Expdp Is Very Slow After Upgrade From 11.2.0.3 To 11.2.0.4 With Wait On AQ: enqueue blocked on low memory (Doc ID 1990633.1)

Last updated on OCTOBER 31, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.4 to 11.2.0.4 [Release 11.2]
Information in this document applies to any platform.

Symptoms

Expdp is extremely slow after upgrading from 11.2.0.3 to 11.2.0.4. Compared to 11.2.0.3, expdp performs badly when exporting empty partitions or subpartitions.

The 10046 trace shows the problem is waiting for 'Streams AQ: enqueue blocked on low memory' as shown below:

OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS

call     count       cpu    elapsed       disk      query    current        rows
------- ------  -------- ---------- ---------- ---------- ----------  ----------
Parse    12990      0.43       0.73          0         12        100           0
Execute  37965     25.93    8216.31       5760    1913414      91738       25885
Fetch    23310      4.28       7.23         10     974763          0       28614
------- ------  -------- ---------- ---------- ---------- ----------  ----------
total    74265     30.65    8224.28       5770    2888189      91838       54499

Misses in library cache during parse: 367
Misses in library cache during execute: 181

Elapsed times include waiting on following events:
 Event waited on                             Times   Max. Wait  Total Waited
 ----------------------------------------   Waited  ----------  ------------
 KSV master wait                                 1        0.00          0.00
 Disk file operations I/O                      101        0.00          0.00
 Streams AQ: enqueue blocked on low memory
                                              4928       59.91       8147.57
 wait for unread message on broadcast channel
                                                27        1.00         20.21
 db file sequential read                       886        0.02          0.77

...

 

Changes

 Upgrade from 11.2.0.3 to 11.2.0.4.

Cause

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