SQL - Highest Physical Reads
Dear Experts,
I want to find out the query (sql id) that contributed to highest number of physical reads over a 24 hours period (snap id's 1 to 24) by a specific user - 'USER'
I'm using query as below, don't think it's giveing me right..any suggestions pls
select sql_id, PHYSICAL_READ_BYTES_DELTA from DBA_HIST_SQLSTAT
where PARSING_SCHEMA_NAME = 'USER' and snap_id between 1 and 24 order by PHYSICAL_READ_BYTES_DELTA;
You can try this
select substr(sql_text,1,500) "SQL",
(cpu_time/1000000) "CPU_Seconds",
disk_reads "Disk_Reads",
buffer_gets "Buffer_Gets",
executions "Executions",
case when rows_processed = 0 then null
else round((buffer_gets/nvl(replace(rows_processed,0,1),1)))
end "Buffer_gets/rows_proc",
round((buffer_gets/nvl(replace(executions,0,1),1))) "Buffer_gets/executions",
(elapsed_time/1000000) "Elapsed_Seconds",
module "Module"
from v$sql s
order by disk_reads desc nulls lastYou can get this from the SQL DEveloper --reports-database administration-Topsql-diskreads
Similar Messages
-
Top 10 SQL's by Physical reads
Dear experts,
Oracle version - 11.1.0.7
Do we have a way to pull top 10 SQL's (physical reads) for a 24 hour period based on AWR data or other V$ views.
ThanksFrom DBA_HIST_SQLSTAT, all you can tell is who the parsing user was.
Not the executing user.
So for queries which are executed multiple times by multiple users, DBA_HIST_SQLSTAT is insufficient and there's no great solution.
You could have a look in the underlying ASH data - V$ACTIVE_SESSION_HISTORY and DBA_HIST_ACTIVE_SESS_HISTORY which is respectively sampled data and a sample of a sample and it might give an indication of who is executing.
Edited by: Dom Brooks on Jul 19, 2012 10:18 AM
Part of sentence was missing -
AWR Report - Tablespace physical I/O doesn't compute to SQL Physical reads
I am trying to track Disk I/O issues. I have AWR report that shows total disk reads to be 35M+. However in the Tablespace IO section there is barely 2M disk reads. Why do the number not match a bit more closely.
The SAN used is a EMC DMX3 system with 80GB of cache.
Any insight appreciated.
ChrisSlight correction the 35M+ reads was from the "SQL Ordered by Reads" section. The 2M was for the Tbalespace IO section.
Sorry for any confusion.
Chris -
Logical SQL to physical SQL in datamodel.
I am designing a report in BI publisher and for that I am creating a datamodel.
My datamodel contains 4 dataset with 4 different logical SQLs and all use source as Oracle BIEE.
When I generate/execute xml from datamodel I observed in nqquery.log that BI publisher is executing each logical SQL in sequence.
That is OBIEE first send logical SQL of one of the dataset and then convert it to physical SQL. After first physical SQL is completed then only it is converting second logical SQL to physical.
So logical to physical query is happening in sequence rather than in parallel.
My datamodel contains huge logical SQLs and OBIEE takes almost 40 seconds each to convert it physical query. This will result in total 160 seconds for just converting 4 logical SQLs to physical SQLs.
Does anybody know if there is any setting where I can manage to convert multiple logical to physical in parallel?Hi Experts,
Please help on this. -
What causes BUFFER GETS and PHYSICAL READS in INSERT operation to be high?
Hi All,
Am performing a huge number of INSERTs to a newly installed Oracle XE 10.2.0.1.0 on Windows. There is no SELECT statement running, but just INSERTs one after the other of 550,000 in count. When I monitor the SESSION I/O from Home > Administration > Database Monitor > Sessions, I see the following stats:
BUFFER GETS = 1,550,560
CONSISTENT GETS = 512,036
PHYSICAL READS = 3,834
BLOCK CHANGES = 1,034,232
The presence of 2 stats confuses. Though the operation is just INSERT in database for this session, why should there be BUFFER GETS of this magnitude and why should there by PHYSICAL READS. Aren't these parameters for read operations? The BLOCK CHANGES value is clear as there are huge writes and the writes change these many blocks. Can any kind soul explain me what causes there parameters to show high value?
The total columns in the display table are as follows (from the link mentioned above)
1. Status
2. SID
3. Database Users
4. Command
5. Time
6. Block Gets
7. Consistent Gets
8. Physical Reads
9. Block Changes
10. Consistent Changes
What does CONSISTENT GETS and CONSISTENT CHANGES mean in a typical INSERT operation? And does someone know which all tables are involved in getting these values?
Thank,
...Flake wrote:
Hans, gracias.
The table just have 2 columns, both of which are varchar2 (500). No constraints, no indexes, neither foreign key references are in place. The total size of RAM in system is 1GB, and yes, there are other GUI's going on like Firefox browser, notepad and command terminals.
But, what does these other applications have to do with Oracle BUFFER GETS, PHYSICAL READS etc.? Awaiting your reply.Total RAM is 1GB. If you let XE decide how much RAM is to be allocated to buffers, on startup that needs to be shared with any/all other applications. Let's say that leaves us with, say 400M for the SGA + PGA.
PGA is used for internal stuff, such as sorting, which is also used in determing the layout of secondary facets such as indexes and uniqueness. Total PGA usage varies in size based on the number of connections and required operations.
And then there's the SGA. That needs to cover the space requirement for the data dictionary, any/all stored procedures and SQL statements being run, user security and so on. As well as the buffer blocks which represent the tablespace of the database. Since it is rare that the entire tablespace will fit into memory, stuff needs to be swapped in and out.
So - put too much space pressure on the poor operating system before starting the database, and the SGA may be squeezed. Put that space pressure on the system and you may enbd up with swapping or paging.
This is one of the reasons Oracle professionals will argue for dedicated machines to handle Oracle software. -
Consistent gets and physical reads
Hi all,
I am tuning a DM SQL query, by comparing execution plans with STAR TRANSFORMATION enabled or disabled. I got the following results:
STAR TRANSFORMATION ON
74889 consistent gets
254365 physical reads
STAR TRANSFORMATION OFF
1945892 consistent gets
168028 physical reads
I thought a physical read would be counted as a logical read as well, because the data block would be read from disk (1 physical IO), placed in the buffer cache and then read from there (1 more logical IO or consistent get).
So, one physical IO does not cause a logical IO?
