, sharable_mem, loads, executions, pins
from sys.v_$db_object_cache ;
b.Check reload problem in library cache
select namespace, pins, reloads from v$librarycache;
show parameters shared_pool
select bytes/1024/1024 from v$sgastat where pool='shared pool' and name='free memory';
c.Find the large queries in the shared pool library cache (using > 4mb each)
SELECT sql_text "Stmt", count(*), sum(sharable_mem) "Mem",
sum(users_opening) "Open", sum(executions) "Exec"
FROM v$sql GROUP BY sql_text HAVING sum(sharable_mem) > 4096000;
d.Find objects that can be considered pining into the shared pool
column name format a40
column owner format a15
select owner, name, executions, locks, pins, loads, kept from v$db_object_cache where loads > 10;
create temp table and insert records of candidates to be pinned.
CREATE TABLE LRU_TMP AS SELECT * FROM X$KSMLRU;
INSERT INTO LRU_TMP SELECT * FROM X$KSMLRU;
Use the LRU_TMP table for analysis.
SELECT USERNAME, KSMLRCOM, KSMLRHON, KSMLRNUM, KSMLRSIZ, SQL_TEXT
FROM V$SQLAREA A, LRU_TMP K, V$SESSION S WHERE KSMLRSIZ > 3000
AND A.ADDRESS=S.SQL_ADDRESS AND A.HASH_VALUE = S.SQL_HASH_VALUE
AND SADDR=KSMLRSES;
You can see the candidates to pin from the query below
COL STORED_OBJECT FORMAT A40;
COL SQ_EXECUTIONS FORMAT 999,999;
SELECT /*+ ORDERED USE_HASH(D) USE_HASH(C) */ O.KGLNAOWN||’.'||O.KGLNAOBJ STORED_OBJECT, SUM(C.KGLHDEXC) SQL_EXECUTIONS
FROM SYS.X$KGLOB O, SYS.X$KGLRD D, SYS.X$KGLCURSOR C
WHERE
O.INST_ID = USERENV(’INSTANCE’) AND
D.INST_ID = USERENV(’INSTANCE’) AND
C.INST_ID = USERENV(’INSTANCE’) AND
O.KGLOBTYP IN (7, 8, 9, 11, 12) AND
D.KGLHDCDR = O.KGLHDADR AND
C.KGLHDPAR = D.KGLRDHDL
GROUP BY O.KGLNAOWN, O.KGLNAOBJ
HAVING SUM(C.KGLHDEXC) > 0
ORDER BY 2 DESC;
How to pin object
EXECUTE SYS.DBMS_SHARED_POOL.SIZES(150);
EXECUTE SYS.DBMS_SHARED_POOL.KEEP('SYS.STANDARD');
EXECUTE SYS.DBMS_SHARED_POOL.UNKEEP('SYS.STANDARD');
e.LRU work and objects were loaded and flushed
LRU work in the shared pool KSMLRNUM stores the number of objects that were flushed to load the large object. KSMLRISZ stores the size of the object that was loaded (contiguous memory allocated)
column ksmlrcom format a20
column username format a5
select username,sid,KSMLRCOM,KSMLRSIZ,KSMLRNUM, KSMLRHON, KSMLROHV, KSMLRSES from x$ksmlru , v$session where KSMLRSES=SADDR and KSMLRNUM >2 ;
f.How much are waiting for Library Cache Latch
select count(*),event from v$session_wait where event not like '%SQL%' and event not like '%ipc%' and event not like '%timer%' GROUP BY EVENT;
select count(*),wait_time from v$session_wait where event='latch free' and p2=106 group by wait_time;
select sid,wait_time,seconds_in_wait from v$session_wait where event='latch free' and p2=106 and WAIT_TIME>1;
g.Queries identical but aren’t shared.
