Slow Performance with High 'latch free' on 'ges value block free list' (Doc ID 1664425.1)

Last updated on OCTOBER 13, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.3 and later
Information in this document applies to any platform.

Symptoms

The database performance is slow with high "latch free" waits on "ges value block free list", per AWR report:

Top 5 Timed Foreground Events

Event                   Waits   Time(s) Avg wait (ms)  % DB time Wait Class
latch free              34,061  17,374         510     54.59      Other    <===       
resmgr:cpu quantum     252,146   5,743          23     18.04      Scheduler
latch: shared pool      16,118   2,226         138      6.99      Concurrency
rdbms ipc reply        134,092   1,576          12      4.95      Other
DB CPU                           1,283                  4.03

Latch Name                  Get Requests   Pct Get     Miss  Avg Slps /Miss Wait Time (s) NoWait Requests Pct NoWait Miss
ges caches resource lists      505,253        0.26      0.78           221                   267,069             0.49
ges resource hash list       9,817,950        0.21      0.10           337                   122,156             0.35
ges resource scan list           5,235        0.00         0             0
ges resource table freelist    213,866        0.03      0.62             7                         0
ges timeout list                89,602        0.04      0.06             0                     7,828             0.01
ges value block free list    2,729,070        1.79      0.65         16134                         0           <====

Latch Miss Sources

Latch Name                        Where             NoWait Misses Sleeps Waiter Sleeps
ges value block free list   kjvblkfr: free              0         18,209     10,641     <====
ges value block free list   kjvblkgrow: allocation      0         12,772     20,339     <====



The application is doing a lot of distributed transactions via dblink. lmd trace file shows heavy DX lock requests:

grep DX racprod1_lmd0_2320.trc
----------------------
resname       : [0x7ec6c466][0x0],[DX][ext 0x0,0x0]
resname       : [0x7ec6c466][0x0],[DX][ext 0x0,0x0]
resname       : [0x883aba56][0x0],[DX][ext 0x0,0x0]
resname       : [0x883aba56][0x0],[DX][ext 0x0,0x0]
resname       : [0x9cc8d348][0x0],[DX][ext 0x0,0x0]
resname       : [0x9cc8d348][0x0],[DX][ext 0x0,0x0]
resname       : [0xf9e8a07e][0x0],[DX][ext 0x0,0x0]
resname       : [0xf9e8a07e][0x0],[DX][ext 0x0,0x0]
resname       : [0x75f90a52][0x0],[DX][ext 0x0,0x0]
resname       : [0x75f90a52][0x0],[DX][ext 0x0,0x0]
....

 

Cause

Sign In with your My Oracle Support account

Don't have a My Oracle Support account? Click to get started

My Oracle Support provides customers with access to over a
Million Knowledge Articles and hundreds of Community platforms