Whether the maximum number of connections is set in Oracle or an error is returned

Whether the maximum number of connections is set in Oracle or an error is returned

There are 1100 data records to be updated, and an error is reported during connection.

ORA-12518, TNS: listener cocould not hand off client connection

According to the article of the product, the maximum number of connections is set to 1200, and the session is 1200*1.1 + 5 = 1325. However, tomcat still reports an error.

ORA-12518, TNS: listener cocould not hand off client connection

View the maximum number of connections:

SQL> show parameter processes;
NAME TYPE VALUE
-----------------------------------------------------------------------------
Aq_tm_processes integer 0
Db_writer_processes integer 1
Gcs_server_processes integer 0
Job_queue_processes integer 10
Log_archive_max_processes integer 2

Processes integer 1200

View the current database v $ processes only 356, v $ session 352

PMON updates the content in the listener every five minutes, so the listener and the database are not necessarily synchronized. You now know from the database that there are 356 connections, does not mean that the listener records 356, within 5 minutes it is likely that pmon has not been updated, still 1200 so you report ORA-12518 rather than ora-00020

SQL> show parameter pga;
 
NAME TYPE VALUE
-----------------------------------------------------------------------------
Pga_aggregate_target big integer 194 M
 
SQL> select * from v $ resource_limit;
 
RESOURCE_NAME CURRENT_UTILIZATION MAX_UTILIZATION INITIAL_ALLOCATION LIMIT_VALUE
--------------------------------------------------------------------------------------------------------
Processes 24 366 1200 1200
Sessions 27 362 1325 1325
Enqueue_locks 15 25 15950 15950
Enqueue_resources 15 43 6048 UNLIMITED
Ges_procs 0 0 0 0
Ges_ress 0 0 0 UNLIMITED
Ges_locks 0 0 0 UNLIMITED
Ges_cache_ress 0 0 0 UNLIMITED
Ges_reg_msgs 0 0 0 UNLIMITED
Ges_big_msgs 0 0 0 UNLIMITED
Ges_rsv_msgs 0 0 0 0
Gcs_resources 0 0 0 0
Gcs_shadows 0 0 0 0
Dml_locks 0 51 5828 UNLIMITED
Temporary_table_locks 0 3 UNLIMITED
Transactions 1 7 1457 UNLIMITED
Branches 0 0 1457 UNLIMITED
Cmtcallbk 0 2 1457 UNLIMITED
Sort_segment_locks 0 3 UNLIMITED
Max_rollback_segments 11 11 1457 65535
 
RESOURCE_NAME CURRENT_UTILIZATION MAX_UTILIZATION INITIAL_ALLOCATION LIMIT_VALUE
--------------------------------------------------------------------------------------------------------
Max_shared_servers 1 1 UNLIMITED
Parallel_max_servers 0 0 40 3600
 
22 rows selected

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