SELECT address, hash_value, version_count , users_opening , users_executing,
substr(sql_text,1,240) "SQL" FROM v$sqlarea WHERE version_count > 10;
h.Get Biggest chunk of free memory.
select sysdate, decode( sign(ksmchsiz - 812), -1, (ksmchsiz - 16) / 4,
decode(sign(ksmchsiz - 4012),-1, trunc((ksmchsiz + 11924) / 64),
decode(sign(ksmchsiz - 65548), -1, trunc(1/log(ksmchsiz - 11, 2)) + 238,254))) bucket,
sum(ksmchsiz) free_space, count(*) free_chunks, trunc(avg(ksmchsiz)) average_size,
max(ksmchsiz) biggest from x$ksmsp
where inst_id = userenv('Instance') and ksmchcls = 'free' group by
decode(sign(ksmchsiz - 812),-1, (ksmchsiz - 16) / 4,
decode(sign(ksmchsiz - 4012),-1, trunc((ksmchsiz + 11924) / 64),
decode(sign(ksmchsiz - 65548),-1, trunc(1/log(ksmchsiz - 11, 2)) + 238,254 ))) ;
SELECT KSMCHCLS CLASS, COUNT(KSMCHCLS) NUM, SUM(KSMCHSIZ) SIZ,
To_char( ((SUM(KSMCHSIZ)/COUNT(KSMCHCLS)/1024)),’999,999.00′)||’k’ “AVG SIZE”
FROM X$KSMSP GROUP BY KSMCHCLS;
CLASS NUM SIZ AVG SIZE
freeabl 19010 34519404 1.77k
recr 23581 24967956 1.03k
R-freea 68 1632 .02k
perm 22 39801268 1,766.75k
R-free 34 7238192 207.90k
free 2389 36075980 14.75k
Watch for trends using these guidelines:
a) if ‘free’ memory is low (less than 5mb or so) you may need to increase the shared_pool_size and shared_pool_reserved_size. You should expect ‘free’ memory to increase and decrease over time. Seeing trends where ‘free’ memory decreases consistently is not necessarily a problem, but seeing consistent spikes up and down could be a problem.
b) if ‘freeable’ or ‘perm’ memory continually grows then it is possible you are seeing a memory bug.
c) if ‘freeabl’ and ‘recr’ memory classes are always huge, this indicates that you have a lot of cursor info stored that is not releasing.
d) if ‘free’ memory is huge but you are still getting 4031 errors, the problem is likely reloads and invalids in the library cache causing fragmentation.
-Note says that this query can hang database on HP platforms
See the shared pool parameters
column name format a30
select name,value from v$parameter where name like '%shared_pool%' ;
select x.ksppinm, y.ksppstvl from x$ksppi x , x$ksppcv y where x.indx = y.indx and lower(x.ksppinm) like '%spin%';
SELECT count(*) FROM v$latch_children WHERE NAME = 'library cache';
Shrinking and growing operations from V$SGA_RESIZE_OPS dynamic view:
select to_char(end_time, ‘dd-Mon-yyyy hh24:mi’) end, oper_type, initial_size, target_size, final_size from V$SGA_RESIZE_OPS where component=’shared pool’ order by end;
#shared_pool_summary.sql -get an overview of chunks in the shared pool
select
ksmchcom contents,
count(*) chunks,
sum(decode(ksmchcls, 'recr', ksmchsiz)) recreatable,
sum(decode(ksmchcls, 'freeabl', ksmchsiz)) freeable,
sum(ksmchsiz) total
from
sys.x_$ksmsp
where
inst_id = userenv('Instance') and
ksmchcls not like 'R%'
group by
ksmchcom
#reserved_pool_summary.sql - get an overview of chunks in the reserved pool
select
ksmchcom contents,
count(*) chunks,
sum(decode(ksmchcls, 'R-recr', ksmchsiz)) recreatable,
sum(decode(ksmchcls, 'R-freea', ksmchsiz)) freeable,
sum(ksmchsiz) total
from
sys.x_$ksmspr
where
inst_id = userenv('Instance')
group by
ksmchcom
#save_sqlplus_settings.sql -reset sqlplus settings
set termout off
store set sqlplus_settings replace
clear breaks
clear columns
clear computes