Thanks!
Edited by: user10634835 on 12-Jul-2011 08:40But shouldn't consistent gets be >= physical reads (Since, as per my understanding, 1 PIO causes at least 1 LIO)? In this case it is not.
74889 consistent gets
254365 physical readsJust clarifying for my knowledge.
regards -
OBIEE: logical SQL to Physical sql conversion
Hi,
Is there any way i can get the physical sql from logical sql ( Apart from reading log file).. I am looking something like JAVA api which does that for us.. Do we have any mapping table which stores this mapping.
Does the OBIEE provides any Java API.
Appreciate your help in advance.Hi Experts,
Please help on this. -
Logical SQL to physical SQL taking time in datamodel.
I am designing a report in BI publisher and for that I am creating a datamodel.
My datamodel contains 4 dataset with 4 different logical SQLs and all use source as Oracle BIEE.
When I generate/execute xml from datamodel I observed in nqquery.log that BI publisher is executing each logical SQL in sequence.
That is OBIEE first send logical SQL of one of the dataset and then convert it to physical SQL. After first physical SQL is completed then only it is converting second logical SQL to physical.
So logical to physical query is happening in sequence rather than in parallel.
My datamodel contains huge logical SQLs and OBIEE takes almost 40 seconds each to convert it physical query. This will result in total 160 seconds for just converting 4 logical SQLs to physical SQLs.
Does anybody know if there is any setting where I can manage to convert multiple logical to physical in parallel?Hi Experts,
Please help on this. -
Query on data dictionary results in large number of physical reads
I don't understand why I am getting 80,000 physicals for this query. I am not looking for help re-writing this. I just don't understand why I would hit the disk at all.
My understanding had been that v$views where sql structures that pointed to x$tables. These x$tables are sql structures.
underneath, the x$tables were linked lists stored in memory. This is why when you bounce the database, all the data, gets reset. Since it is not saved to disk.
I am doing a simple insert/select off of v$open_cursor that is resulting in 80,000+ physical reads. I am posting the tkprof. It is all from v$open_cursor.
mysid_table has 6 records. It is 1 mb in size
if I index mysid_table.sid the query reduces to 20,000 physical reads. (but all the physical reads are on v$session_event)
the sequence number I am passing returns 2 SIDs
insert into my_save_table
select *
from v$session_event
where sid in (select sid
from my_sid_table
where id = vseq);
vrowcount := sql%rowcount;
call count cpu elapsed disk query current rows
Parse 1 0.01 0.01 0 0 0 0
Execute 1 31.70 47.57 88570 22 0 1
Fetch 0 0.00 0.00 0 0 0 0
total 2 31.71 47.58 88570 22 0 1
Misses in library cache during parse: 1
Optimizer mode: CHOOSE
Parsing user id: 22
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
latch: row cache objects 1 0.00 0.00
log file sync 1 0.00 0.00
SQL*Net message to client 1 0.00 0.00
SQL*Net message from client 1 0.00 0.00
********************************************************************************It seems like there is some missing information.
You have a wait for a log file sync, but no commit.
Your table my_sid_table is 1 MB for only 6 records?
Does the target table you are inserting into (my_save_table) have indexes on it? -
High no. of physical reads of a query in statspack report
we have a Oracle database 9.2.0.6 on solaris box....
SQL ordered by Reads for DB: ic Instance: ic12 Snaps: 19 -20
-> End Disk Reads Threshold: 1000
CPU Elapsd
Physical Reads Executions Reads per Exec %Total Time (s) Time (s) Hash Value
1,103,253 77 14,328.0 53.1 1641.98 11428.17 3825541888
Module: w3wp.exe
select MRH_MRN,DECODE(MRH_SEX,'M','MALE','FEMALE') AS SEX, trim
((mrh_sur_name||' '||mrh_first_name||' '||mrh_middle_name)) as M
EMNAME, decode(nvl(mrh_fellow_status_yn,'333'),'Y','FCA','ACA')
AS ACA_FCA, DECODE(MRH_RESI_STATUS,'I',MRH_PROF_ADDR_LINE_1,'A',
MRH_RES_ADDR_LINE_1) AS L_ADD1, DECODE(MRH_RESI_STATUS,'I',MRH_Pexplain plan
SQL> explain plan for select MRH_MRN,DECODE(MRH_SEX,'M','MALE','FEMALE') AS SEX
, trim((mrh_sur_name||' '||mrh_first_name||' '||mrh_middle_name)) as MEMNAME, de
code(nvl(mrh_fellow_status_yn,'333'),'Y','FCA','ACA')AS ACA_FCA, DECODE(MRH_RESI
_STATUS,'I',MRH_PROF_ADDR_LINE_1,'A',
2 MRH_RES_ADDR_LINE_1) AS L_ADD1, DECODE(MRH_RESI_STATUS,'I',MRH_PROF_ADDR_LI
NE_2,'A',MRH_RES_ADDR_LINE_2) AS L_ADD2, DECODE(MRH_RESI_STATUS,'I',MRH_PROF_ADD
R_LINE_3,'A',MRH_RES_ADDR_LINE_3) ASL_ADD3, DECODE(MRH_RESI_STATUS,'I',MRH_PROF_
ADDR_LINE_4,'A',
3 MRH_RES_ADDR_LINE_4) AS L_ADD4, DECODE(MRH_RESI_STATUS,'I',a.city_name,'A',
C.CITY_NAME) AS L_CITY, DECODE(MRH_RESI_STATUS,'I',MRH_PROF_ZIP_POSTAL_CODE,'A',
MRH_RES_ZIP_POSTAL_CODE) AS L_PIN, DECODE(MRH_RESI_STATUS,'I',b.cou_name,'A',D.C
OU_NAME) as L_Country,
4 DECODE(MRH_RESI_STATUS,'I','NOT APPLICABLE',MRH_PROF_ADDR_LINE_1)AS R_ADD1,
DECODE(MRH_RESI_STATUS,'I',' ',MRH_PROF_ADDR_LINE_2)AS R_ADD2, DECODE(MRH_RESI_
STATUS,'I',' ',MRH_PROF_ADDR_LINE_3)
5 AS R_ADD3, DECODE(MRH_RESI_STATUS,'I',' ',MRH_PROF_ADDR_LINE_4)AS R_ADD4, D
ECODE(MRH_RESI_STATUS,'I',' ','A',A.CITY_NAME) AS R_CITY, DECODE(MRH_RESI_STATUS
,'I',' ','A',MRH_PROF_ZIP_POSTAL_CODE) AS R_PIN, DECODE(MRH_RESI_STATUS,'I',' ',
'A',B.COU_NAME) as
6 R_Country, decode(nvl(mrh_mem_sub_status,'555'),'26','EXPIRED','') as sub_s
tatus, decode(nvl(mrh_mem_status,'777'),'1','ACTIVE','2','REMOVED') as mem_statu
s,mrh_resi_status, DECODE(MRH_COP_STATUS,'1',DECODE(MRH_COP_TYPE ,'13','FULLTIME
-COP','1',
7 'FULLTIME-COP', '12','PARTTIME-COP','2','PARTTIME-COP'),'NOT HOLDING COP')
AS COP_STATUS, TO_CHAR(MRH_ENROL_DT,'RRRR') AS ASSO_YR,TO_CHAR(MRH_FELLOW_DT,'RR
RR') AS FELLOW_YR from om_mem_reg_head,om_city A,
8 om_country B,om_city C,om_country D where mrh_doc_status=5 and mrh_prof_
city_code=A.City_code(+) and mrh_prof_cou_code=B.cou_code(+) and mrh_res_city_c
ode=C.City_code(+) and mrh_res_cou_code=D.cou_code(+) and trim((mrh_sur_name||'
'||mrh_first_name||
9 ''||mrh_middle_name)) like upper('%%') ORDER BY trim((mrh_sur_name||' '||m
rh_first_name||' '||mrh_middle_name))
10 ;
Explained.
