Lockers becomes more and more

Question

my application will fork child process periodically ,these processes
will read DBs ,do some analysis and exit , they will close all cursors
,DB, and environment before exits.
I found that db_stat -CA will show more and more lockers as time went
on:
chenyajun@netwise:data$ db_stat -CA
Default locking region information:
5027 Last allocated locker ID
0x7fffffff Current maximum unused locker ID
5 Number of lock modes
20000 Maximum number of locks possible
1000 Maximum number of lockers possible
1000 Maximum number of lock objects possible
0 Number of current locks
30 Maximum number of locks at any one time
68 Number of current lockers
93 Maximum number of lockers at any one time
0 Number of current lock objects
30 Maximum number of lock objects at any one time
362597 Total number of locks requested
362597 Total number of locks released
0 Total number of lock requests failing because DB_LOCK_NOWAIT
was set
1 Total number of locks not immediately available due to
conflicts
0 Number of deadlocks
60M Lock timeout value (60000000)
0 Number of locks that have timed out
0 Transaction timeout value
0 Number of transactions that have timed out
4MB 144KB The size of the lock region
2 The number of region locks that required waiting (0%)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Lock REGINFO information:
Lock Region type
3 Region ID
__db.003 Region name
0xb78da000 Original region address
0xb78da000 Region address
0xb7cfdf40 Region primary address
0 Region maximum allocation
0 Region allocated
REGION_JOIN_OK Region flags
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Lock region parameters:
1031 locker table size
1031 object table size
4333280 obj_off
0 osynch_off
4325024 locker_off
0 lsynch_off
0 need_dd
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Lock conflict matrix:
0 0 0 0 0
0 0 1 0 0
0 1 1 1 1
0 0 0 0 0
0 0 1 0 1
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Locks grouped by lockers:
Locker Mode Count Status ----------------- Object
c75 dd= 0 locks held 0 write locks 0
64 dd=19 locks held 0 write locks 0
c7c dd= 0 locks held 0 write locks 0
6c dd=18 locks held 0 write locks 0
87e dd= 0 locks held 0 write locks 0
c86 dd= 0 locks held 0 write locks 0
885 dd= 0 locks held 0 write locks 0
c8d dd= 0 locks held 0 write locks 0
c97 dd= 0 locks held 0 write locks 0
87 dd=17 locks held 0 write locks 0
c9e dd= 0 locks held 0 write locks 0
8e dd=16 locks held 0 write locks 0
498 dd= 0 locks held 0 write locks 0
ca8 dd= 0 locks held 0 write locks 0
49f dd= 0 locks held 0 write locks 0
caf dd= 0 locks held 0 write locks 0
a2 dd=15 locks held 0 write locks 0
cb9 dd= 0 locks held 0 write locks 0
cc0 dd= 0 locks held 0 write locks 0
10cb dd= 0 locks held 0 write locks 0
af dd=14 locks held 0 write locks 0
cca dd= 0 locks held 0 write locks 0
10d2 dd= 0 locks held 0 write locks 0
cd1 dd= 0 locks held 0 write locks 0
c7 dd=13 locks held 0 write locks 0
d2 dd=12 locks held 0 write locks 0
968 dd= 0 locks held 0 write locks 0
96f dd= 0 locks held 0 write locks 0
979 dd= 0 locks held 0 write locks 0
572 dd= 0 locks held 0 write locks 0
980 dd= 0 locks held 0 write locks 0
579 dd= 0 locks held 0 write locks 0
11a5 dd= 0 locks held 0 write locks 0
11ac dd= 0 locks held 0 write locks 0
1cb dd=11 locks held 0 write locks 0
1d2 dd=10 locks held 0 write locks 0
dfe dd= 0 locks held 0 write locks 0
e05 dd= 0 locks held 0 write locks 0
62d dd= 0 locks held 0 write locks 0
634 dd= 0 locks held 0 write locks 0
63e dd= 0 locks held 0 write locks 0
645 dd= 0 locks held 0 write locks 0
64f dd= 0 locks held 0 write locks 0
656 dd= 0 locks held 0 write locks 0
a71 dd= 0 locks held 0 write locks 0
a78 dd= 0 locks held 0 write locks 0
129f dd= 0 locks held 0 write locks 0
12a6 dd= 0 locks held 0 write locks 0
12b0 dd= 0 locks held 0 write locks 0
296 dd= 9 locks held 0 write locks 0
12b7 dd= 0 locks held 0 write locks 0
12c1 dd= 0 locks held 0 write locks 0
12c8 dd= 0 locks held 0 write locks 0
2ac dd= 8 locks held 0 write locks 0
ed8 dd= 0 locks held 0 write locks 0
edf dd= 0 locks held 0 write locks 0
b4b dd= 0 locks held 0 write locks 0
b52 dd= 0 locks held 0 write locks 0
38f dd= 0 locks held 0 write locks 0
396 dd= 0 locks held 0 write locks 0
7a4 dd= 0 locks held 0 write locks 0
3a0 dd= 0 locks held 0 write locks 0
7ab dd= 0 locks held 0 write locks 0
3a7 dd= 0 locks held 0 write locks 0
fc2 dd= 0 locks held 0 write locks 0
fc9 dd= 0 locks held 0 write locks 0
fd3 dd= 0 locks held 0 write locks 0
fda dd= 0 locks held 0 write locks 0
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Locks grouped by object:
Locker Mode Count Status ----------------- Object
bdb version is 4.3.29
Though the processes closes all the relevent resources(cursor,db,env)
before exit,
why are so many lockers yet?
I use CDB , no txn protected.
init flags for my environment:
DB_CREATE | DB_INIT_MPOOL | DB_INIT_CDB | DB_CDB_ALLDB

Answer 1

Hi,
my application will fork child process periodically
,these processes
will read DBs ,do some analysis and exit , they will
close all cursors
,DB, and environment before exits.
I found that db_stat -CA will show more and more
lockers as time went
on: Is not normal that if you are using the application, lockers number to grow?( this number: 93 Maximum number of lockers at any one time; will continue to grow once the application is running) I'm not sure that your question was very clear.
The maximum number of lockers can be estimated as follows:
- If the database environment is using transactions, the maximum number of lockers can be estimated by adding the number of simultaneously active non-transactional cursors open database handles to the number of simultaneously active transactions and child transactions (where a child transaction is active until it commits or aborts, not until its parent commits or aborts).
- If the database environment is not using transactions, the maximum number of lockers can be estimated by adding the number of simultaneously active non-transactional cursors and open database handles to the number of simultaneous non-cursor operations.
Doc: http://www.oracle.com/technology/documentation/berkeley-db/db/ref/lock/max.html
Regards,
Bogdan Coman, Oracle