set feedback off
set verify off
set termout on
set define "&"
#restore_sqlplus_settings.sql -reset sqlplus settings
set termout off
@sqlplus_settings
clear breaks
clear columns
clear computes
set termout on
i.Check the shared pool reserved size status
SELECT free_space, avg_free_size, used_space, avg_used_size, REQUEST_MISSES, request_failures, last_miss_size FROM v$shared_pool_reserved;
An ORA-04031 error referencing large failed requests, indicates the Reserved Area is too fragmented. The reserved pool is small when: REQUEST_FAILURES > 0 (and increasing), The DBA should Increase shared_pool_reserved_size and shared_pool_size together. It is possible that too much memory has been allocated to the reserved list. The DBA should Decrease shared_pool_reserved_size, If: REQUEST_MISS = 0 or not increasing
FREE_MEMORY = > 50% of shared_pool_reserved_size minimum
col free_space for 999,999,999,999 head “TOTAL FREE”
col avg_free_size for 999,999,999,999 head “AVERAGE|CHUNK SIZE
col free_count for 999,999,999,999 head “COUNT”
col request_misses for 999,999,999,999 head “REQUEST|MISSES
col request_failures for 999,999,999,999 head “REQUEST|FAILURES”
col max_free_size for 999,999,999,999 head “LARGEST CHUNK”
select free_space, avg_free_size, free_count, max_free_size, request_misses, request_failures from v$shared_pool_reserved;
TOTAL FREE AVERAGE
CHUNK SIZE COUNT LARGEST CHUNK REQUEST
MISSES REQUEST
FAILURES
7,238,192 212,888 34 212,888 0 0
You should also use hidden and unsupported parameter “_shared_pool_reserved_pct” to control reserved pool. This parameter controls the allocated percentage of shared pool for reserved pool. By default it is %5 of the shared pool and if you use ASMM for memory management you can set this value higher like 10 to allocate reserved pool dynamically. When you set the parameter you will see the shared_pool_reserved_size parameter will be adjusted to the new setting. The parameter can not be modified when instance is started. You can use the query below to see the current value
select a.ksppinm “Parameter”, b.ksppstvl “Session Value”, c.ksppstvl “Instance Value” from sys.x$ksppi a, sys.x$ksppcv b, sys.x$ksppsv c where a.indx = b.indx and a.indx = c.indx and a.ksppinm = ‘_shared_pool_reserved_pct’;
Parameter Session Value Instance Value
sharedpool_reserved_pct 10 10
j.When having multiple subheaps:
select KSMCHIDX, ksmchcom ChunkComment,
decode(round(ksmchsiz/1000),0,'0-1K', 1,'1-2K', 2,'2-3K', 3,'3-4K',4,'4-5K',5,'5-6k',6,'6-7k',7,'7-8k',8,'8-9k', 9,'9-10k', '> 10K'), count(*), ksmchcls Status, sum(ksmchsiz) Bytes
from x$ksmsp where KSMCHCOM = 'free memory' group by KSMCHIDX,ksmchcom, ksmchcls, decode(round(ksmchsiz/1000),0,'0-1K', 1,'1-2K', 2,'2-3K', 3,'3-4K',4,'4-5K',5,'5-6k',6,'6-7k',7,'7-8k',8,'8-9k', 9,'9-10k','> 10K');
SubPool SGA_HEAP CHUNKCOMMENT size COUNT(*) STATUS BYTES
1 sga heap(1,0) free memory > 10K 34 R-free 7238192
1 sga heap(1,0) free memory 3-4K 2 free 6284
1 sga heap(1,0) free memory > 10K 241 free 35707400
1 sga heap(1,0) free memory 8-9k 1 free 7712
1 sga heap(1,0) free memory 2-3K 4 free 6752
1 sga heap(1,0) free memory 0-1K 2090 free 133288
1 sga heap(1,0) free memory 9-10k 21 free 188676
1 sga heap(1,0) free memory 1-2K 30 free 25868
If you see lack of large chunks it is possible that you can face with ORA-04031 in near future.