SQL> select * from table(dbms_xplan.displaY());
PLAN_TABLE_OUTPUT
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost
|
| 0 | SELECT STATEMENT | | 2870 | 762K| | 202
PLAN_TABLE_OUTPUT
8 |
| 1 | SORT ORDER BY | | 2870 | 762K| 1592K| 202
8 |
| 2 | NESTED LOOPS OUTER | | 2870 | 762K| | 190
2 |
| 3 | NESTED LOOPS OUTER | | 2870 | 714K| | 190
2 |
PLAN_TABLE_OUTPUT
| 4 | HASH JOIN OUTER | | 2870 | 667K| | 190
2 |
| 5 | HASH JOIN OUTER | | 2870 | 616K| | 189
2 |
| 6 | TABLE ACCESS FULL| OM_MEM_REG_HEAD | 2870 | 566K| | 188
2 |
| 7 | TABLE ACCESS FULL| OM_COUNTRY | 677 | 12186 | |
4 |
PLAN_TABLE_OUTPUT
| 8 | TABLE ACCESS FULL | OM_COUNTRY | 677 | 12186 | |
4 |
| 9 | INDEX UNIQUE SCAN | CITY_CODE_PK | 1 | 17 | |
|
| 10 | INDEX UNIQUE SCAN | CITY_CODE_PK | 1 | 17 | |
|
PLAN_TABLE_OUTPUT
Note: cpu costing is off, PLAN_TABLE' is old version
18 rows selected.
SQL>Please suggest me whjat cab done to overcome the same
Edited by: user00726 on Feb 3, 2009 5:03 AMSQL> show arraysize
arraysize 15
SQL>should i set SDU parameter in tnsnames and listener.ora
for more info related to the same...pls do visit the below thread:
n/w perfromance related problem -
Query tuning-how to reduce physical reads-help me
1* select * from masterbillingInvoiceview Where SiteIID =300964 and InvoiceID like '%' order by Invoice asc
SQL> /
33 rows selected.
Elapsed: 00:00:00.34
Execution Plan
Plan hash value: 352896138
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 16 | 6304 | 341 (3)| 00:00:05 |
| 1 | SORT ORDER BY | | 16 | 6304 | 341 (3)| 00:00:05 |
| 2 | TABLE ACCESS BY INDEX ROWID | ADDRESS | 1 | 48 | 2 (0)| 00:00:01
| 3 | NESTED LOOPS | | 16 | 6304 | 340 (3)| 00:00:05 |
| 4 | NESTED LOOPS | | 16 | 5536 | 316 (3)| 00:00:04 |
|* 5 | HASH JOIN OUTER | | 16 | 5168 | 308 (3)| 00:00:04 |
|* 6 | HASH JOIN | | 16 | 4992 | 302 (3)| 00:00:04 |
|* 7 | HASH JOIN | | 16 | 4752 | 298 (3)| 00:00:04 |
| 8 | NESTED LOOPS | | 17 | 4828 | 44 (0)| 00:00:01 |
| 9 | NESTED LOOPS | | 17 | 3451 | 35 (0)| 00:00:01 |
| 10 | NESTED LOOPS OUTER | | 1 | 91 | 2 (0)| 00:00:01 |
| 11 | TABLE ACCESS BY INDEX ROWID| SITEMASTER | 1 | 74 | 1 (0)| 00:00:01 |
|* 12 | INDEX UNIQUE SCAN | PK_SITEMASTER | 1 | | 1 (0)| 00:00:01 |
| 13 | TABLE ACCESS BY INDEX ROWID| INVGROUPS | 1735 | 29495 | 1 (0)| 00:00:01 |
|* 14 | INDEX UNIQUE SCAN | PK_INVGROUPS | 1 | | 1 (0)| 00:00:01 |
|* 15 | TABLE ACCESS BY INDEX ROWID | INVOICEHEAD | 17 | 1904 | 33 (0)| 00:00:01 |
|* 16 | INDEX RANGE SCAN | IDX_INVOICEHEADSITEIID | 271 | | 1 (0)| 00:00:01 |
| 17 | TABLE ACCESS BY INDEX ROWID | CUSTOMER | 1 | 81 | 1 (0)| 00:00:01 |
|* 18 | INDEX UNIQUE SCAN | PK_CUSTOMER | 1 | | 1 (0)| 00:00:01 |
| 19 | VIEW | | 35844 | 455K| 254 (3)| 00:00:04 |
| 20 | HASH GROUP BY | | 35844 | 455K| 254 (3)| 00:00:04 |
| 21 | TABLE ACCESS FULL | CONTACT | 56100 | 712K| 250 (1)| 00:00:03 |
| 22 | VIEW | index$_join$_009 | 7 | 105 | 3 (0)| 00:00:01 |
|* 23 | HASH JOIN | | | | | |
| 24 | INDEX FAST FULL SCAN | IDX_PAYMENTTERMSID | 7 | 105 | 1 (0)| 00:00:01
| 25 | INDEX FAST FULL SCAN | PK_PAYMENTTERMS | 7 | 105 | 1 (0)| 00:00:01
| 26 | VIEW | index$_join$_011 | 1428 | 15708 | 6 (0)| 00:00:01 |
|* 27 | HASH JOIN | | | | | |
| 28 | INDEX FAST FULL SCAN | PK_EMPLOYEE | 1428 | 15708 | 3 (0)| 00:00:01 |
| 29 | INDEX FAST FULL SCAN | IDX_EMPLOYEEEMPLOYEEID | 1428 | 15708 | 3 (0)| 00:00:01
| 30 | TABLE ACCESS BY INDEX ROWID | CONTACT | 1 | 23 | 1 (0)| 00:00:
|* 31 | INDEX UNIQUE SCAN | PK_CONTACT | 1 | | 1 (0)| 00:00:01 |
|* 32 | INDEX RANGE SCAN | PK_ADDRESS | 1 | | 1 (0)| 00:00:01 |
Predicate Information (identified by operation id):
5 - access("A"."CREATEDBY"="J"."EMPIID"(+))
6 - access("A"."TERMSIID"="H"."PAYMENTTERMSIID")
7 - access("D"."CUSTOMERIID"="F"."CUSTOMERIID")
