This occurs when the number of tasks created in the Altibase server reaches MAX_CLIENT.
The task Task is an object created when a new connection is made to the Altibase server. The maximum number of simultaneous creations is affected by the value of the Altibase server property MAX_CLIENT.
$ is -silent [ERR-91015 : Communication failure.]
TRANSACTION_TABLE_SIZE is full !! Current TRANSACTION_TABLE_SIZE is 1024 Please check TRANSACTION_TABLE_SIZE
How to check
To find the cause of the task pool overflow, the following items must be checked.
- MAX_CLIENT property setting value
- Number of sessions connected to Altibase server
If the number of sessions connected to the Altibase server is equal to MAX_CLIENT, it is caused by increased sessions. If it is less than MAX_CLIENT, check the number of tasks.
- Number of tasks created in Altibase server
If the number of sessions is less than MAX_CLIENT and the number of tasks is equal to or greater than MAX_CLIENT, you can suspect the cause below.
When all service threads are in EXECUTE state and a new connection occurs and the task is increased.
When the number of transactions reaches TRANSACTION_TABLE_SIZE and a new connection occurs and the task increases
If the number of transactions exceeds TRANSACTION_TABLE_SIZE, the message TRANSACTION_TABLE_SIZE is full is left.
How to check MAX_CLIENT setting value
Task pool overflow occurs when the number of tasks exceeds the value of the MAX_CLIENT property, so check the value of this property first.
When iSQL connection is possible
Code Block language sql
iSQL> set linesize 1024; iSQL> set colsize 30; iSQL> SELECT NAME, VALUE1 FROM V$PROPERTY WHERE NAME = 'MAX_CLIENT'; NAME VALUE1 ------------------------------------------------------------------- MAX_CLIENT 1000 1 row selected
When iSQL connection is not possible
Code Block language bash
$ grep MAX_CLIENT $ALTIBASE_HOME/conf/altibase.properties
How to check the number of sessions
- When iSQL connection is possible
If iSQL access is available, the number of sessions can be checked with the performance view, and through this, you can infer the cause of task pool overflow to some extent.
If the current number of sessions is compared with the MAX_CLIENT value, and the value is the same, the increase in sessions is the cause.
If the current number of sessions is less than MAX_CLIENT, it could be due to two other things than the session growth.
Code Block title How to check the number of sessions language sql
$ export ISQL_CONNECTION = IPC $ is -silent -sysdba iSQL> SELECT COUNT(*) FROM V$SESSION; -- Check the current number of sessions COUNT ----------------------- 1000 1 row selected.
- When iSQL connection is not possible
If it is difficult to connect to iSQL, the number of sessions must be checked with the information on the OS.
Depending on the client's connection method, there are two ways to check it.
In the case of connecting using both TCP and IPC methods, the user can add up the results and compare them with MAX_CLIENT to determine whether the increase in sessions or other parts are the causes.
Code Block title When the client connects with TCP language bash
$ netstat -an | grep 20300 | grep ESTA | wc -l # Compare the result to MAX_CLIENT Or $ lsof -p pid # Compare the number of socket files open by the Altibase server with MAX_CLIENT.
Code Block title When the client connects with IPC language bash
# Linux $ ipcs -m | grep -i -e nattch -e eheejung key shmid owner perms bytes nattch status 0x00003ed0 458761 altibase 666 131104 1 # HP-UX, AIX $ ipcs -ma | grep -e NATTCH -e eheejung T ID KEY MODE OWNER GROUP CREATOR CGROUP NATTCH SEGSZ CPID LPID ATIME DTIME CTIME m 7438362 0x00003353 --rw-rw-rw- altibase users altibase users 1 655480 13139 12411 17:57:48 no-entry 10:22:18 # SunOS $ ipcs -ma | /usr/xpg4/bin/grep -e NATTCH -e beadskin T ID KEY MODE OWNER GROUP CREATOR CGROUP NATTCH SEGSZ CPID LPID ATIME DTIME CTIME m 9 0x3863 --rw-rw-rw- altibase other altibase other 1 983576 14435 14435 17:31:35 no-entry 17:31:35
How to check the number of tasks
- When iSQL connection is possible
If the number of sessions is less than MAX_CLIENT, other causes should be investigated.
Check the number of tasks with the command below and compare the number of tasks with MAX_CLIENT. The value of logon current means the number of tasks created and can be greater than the number of sessions.
iSQL> SELECT NAME, VALUE FROM V$SYSSTAT WHERE NAME = 'logon current';
If the number of sessions is less than MAX_CLIENT and the value of logon current is equal to or greater than MAX_CLIENT, there are two possible causes:
-When all service threads are in EXECUTE state and a new connection occurs and the task increases
-When a new connection occurs while the number of transactions reaches TRANSACTION_TABLE_SIZE and the task increases
- When iSQL connection is not possible
The number of created tasks can be checked by the logon current value of v$sysstat. However, if a task pool overflow occurs, you may not be able to execute the above statement because a new connection cannot be established.
In this case, the number of tasks must be checked with the number of open files in the Altibase server process with the lsof command.
Code Block title Example of executing lsof in Linux language bash
$ lsof -p PID | grep -e IPv4 -e sock | grep -v LISTEN altibase 7494 eheejung 38u IPv4 40725257 TCP localhost:21109->localhost:36248 (ESTABLISHED) # Sessions in which the connection was established normally, included in the task. altibase 7494 eheejung 39u IPv4 40725262 TCP localhost:21109->localhost:36249 (ESTABLISHED) altibase 7494 eheejung 40u sock 0,4 40726084 can't identify protocol # All service threads are in EXECUTE state or altibase 7494 eheejung 41u sock 0,4 40726576 can't identify protocol # When connection fails due to exceeding TRANSACTION_TABLE_SIZE altibase 7494 eheejung 42u sock 0,4 40726604 can't identify protocol # Remaining task
On Solaris, the pfiles command can be used instead of lsof.
$ pfiles PID | grep sock sockname: AF_INET 0.0.0.0 port: 21109 # LISTEN sockname: AF_INET 127.0.0.1 port: 21109 # A session in which the connection was established normally, and this is also included in the task. sockname: AF_INET 127.0.0.1 port: 21109 sockname: AF_INET 127.0.0.1 port: 21109 sockname: AF_INET 127.0.0.1 port: 21109 sockname: AF_INET 0.0.0.0 port: 0 # If all service threads are in EXECUTE state or the connection fails due to exceeding TRANSACTION_TABLE_SIZE, the remaining tasks. sockname: AF_INET 0.0.0.0 port: 0 sockname: AF_INET 0.0.0.0 port: 0
Change MAX_CLIENT property
If there are many actual simultaneous connection sessions, you need to change MAX_CLIENT.
When the number of simultaneous connection sessions increases, the number of concurrent transactions increases, and in the case of Unix/Linux systems, the number of open files increases.
Therefore, if you change MAX_CLIENT larger than the existing value, the following values must be changed as well.
- max open files
If the application has the following characteristics, it is necessary to check the necessity again.
Unless the above processing is inevitable due to the nature of the service, consider changing the session to end immediately after the transaction is completed.
If keep making new connections
Maintaining unnecessarily connected sessions even though they no longer need to be connected