k.Check shared pool at first glance quick diagnostics
select 'You may need to increase the SHARED_POOL_RESERVED_SIZE' Description, 'Request Failures = '||REQUEST_FAILURES Logic
from v$shared_pool_reserved where REQUEST_FAILURES > 0
and 0 != (select to_number(VALUE) from v$parameter
where NAME = 'shared_pool_reserved_size')
union
select 'You may be able to decrease the SHARED_POOL_RESERVED_SIZE' Description,'Request Failures = '||REQUEST_FAILURES Logic
from v$shared_pool_reserved where REQUEST_FAILURES < 5
and 0 != (select to_number(VALUE) from v$parameter
where NAME = 'shared_pool_reserved_size')
l.Memory Usage - object list level view
• Owner - Owner of the object
• Object - Name/namespace of the object
• Sharable Memory - Amount of sharable memory in the shared pool consumed by the object
select OWNER, NAME||' - '||TYPE object,SHARABLE_MEM
from v$db_object_cache where SHARABLE_MEM > 10000
and type in ('PACKAGE','PACKAGE BODY','FUNCTION','PROCEDURE')
order by owner asc ,SHARABLE_MEM desc
SELECT * FROM (SELECT ROW_NUMBER () over (PARTITION BY NAMESPACE ORDER BY SHARABLE_MEM DESC) ROW_within , NAMESPACE, SHARABLE_MEM, SUBSTR(NAME,1,40) NAME FROM V$DB_OBJECT_CACHE ORDER BY SHARABLE_MEM DESC) WHERE ROW_WITHIN <= 2 ORDER BY NAMESPACE, ROW_WITHIN;
ROW_WITHIN NAMESPACE SHARABLE_MEM NAME
1 CLUSTER 2794 C_OBJ#_INTCOL#
2 CLUSTER 1684 SMON_SCN_TO_TIME
1 RSRCPLAN 5117 SYS_GROUP -
HI,
I have a question our DB is showing Parse CPU to Parse Elapsd %: is very less 8.37. .
What should be done to overcome this problem....
actually we are facing a latch free wait event.....iand i have also identofy hot blocks....but i donlt know waht should be the next step...
can anybody suggest Pase CPU to Parse elapsedWhen i execute the V$latch_children
I found that today is also greates no. of sleeps is CACHE BUFFE LRY CHAINS
LATCH# NAME
GETS MISSES SLEEPS
50 ges resource hash list
601847 24245 22350
50 ges resource hash list
617442 24184 22367
50 ges resource hash list
749689 23959 22403
LATCH# NAME
GETS MISSES SLEEPS
50 ges resource hash list
612959 24281 22460
50 ges resource hash list
753679 24146 22491
50 ges resource hash list
610225 24510 22550
LATCH# NAME
GETS MISSES SLEEPS
50 ges resource hash list
605734 24468 22570
50 ges resource hash list
751314 24771 23073
157 library cache
342286141 281771 25970
LATCH# NAME
GETS MISSES SLEEPS
157 library cache
280560658 329228 31768
156 shared pool
463957862 289795 49417
118 KCL gc element parent latch
328364965 438291 51954
LATCH# NAME
GETS MISSES SLEEPS
118 KCL gc element parent latch
443999194 772076 91141
120 KCL freelist parent latch
909808383 2092535 128985
120 KCL freelist parent latch
903524925 2097603 136115
LATCH# NAME
GETS MISSES SLEEPS
93 cache buffers lru chain
617430181 2728584 382138
9568 rows selected.SQL> spool off
I am really finding difficult to post my query here..... -
Correct SGA size in hpux 24gb?
Hi guys...
We have a problemen with performance and a lot of type of latches latch: cache buffers chains.