12 - access("B"."SITEIID"=300964)
14 - access("B"."PARENTIID"="I"."GROUPIID"(+))
15 - filter("A"."TYPE"=4 AND "A"."INVOICEID" LIKE '%')
16 - access("A"."SITEIID"=300964)
18 - access("A"."BILLINGCUSTOMERIID"="D"."CUSTOMERIID")
23 - access(ROWID=ROWID)
27 - access(ROWID=ROWID)
31 - access("F"."CONTACTIID"="G"."CONTACTIID")
32 - access("E"."ADDRESSIID"=NVL("D"."BILLINGADDRESSIID","D"."ADDRESSIID"))
Statistics
107 recursive calls
0 db block gets
2819 consistent gets
0 physical reads
0 redo size
6586 bytes sent via SQL*Net to client
356 bytes received via SQL*Net from client
4 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
33 rows processed
SQL> ed
Wrote file afiedt.buf
1* select * from masterbillingInvoiceview Where SiteIID =300964 and InvoiceID like '%%%' order by Invoice asc
SQL> /
33 rows selected.
Elapsed: 00:06:15.23
Execution Plan
Plan hash value: 1828716447
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 2 | 964 | 295 (3)| 00:00:04 |
|* 1 | FILTER | | | | | |
| 2 | SORT GROUP BY | | 2 | 964 | 295 (3)| 00:00:04 |
| 3 | MERGE JOIN CARTESIAN | | 72315 | 33M| 291 (1)| 00:00:04 |
| 4 | TABLE ACCESS BY INDEX ROWID | ADDRESS | 1 | 52 | 2 (0)| 00:00:01 |
| 5 | NESTED LOOPS | | 1 | 447 | 41 (0)| 00:00:01 |
| 6 | NESTED LOOPS | | 1 | 395 | 40 (0)| 00:00:01 |
| 7 | NESTED LOOPS | | 1 | 382 | 38 (0)| 00:00:01 |
| 8 | NESTED LOOPS OUTER | | 1 | 289 | 37 (0)| 00:00:01 |
| 9 | NESTED LOOPS | | 1 | 266 | 36 (0)| 00:00:01 |
| 10 | NESTED LOOPS | | 1 | 239 | 35 (0)| 00:00:01 |
| 11 | NESTED LOOPS OUTER | | 1 | 115 | 2 (0)| 00:00:01 |
| 12 | TABLE ACCESS BY INDEX ROWID| SITEMASTER | 1 | 86 | 1 (0)| 00:00:01 |
|* 13 | INDEX UNIQUE SCAN | PK_SITEMASTER | 1 | | 1 (0)| 00:00:01 |
| 14 | TABLE ACCESS BY INDEX ROWID| INVGROUPS | 1735 | 50315 | 1 (0)| 00:00:01 |
|* 15 | INDEX UNIQUE SCAN | PK_INVGROUPS | 1 | | 1 (0)| 00:00:01 |
|* 16 | TABLE ACCESS BY INDEX ROWID | INVOICEHEAD | 1 | 124 | 33 (0)| 00:00:01 |
|* 17 | INDEX RANGE SCAN | IDX_INVOICEHEADSITEIID | 271 | | 1 (0)| 00:00:01 |
| 18 | TABLE ACCESS BY INDEX ROWID | PAYMENTTERMS | 1 | 27 | 1 (0)| 00:00:01 |
|* 19 | INDEX UNIQUE SCAN | PK_PAYMENTTERMS | 1 | | 1 (0)| 00:00:01 |
| 20 | TABLE ACCESS BY INDEX ROWID | EMPLOYEE | 1 | 23 | 1 (0)| 00:00:01 |
|* 21 | INDEX UNIQUE SCAN | PK_EMPLOYEE | 1 | | 1 (0)| 00:00:01 |
| 22 | TABLE ACCESS BY INDEX ROWID | CUSTOMER | 1 | 93 | 1 (0)| 00:00:01 |
|* 23 | INDEX UNIQUE SCAN | PK_CUSTOMER | 1 | | 1 (0)| 00:00:01 |
| 24 | TABLE ACCESS BY INDEX ROWID | CONTACT | 1 | 13 | 2 (0)| 00:00:01 |
|* 25 | INDEX RANGE SCAN | IDX_CONTACTCUSTOMERIID | 2 | | 1 (0)| 00:00:01 |
|* 26 | INDEX RANGE SCAN | PK_ADDRESS | 1 | | 1 (0)| 00:00:01 |
| 27 | BUFFER SORT | | 56100 | 1917K| 294 (3)| 00:00:04 |
| 28 | TABLE ACCESS FULL | CONTACT | 56100 | 1917K| 250 (1)| 00:00:03 |
Predicate Information (identified by operation id):
1 - filter("G"."CONTACTIID"=MAX("CONTACTIID"))
13 - access("B"."SITEIID"=300964)
15 - access("B"."PARENTIID"="I"."GROUPIID"(+))
16 - filter("A"."TYPE"=4 AND "A"."INVOICEID" LIKE '%%%')
17 - access("A"."SITEIID"=300964)
19 - access("A"."TERMSIID"="H"."PAYMENTTERMSIID")
21 - access("A"."CREATEDBY"="J"."EMPIID"(+))
23 - access("A"."BILLINGCUSTOMERIID"="D"."CUSTOMERIID")
25 - access("D"."CUSTOMERIID"="CUSTOMERIID")
filter("CUSTOMERIID" IS NOT NULL)
26 - access("E"."ADDRESSIID"=NVL("D"."BILLINGADDRESSIID","D"."ADDRESSIID"))
Statistics
1952 recursive calls
78 db block gets
4649 consistent gets
236151 physical reads
0 redo size
6586 bytes sent via SQL*Net to client
356 bytes received via SQL*Net from client
4 SQL*Net roundtrips to/from client
1 sorts (memory)
1 sorts (disk)
33 rows processed
this is the execution plan of my one query with a small difference, bt there is large diffference in physical reads..
