Streams Apply Servers Consume Excessive PGA Memory when Using a Statement DML Handler (Doc ID 1527049.1)

Last updated on AUGUST 12, 2014

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.1 to 11.2.0.3 [Release 11.2]
Information in this document applies to any platform.

Symptoms

The PGA memory consumption of the Apply server processes is excessive when using a statement DML Handler which is utilzing :lcr.KEEP_COLUMNS.

This memory consumption affects the throughput of the system. When the Apply is stopped and restarted the throughput of the system returns to an acceptable level.

The Apply server processes spend a lot of time allocating memory as per the
following stack

kghprmalo()
<-kghalp()
<-knllcnamealloc()
<-kgghstcrt()
<-knllr_prep_kcols()
<-knalh_lme_keep_columns()
<-knalh_execute_lme()

Leading to the following accumulation of freeable PGA memory associated with
kol vstring

Cause

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