We have an hpux server with 24gb and 8 procesors.
this is the parameters on DB.
Total System Global Area 4798283776 bytes
Fixed Size 2075600 bytes
Variable Size 2583692336 bytes
Database Buffers 2164260864 bytes
Redo Buffers 48254976 bytes
log_buffer integer 47511552
shared_pool_reserved_size big integer 200M
shared_pool_size big integer 2064M
But the problem of latches persist in hard hour of work, I hope someone have some tips to resizing memory.
best regards."We have a problemen with performance and a lot of type of latches latch: cache buffers chains."
check for hot blocks through v$latch, v$latch_children and v$bh (high TCH).
hot blocks are typically index root blocks or small tables.
strategies can be to increase pct_free to a very large value, forcing the introduction of more blocks so that latching is not located on a single buffer cache chain latch.
or
move the hot block to a separate buffer pool.
or
have the application code rewritten (cache locally). -
Hello guys,
i am a little bit confused about setting sga_target and sizing log_buffer manually.
At first the documentation:
http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14237/initparams192.htm#sthref792
The following pools are manually sized components and are not affected by Automatic Shared Memory Management:
* Log buffer
* Other buffer caches, such as KEEP, RECYCLE, and other block sizes
* Fixed SGA and other internal allocations
Ok.. now my Oracle 10gR2 database:
- spfile:
*.log_buffer=1048576
*.sga_target=3154116608
Ok now in my opinion, the log_buffer should not be changed by oracle AMM.
So lets have a look:
SQL> show parameter log_buffer
NAME TYPE VALUE
log_buffer integer 14254080
SQL> show sga
Total System Global Area 3154116608 bytes
Fixed Size 2074600 bytes
Variable Size 603981848 bytes
Database Buffers 2533359616 bytes
Redo Buffers 14700544 bytes
Oh ok.... why does oracle change my manually sized value log_buffer from 1MB up to 14MB!!! (have a look at the output of show sga!)
Hmm and now?
What is right and what is wrong?
Maybe someone can clear the confusion...
Thanks and Regards
StefanHi Satheesh,
this forum is amazing :-)
But... i try to calculate like your information:
So have a look at my test database:
SQL> show sga
Total System Global Area 2097152000 bytes
Fixed Size 2072576 bytes
Variable Size 520093696 bytes
Database Buffers 1560281088 bytes
Redo Buffers 14704640 bytes
SQL> show parameter log_buffer
NAME TYPE VALUE
log_buffer integer 14258176
The lgwr.trc shows:
Maximum redo generation record size = 132096 bytes
Maximum redo generation change vector size = 124412 bytes
And the table entry:
SQL> select name, count(*) from v$latch_children where name='redo allocation' group by name;
NAME COUNT(*)
redo allocation 2
Ok and now 132096 bytes * 2 = 264192 bytes... and not 14704640 bytes like in show sga or parameter log_buffer.
Regards
Stefan -
Hi All,
Can you please educate me on below things. Also, please correct me if i am wrong
1.
db_writer_processes controls number of db writers that are been started when instance is initialized. So, once DB is up lets say we have 6 dbwriter process then your buffer cache is splitted in 6 working data sets. Can you please explain what is this datasets are ? or may be if i am wrong .
2.
If so this is true how can we find that which dataset is used by which dbwrite processes. I mean how to find one to one mapping for say 0x address- to 0y address is been worked by dbwr1 process and so on. how to find this
3.
If we have multiple buffer cache like db_16k and db_32k then how do we map this.
Reason behind this we are using 12 dbwriter process for we have 12gb of sga and 10gb of pga. Some time we are getting buffer busy waits. So, need to find that we are using multiple buffer pools. So, if it is from there then i can suggest management to use only default block size and not multiple. I already know that multiple buffer pool have overhead of managing one more memory structure so need to investigate and learn from you.
My idea is to reduce this and then start adding processes if necessaryHi Jonathan,
Thank you very much so here are the things which we can conclude from this. Please correct me if i am wrong as i am new to this whole thing.