can anyone help me out of this
thanks
ajuHi,
Can you please format your explain plan using
{ code } --without space
Explain plan
{ code } -- without any space
What is your DB version?
There are differences in access and filter criteria...
-- FRIST QUERY
5 - access("A"."CREATEDBY"="J"."EMPIID"(+))
6 - access("A"."TERMSIID"="H"."PAYMENTTERMSIID")
7 - access("D"."CUSTOMERIID"="F"."CUSTOMERIID")
12 - access("B"."SITEIID"=300964)
14 - access("B"."PARENTIID"="I"."GROUPIID"(+))
15 - filter("A"."TYPE"=4 AND "A"."INVOICEID" LIKE '%')
16 - access("A"."SITEIID"=300964)
18 - access("A"."BILLINGCUSTOMERIID"="D"."CUSTOMERIID")
23 - access(ROWID=ROWID)
27 - access(ROWID=ROWID)
31 - access("F"."CONTACTIID"="G"."CONTACTIID")
32 - access("E"."ADDRESSIID"=NVL("D"."BILLINGADDRESSIID","D"."ADDRESSIID"))
------SECOND QUERY
1 - filter("G"."CONTACTIID"=MAX("CONTACTIID"))
13 - access("B"."SITEIID"=300964)
15 - access("B"."PARENTIID"="I"."GROUPIID"(+))
16 - filter("A"."TYPE"=4 AND "A"."INVOICEID" LIKE '%%%')
17 - access("A"."SITEIID"=300964)
19 - access("A"."TERMSIID"="H"."PAYMENTTERMSIID")
21 - access("A"."CREATEDBY"="J"."EMPIID"(+))
23 - access("A"."BILLINGCUSTOMERIID"="D"."CUSTOMERIID")
25 - access("D"."CUSTOMERIID"="CUSTOMERIID")
filter("CUSTOMERIID" IS NOT NULL)
26 - access("E"."ADDRESSIID"=NVL("D"."BILLINGADDRESSIID","D"."ADDRESSIID"))-Avinash -
I 'm running the same query against two databases on two different servers, and not seeing the expected results.
Query runs in 6 seconds on server A, and 32 seconds on server B. The database on B is a copy of the database on A, same blocksize, same db_file_multiblock_read_count.
Query is:
SELECT
IMS_BO_PMAN08.REF_ID,( sum(IMS_BO_PMAN08_TRAN.MONTH_13_APR) ) + ( sum(IMS_BO_PMAN08_TRAN.MONTH_14_MAY) ) ,
decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast'),
decode(IMS_BO_PMAN08_TRAN.TRANS_TYPE,'E','Expenditure','U','Unit completions','A','Allocation Takeup','S','SOS units','T','SOS Expenditure','G','Grant Claim Units','H','Larger Homes','C','FC Unit Completions','F','FC Expenditure','V','ACQ Expenditure')
FROM
IMS_BO_PMAN08,
IMS_BO_PMAN08_TRAN
WHERE
( IMS_BO_PMAN08.PROG_MAN_ID=IMS_BO_PMAN08_TRAN.PROG_MAN_ID )
AND ( IMS_BO_PMAN08.VERSION_ID IN (select version_id from ims_bo_version where version_id = 1 ) )
AND ( IMS_BO_PMAN08.INV_REGION_CODE > 2 )
and decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast') ='Actual'
GROUP BY
IMS_BO_PMAN08.REF_ID,decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast'),
decode(IMS_BO_PMAN08_TRAN.TRANS_TYPE,'E','Expenditure','U','Unit completions','A','Allocation Takeup','S','SOS units','T','SOS Expenditure','G','Grant Claim Units','H','Larger Homes','C','FC Unit Completions','F','FC Expenditure','V','ACQ Expenditure');
I am seeing the same execution plan when running the query against either database, with the same cost in each case. However, the physical reads on server B is ten times that of on server A
Server A
=====
293851 rows selected.
Elapsed: 00:00:06.58
Execution Plan
0 SELECT STATEMENT Optimizer=FIRST_ROWS (Cost=50270 Card=27811 Bytes=973385)
1 0 SORT (GROUP BY) (Cost=50270 Card=27811 Bytes=973385)
2 1 HASH JOIN (Cost=50088 Card=27811 Bytes=973385)
3 2 TABLE ACCESS (BY INDEX ROWID) OF 'IMS_BO_PMAN08' (Cost=17990 Card=26243 Bytes=446131)
4 3 INDEX (RANGE SCAN) OF 'IMS_BO_PMAN08_IX1' (UNIQUE) (Cost=105 Card=26243)
5 2 NESTED LOOPS (Cost=32049 Card=107258 Bytes=1930644)
6 5 INDEX (UNIQUE SCAN) OF 'IMS_BO_VERSION_IX1' (UNIQUE)
7 5 TABLE ACCESS (FULL) OF 'IMS_BO_PMAN08_TRAN' (Cost=32048 Card=107258 Bytes=1716128)
Statistics
0 recursive calls
13 db block gets
288529 consistent gets
*18,218 physical reads*
0 redo size
17924295 bytes sent via SQL*Net to client
2174914 bytes received via SQL*Net from client
19592 SQL*Net roundtrips to/from client
0 sorts (memory)
1 sorts (disk)
293851 rows processed
Server B
=====
292677 rows selected.
Elapsed: 00:00:32.66
Execution Plan
0 SELECT STATEMENT Optimizer=FIRST_ROWS (Cost=50255 Card=27805 Bytes=973175)
1 0 SORT (GROUP BY) (Cost=50255 Card=27805 Bytes=973175)
2 1 HASH JOIN (Cost=50073 Card=27805 Bytes=973175)
3 2 TABLE ACCESS (BY INDEX ROWID) OF 'IMS_BO_PMAN08' (Cost=17984 Card=26237 Bytes=446029)
4 3 INDEX (RANGE SCAN) OF 'IMS_BO_PMAN08_IX1' (UNIQUE) (Cost=105 Card=26237)
5 2 NESTED LOOPS (Cost=32040 Card=107230 Bytes=1930140)
6 5 INDEX (UNIQUE SCAN) OF 'IMS_BO_VERSION_IX1' (UNIQUE)
7 5 TABLE ACCESS (FULL) OF 'IMS_BO_PMAN08_TRAN' (Cost=32039 Card=107230 Bytes=1715680)
Statistics
0 recursive calls
357 db block gets
250918 consistent gets
*188,332 physical reads*
0 redo size
17853447 bytes sent via SQL*Net to client
2166145 bytes received via SQL*Net from client
19513 SQL*Net roundtrips to/from client
0 sorts (memory)
1 sorts (disk)
292677 rows processed
8.1.6.3 on solaris 8
Can anyone tell me where the excessive physical i/o's (and presumably associated runtime) is coming from? Any pointers much appreciated.
Pete
Edited by: user12248598 on 17-Mar-2010 09:01sort_area_size, sort_area_retained_size & hash_area_size are the same size for both instances, as are all NLS settings.
Tables are not specified NOCACHE, and there are no additional buffer pools.
Running with sql_trace enabled for both queries highlighed some very interesting results:
For the slow query, this is the tkprof output, unfortunately waits=yes is not available in 8.1.6
TKPROF: Release 8.1.6.3.0 - Production on Tue Mar 23 14:54:18 2010
(c) Copyright 1999 Oracle Corporation. All rights reserved.
Trace file: imsroc_ora_10166.trc
Sort options: default
count = number of times OCI procedure was executed
cpu = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk = number of physical reads of buffers from disk
query = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows = number of rows processed by the fetch or execute call
alter session set events '10046 trace name context forever, level 8'
call count cpu elapsed disk query current rows
Parse 0 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 1 0.00 0.00 0 0 0 0
Misses in library cache during parse: 0
Misses in library cache during execute: 1
Optimizer goal: FIRST_ROWS
Parsing user id: 5
BEGIN DBMS_APPLICATION_INFO.SET_MODULE(:1,NULL); END;
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.01 0.01 0 0 0 1
Fetch 0 0.00 0.00 0 0 0 0
total 2 0.01 0.01 0 0 0 1
Misses in library cache during parse: 1
Optimizer goal: FIRST_ROWS
Parsing user id: 5
SELECT
IMS_BO_PMAN08.REF_ID,
( sum(IMS_BO_PMAN08_TRAN.MONTH_13_APR) ) + ( sum(IMS_BO_PMAN08_TRAN.MONTH_14_MAY) ) ,
decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast'),
decode(IMS_BO_PMAN08_TRAN.TRANS_TYPE,'E','Expenditure','U','Unit completions','A','Allocation Takeup
','S','SOS units','T','SOS Expenditure','G','Grant Claim Units','H','Larger Homes','C','FC Unit Comple
tions','F','FC Expenditure','V','ACQ Expenditure')
FROM
bo_ims.IMS_BO_PMAN08,
bo_ims.IMS_BO_PMAN08_TRAN
WHERE ( IMS_BO_PMAN08.PROG_MAN_ID=IMS_BO_PMAN08_TRAN.PROG_MAN_ID )
AND ( IMS_BO_PMAN08.VERSION_ID IN (select version_id from bo_ims.ims_bo_version where version_id =
1 ) )
AND ( IMS_BO_PMAN08.INV_REGION_CODE > 2 )
and decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast') = 'Actual'
GROUP BY
IMS_BO_PMAN08.REF_ID,
decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast'),
decode(IMS_BO_PMAN08_TRAN.TRANS_TYPE,'E','Expenditure','U','Unit completions','A','Allocation Takeup
','S','SOS units','T','SOS Expenditure','G','Grant Claim Units','H','Larger Homes','C','FC Unit Comple
tions','F','FC Expenditure','V','ACQ Expenditure')
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 16278 15.36 36.39 215625 251560 361 244156
total 16280 15.36 36.39 215625 251560 361 244156
Misses in library cache during parse: 0
Optimizer goal: FIRST_ROWS
Parsing user id: 5
OVERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS
call count cpu elapsed disk query current rows
Parse 2 0.00 0.00 0 0 0 0
Execute 3 0.01 0.01 0 0 0 1
Fetch 16278 15.36 36.39 215625 251560 361 244156
total 16283 15.37 36.40 215625 251560 361 244157
Misses in library cache during parse: 1
Misses in library cache during execute: 1
OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS
call count cpu elapsed disk query current rows
Parse 0 0.00 0.00 0 0 0 0
Execute 0 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 0 0.00 0.00 0 0 0 0
Misses in library cache during parse: 0
3 user SQL statements in session.
0 internal SQL statements in session.
3 SQL statements in session.
Trace file: imsroc_ora_10166.trc
Trace file compatibility: 8.00.04
Sort options: default
2 sessions in tracefile.
5 user SQL statements in trace file.
0 internal SQL statements in trace file.
3 SQL statements in trace file.
3 unique SQL statements in trace file.
75998 lines in trace file.And this is the tkprof formatted output for the faster running query:
TKPROF: Release 8.1.6.3.0 - Production on Tue Mar 23 14:56:28 2010
(c) Copyright 1999 Oracle Corporation. All rights reserved.