1.
Excessive db writer processes can be overhead due to each working set requires it's own db lru latches.
2.
Excessive db writer processes can slow down I/O due to they need to acquire CPU and then run. But one question here is does all db writer process simultinouses compete for cpu or it waits for one to complete and then go to other cpu. As, i can understand cpu uses serialize mechanism but lets say we have 12 dbwriter among one is writing using one cpu and other cpu is free. So, other process can move to that or db writer process is also serial ?
3.
Also, this can lead to wrong buffer waits situation as we can have free buffer in other sets and in one set it won't and process acquire that dbwriter so that it will post this wait event but actually we have other free buffers available. How to find this as how many buffers are available, dirty or in other state for each working set ?
4.
NAME TYPE VALUE
db_32k_cache_size big integer 32M
So, it means that for 32MB scanning of memory we need 12 data working sets or this 32k block size dbwriter data sets can be used by 16k also ?
And here is the output from our environment
SQL> select bfp.bp_blksz,
bfp.bp_name,
bfp.bp_size,
wds.indx wds_index,
wds.dbwr_num,
wds.FBWAIT,
wds.BBWAIT,
wds.set_latch,
l.gets,
l.MISSES,
l.SLEEPS
from x$kcbwbpd bfp, x$kcbwds wds, v$latch_children l
where bfp.bp_size != 0
and wds.set_id between bfp.bp_lo_sid and bfp.bp_hi_sid
and l.ADDR = wds.set_latch
order by bfp.bp_blksz, bfp.bp_name, wds.indx;
BP_BLKSZ BP_NAME BP_SIZE WDS_INDEX DBWR_NUM FBWAIT BBWAIT SET_LATCH GETS MISSES SLEEPS
16384 DEFAULT 370845 24 0 8753 6822 000000053D44E478 2088984 724 39
16384 DEFAULT 370845 25 1 8721 7027 000000053D44E9D0 2093594 962 29
16384 DEFAULT 370845 26 2 8543 4382 000000053D44EF28 2491595 962 29
16384 DEFAULT 370845 27 3 7907 4836 000000053D44F480 2155756 1042 43
16384 DEFAULT 370845 28 4 7655 5722 000000053D44F9D8 2131806 978 30
16384 DEFAULT 370845 29 5 7270 4440 000000053D44FF30 2117001 1074 34
16384 DEFAULT 370845 30 6 8350 2804 000000053D450488 2087645 930 35
16384 DEFAULT 370845 31 7 7841 6987 000000053D4509E0 2145802 908 37
16384 DEFAULT 370845 32 8 8699 4890 000000053D450F38 2119788 928 35
16384 DEFAULT 370845 33 9 8074 4679 000000053D451490 2167632 925 29
16384 DEFAULT 370845 34 10 8666 5068 000000053D4519E8 2103990 902 27
16384 DEFAULT 370845 35 11 12503 7753 000000053D451F40 2150953 991 38
BP_BLKSZ BP_NAME BP_SIZE WDS_INDEX DBWR_NUM FBWAIT BBWAIT SET_LATCH GETS MISSES SLEEPS
32768 DEFAULT 1012 84 0 11205160 11401610 000000053D462518 37611275 129971 1188
32768 DEFAULT 1012 85 1 9643066 11547834 000000053D462A70 36582915 106640 1157
32768 DEFAULT 1012 86 2 10446003 11583563 000000053D462FC8 37427372 102028 1088
32768 DEFAULT 1012 87 3 10573808 11563144 000000053D463520 37295902 104804 1058
32768 DEFAULT 1012 88 4 10408529 11452657 000000053D463A78 37088311 102178 1169
32768 DEFAULT 1012 89 5 10339793 11544617 000000053D463FD0 37020968 102712 1097
32768 DEFAULT 1012 90 6 10385856 11522059 000000053D464528 37197322 101601 1084
32768 DEFAULT 1012 91 7 10379007 11495563 000000053D464A80 37131610 99125 982
32768 DEFAULT 1012 92 8 10388032 11491618 000000053D464FD8 37119317 100206 1081
32768 DEFAULT 1012 93 9 10437875 11557976 000000053D465530 37188171 100933 1108
32768 DEFAULT 1012 94 10 10004858 11523490 000000053D465A88 36865058 89088 1075
32768 DEFAULT 1012 95 11 11481299 11509310 000000053D465FE0 38390757 127075 1088
24 rows selected.Edited by: Taral Desai on Jun 4, 2009 1:25 PM -
High CPU load with Library Cache Pin wit event.