Trace file: imslive_ora_7489.trc
Sort options: default
count = number of times OCI procedure was executed
cpu = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk = number of physical reads of buffers from disk
query = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows = number of rows processed by the fetch or execute call
alter session set events '10046 trace name context forever, level 8'
call count cpu elapsed disk query current rows
Parse 0 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 1 0.00 0.00 0 0 0 0
Misses in library cache during parse: 0
Misses in library cache during execute: 1
Optimizer goal: FIRST_ROWS
Parsing user id: 5
SELECT
IMS_BO_PMAN08.REF_ID,
( sum(IMS_BO_PMAN08_TRAN.MONTH_13_APR) ) + ( sum(IMS_BO_PMAN08_TRAN.MONTH_14_MAY) ) ,
decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,:SYS_B_00,:SYS_B_01,:SYS_B_02,:SYS_B_03),
decode(IMS_BO_PMAN08_TRAN.TRANS_TYPE,:SYS_B_04,:SYS_B_05,:SYS_B_06,:SYS_B_07,:SYS_B_08,:SYS_B_09,:SYS_B_10,:
SYS_B_11,:SYS_B_12,:SYS_B_13,:SYS_B_14,:SYS_B_15,:SYS_B_16,:SYS_B_17,:SYS_B_18,:SYS_B_19,:SYS_B_20,:SYS_B_21,:
SYS_B_22,:SYS_B_23)
FROM
BO_IMS.IMS_BO_PMAN08,
BO_IMS.IMS_BO_PMAN08_TRAN
WHERE ( IMS_BO_PMAN08.PROG_MAN_ID=IMS_BO_PMAN08_TRAN.PROG_MAN_ID )
AND ( IMS_BO_PMAN08.VERSION_ID IN (select version_id from bo_ims.ims_bo_version where version_id = :SYS_B_
24 ) )
AND ( IMS_BO_PMAN08.INV_REGION_CODE > :SYS_B_25 )
and decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,:SYS_B_26,:SYS_B_27,:SYS_B_28,:SYS_B_29) = :SYS_B_30
GROUP BY
IMS_BO_PMAN08.REF_ID,
decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,:SYS_B_31,:SYS_B_32,:SYS_B_33,:SYS_B_34),
decode(IMS_BO_PMAN08_TRAN.TRANS_TYPE,:SYS_B_35,:SYS_B_36,:SYS_B_37,:SYS_B_38,:SYS_B_39,:SYS_B_40,:SYS_B_41,:
SYS_B_42,:SYS_B_43,:SYS_B_44,:SYS_B_45,:SYS_B_46,:SYS_B_47,:SYS_B_48,:SYS_B_49,:SYS_B_50,:SYS_B_51,:SYS_B_52,:
SYS_B_53,:SYS_B_54)
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 2 0.00 0.00 0 0 0 0
Fetch 20042 0.00 0.00 20064 295221 13 300608
total 20045 0.00 0.00 20064 295221 13 300608
Misses in library cache during parse: 1
Optimizer goal: FIRST_ROWS
Parsing user id: 5
Rows Row Source Operation
300608 SORT GROUP BY
300628 NESTED LOOPS
55647 NESTED LOOPS
2 INDEX UNIQUE SCAN (object id 151050)
55647 TABLE ACCESS BY INDEX ROWID IMS_BO_PMAN08
55649 INDEX RANGE SCAN (object id 185149)
300628 TABLE ACCESS BY INDEX ROWID IMS_BO_PMAN08_TRAN
356274 INDEX RANGE SCAN (object id 157241)
DELETE FROM PLAN_TABLE
WHERE
STATEMENT_ID=:1
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 3 5 12 0
Fetch 0 0.00 0.00 0 0 0 0
total 2 0.00 0.00 3 5 12 0
Misses in library cache during parse: 1
Optimizer goal: FIRST_ROWS
Parsing user id: 5
Rows Row Source Operation
1 DELETE PLAN_TABLE
1 TABLE ACCESS FULL PLAN_TABLE
EXPLAIN PLAN SET STATEMENT_ID='PLUS18028884' FOR SELECT
IMS_BO_PMAN08.REF_ID,
( sum(IMS_BO_PMAN08_TRAN.MONTH_13_APR) ) + ( sum(IMS_BO_PMAN08_TRAN.MONTH_14_MAY) ) ,
decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast'),
decode(IMS_BO_PMAN08_TRAN.TRANS_TYPE,'E','Expenditure','U','Unit completions','A','Allocation Takeup','S','S
OS units','T','SOS Expenditure','G','Grant Claim Units','H','Larger Homes','C','FC Unit Completions','F','FC E
xpenditure','V','ACQ Expenditure')
FROM
BO_IMS.IMS_BO_PMAN08,
BO_IMS.IMS_BO_PMAN08_TRAN
WHERE ( IMS_BO_PMAN08.PROG_MAN_ID=IMS_BO_PMAN08_TRAN.PROG_MAN_ID )
AND ( IMS_BO_PMAN08.VERSION_ID IN (select version_id from bo_ims.ims_bo_version where version_id = 1 ) )
AND ( IMS_BO_PMAN08.INV_REGION_CODE > 2 )
and decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast') = 'Actual'
GROUP BY
IMS_BO_PMAN08.REF_ID,
decode(IMS_BO_PMAN08_TRAN.TRANS_SUB_TYPE,'A','Actual','F','Forecast'),
decode(IMS_BO_PMAN08_TRAN.TRANS_TYPE,'E','Expenditure','U','Unit completions','A','Allocation Takeup','S','S
OS units','T','SOS Expenditure','G','Grant Claim Units','H','Larger Homes','C','FC Unit Completions','F','FC E
xpenditure','V','ACQ Expenditure')
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 0 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 1 0.00 0.00 0 0 0 0
Misses in library cache during parse: 1
Optimizer goal: FIRST_ROWS
Parsing user id: 5
insert into plan_table (statement_id, timestamp, operation, options,
object_node, object_owner, object_name, object_instance, object_type,
search_columns, id, parent_id, position, other,optimizer, cost, cardinality,
bytes, other_tag, partition_start, partition_stop, partition_id,
distribution )
values
(:1,SYSDATE,:2,:3,:4,:5,:6,:7,:8,:9,:10,:11,:12,:13,:14,:15,:16,:17,:18,:19,
:20,:21,:22)
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 7 0.00 0.00 1 3 9 7
Fetch 0 0.00 0.00 0 0 0 0
total 8 0.00 0.00 1 3 9 7
Misses in library cache during parse: 1
Optimizer goal: FIRST_ROWS
Parsing user id: 5 (recursive depth: 1)
select o.name, u.name
from
sys.obj$ o, sys.user$ u where obj# = :1and owner# = user#
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 2 0.00 0.00 0 0 0 0
Fetch 2 0.00 0.00 3 12 0 2
total 5 0.00 0.00 3 12 0 2
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: SYS (recursive depth: 1)
OVERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS
call count cpu elapsed disk query current rows
Parse 3 0.00 0.00 0 0 0 0
Execute 4 0.00 0.00 3 5 12 0
Fetch 20042 0.00 0.00 20064 295221 13 300608
total 20049 0.00 0.00 20067 295226 25 300608
Misses in library cache during parse: 3
Misses in library cache during execute: 1
OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS
call count cpu elapsed disk query current rows
Parse 2 0.00 0.00 0 0 0 0
Execute 9 0.00 0.00 1 3 9 7
Fetch 2 0.00 0.00 3 12 0 2
total 13 0.00 0.00 4 15 9 9
Misses in library cache during parse: 2
5 user SQL statements in session.
1 internal SQL statements in session.
6 SQL statements in session.
Trace file: imslive_ora_7489.trc
Trace file compatibility: 8.00.04
Sort options: default
3 sessions in tracefile.
8 user SQL statements in trace file.
1 internal SQL statements in trace file.
6 SQL statements in trace file.
6 unique SQL statements in trace file.
77410 lines in trace file.The sql statement as run did not make use of bind variables, so the ones in the tkprof output for the longer running statement made me immediately think of cursor sharing, and right there in the init.ora for the faster running database was CURSOR_SHARING=FORCE.
I'm not familiar with the history of the databases, nor the specific reasoning for enabling cursor sharing (bind variable usage seems prevalent in all custom code) so I've replicated the setting on the slower database, resulting in a similar tkprof output to the faster server, with a runtime of 7 seconds for 2nd and subsequent runs.
My immediate issue is now solved, thanks to all who contributed, and apologies for not spotting the obvious earlier.
Regards, Pete -
High user input output (I/O) and physical reads
Hi guys
Recently we have noticed that our database performance degraded significantly. as we looked around in grid control we noticed that the user IO and Physical reads are really high which cause the database to be laggy.
at first we thought it was memory problem, so we added 2gb to sga. we have set sga to be automatic and it's been like this for the past 2 years.
how do i trouble shoot this problem. i haven't found any troubleshooting guide for it yet.
please instruct me on how to solve it
database: 10.2.0.4 sparc
regards
SinaTop 5 Timed events
db file sequential read 23,582 679 29 46.3 User I/O
CPU time 626 42.7
db file scattered read 3,089 70 23 4.8 User I/O
db file parallel write 3,478 28 8 1.9 System I/O
log file parallel write 4,201 24 6 1.7 System I/O
SGA Memory Summary
SGA regions Begin Size (Bytes) End Size (Bytes) (if different)
Database Buffers 2,768,240,640 2,835,349,504
Fixed Size 2,050,240
Redo Buffers 14,721,024
Variable Size 3,657,439,040 3,590,330,176
Process Memory Summary
Category Alloc (MB) Used (MB) Avg Alloc (MB) Std Dev Alloc (MB) Max Alloc (MB) Hist Max Alloc (MB) Num Proc Num Alloc
B Other 569.22 0 2.62 3.14 22 24 217 217
Freeable 101.63 0.00 0.77 0.45 3 132 132
SQL 91.51 45.35 0.44 0.76 4 78 209 192
PL/SQL 12.50 5.57 0.06 0.07 0 4 217 217
JAVA 5.40 5.38 1.08 0.09 1 2 5 5
E Other 603.20 3.03 3.62 22 24 199 199
SQL 115.21 64.78 0.60 1.67 21 78 191 182
Freeable 112.31 0.00 0.83 0.43 3 135 135
PL/SQL 13.89 5.94 0.07 0.12 1 4 199 199
JAVA 8.93 8.89 1.12 0.23 2 2
for some reason i can't paste a table into this post but if you want i can email you above tables -
Unable to reduce Physical Reads
Hi
Problem:
Need to reduce the Physical reads in Oracle 8.1.7
Information:
Optimizer_mode= Choose
Statistics will not be gathered.
Intially the cache hit ratio is 18%. At this point when we checked the SQL Statement
SELECT a32,
F_DOCNUMBER,NVL(a109,'BIWS') AS WorkFlow,
a147 AS Service_Subsidary,
a89 AS StaffInd,
a88 AS SubsidiaryInd
FROM doctaba
WHERE a94 = 'CCOC_CARDS_CCA_060824_6'
AND a40 IN ('3','4','5')
0 recursive calls
81 db block gets
5020 consistent gets
3909 physical reads
0 redo size
401 bytes sent via SQL*Net to client
311 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed.
Once we increase the Buffer Cache Hit Ratio to 90% We got the following
0 recursive calls
81 db block gets
3717 consistent gets
3576 physical reads
0 redo size
401 bytes sent via SQL*Net to client
311 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed.
But can you please advice how to reduce the Physical Reads further.
Note: Table DOCTABA is a Snapshot that is present in Other Database.
Please advice!!
Cheers
Ramkannan.ABuffer hit cache ratios are totally meaningless as was proven many years ago by Connor's brilliant little utility that allows you to dial in any ratio you want.
The reason your are getting FTEs is because your totally antiquated version of the product, never supported during the current century, is that it thinks FTEs cost less than using any indexes that may (or may not) exist. You've not established in your email that there are any indexes or posted DDL or provided much of anything else that would be helpful.
I would think moving from the Jurassic to 10.2.0.4, or above, would be your first priority. -
Consistent gets/physical reads issue
Dear all,
There are not any of DML on table tb_hxl_user.
First Select:
SQL> select count(1) from tb_hxl_user;
COUNT(1)
286435658
Elapsed: 00:04:03.67
Statistics
357 recursive calls
0 db block gets
2106478 consistent gets
2106316 physical reads
0 redo size
422 bytes sent via SQL*Net to client
416 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
6 sorts (memory)
0 sorts (disk)
1 rows processed Second Select:
SQL> select count(1) from tb_hxl_user;
COUNT(1)
286435658
Elapsed: 00:03:02.29
Statistics
0 recursive calls
0 db block gets
2106395 consistent gets
2106273 physical reads
0 redo size
422 bytes sent via SQL*Net to client
416 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed After the first,I know that all the blocks have been flushed to SGA,
but the second select,it generated many " 2106395 consistent gets" and " 2106273 physical reads" also,
why?What exactly is consistent gets read below link:
http://jonathanlewis.wordpress.com/2009/06/12/consistent-gets-2/
Which is similar to docs clearity and authenticity.
What exactly is physical read read below link:
http://download.oracle.com/docs/cd/B16240_01/doc/doc.102/e16282/oracle_database_help/oracle_database_instance_throughput_physreads_ps.html
Regards
Girish Sharma
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