Oracle8i Enterprise Edition Release 8.1.6.0.0, 64 bit - Production
HP-UX B.11.00 U 9000/800 605309363 unlimited-user license
Currently CPU load is 100% with very less sessions in the database.
But i am finding Library Cache Pin wait event in top.
If i query v$latchholder i am not getting any rows..and in v$lacth_children
SQL> select SID,EVENT,WAIT_TIME,SECONDS_IN_WAIT,STATE from v$session_wait where EVENT='library cache pin';
SID EVENT WAIT_TIME SECONDS_IN_WAIT STATE
8 library cache pin 0 863 WAITING
90 library cache pin 0 3093 WAITING
89 library cache pin 0 2566 WAITING
57 library cache pin 0 27384 WAITING
54 library cache pin 0 21029 WAITING
53 library cache pin 0 7840 WAITING
50 library cache pin 0 2620 WAITING
47 library cache pin 0 6031 WAITING
46 library cache pin 0 1241 WAITING
41 library cache pin 0 15637 WAITING
145 library cache pin 0 910 WAITING
133 library cache pin 0 5124 WAITING
111 library cache pin 0 15077 WAITING
98 library cache pin 0 6563 WAITING
94 library cache pin 0 2088 WAITING
93 library cache pin 0 4592 WAITING
92 library cache pin 0 14705 WAITING
91 library cache pin 0 14798 WAITING
36 library cache pin 0 1533 WAITING
33 library cache pin 0 1491 WAITING
28 library cache pin 0 13970 WAITING
25 library cache pin 0 7630 WAITING
11 library cache pin 0 12169 WAITING
12 library cache pin 0 2352 WAITING
14 library cache pin 0 19748 WAITING
SQL> select addr,name from v$latch where name='library cache';
ADDR NAME
C00000006971D460 library cache
SQL> select latch#,name from v$latch_children where name='library cache';
LATCH# NAME
105 library cache
105 library cache
105 library cache
105 library cache
105 library cachePlease help me out to find actual cause of these latches and fix ?
-Yasserbump
No-one?
The problem seems to have 'resolved itself' over the weekend incidentally (although I don't believe anything truly resolves itself in this manner - something must have changed). -
Hi,
Kindly tell me concepts of hot block in oracle database
Thanks
DeepakDeepak,
Usually, when someone talks about "hot blocks" they mean blocks that are very popular and are requested so often that the competition between users that want to access the blocks start to cause performance issues.
There are two typical symptoms of hot blocks.
a) buffer busy waits. If there is a lot of competition between many users to modify the same block(s) very frequently, then they have to compete for exclusive access to the block because only one user is alowed to change a block at a time.
b) increased activity on the 'cache buffers chains' latches. Even if a user is only trying to view the contents of a block, they still have to do some work to find the block and make sure it stays in memory for a while. To do this, the user has to acquire the relevant 'cache buffers chains' latch - so if there are lots of sessions constantly trying to read the same block, then there will be competition for the one relevant latch. (This, particularly, is why Francisco has introduced a script that accesses v$latch_children).
If you don't see any indications of significant time lost on wait event 'buffer busy waits', or any extreme numbers of get, misses, or sleeps on individual 'cache buffers chains' latches, then you probably have more important things to worry about than hot blocks.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge." (Stephen Hawking)
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