High Latch Free Contention (RequestsResult Cache: RC Latch) Due to High Hard Parses
(Doc ID 2375660.1)
Last updated on FEBRUARY 21, 2024
Applies to:
Oracle Database - Enterprise Edition - Version 12.1.0.2 and laterOracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.
Symptoms
- High latch free waits with high parse count:
From problem awr report
Event Waits Total Wait Time (sec) Wait Avg(ms) % DB time Wait Class
latch free 478,125 59.4K 124.25 77.6 Other <<<<###### high latch free contention
DB CPU 9,909.4 12.9latch causing the problem
Latch Name Get Requests Pct Get Miss Avg Slps /Miss Wait Time (s)
RequestsResult Cache: RC Latch 696,568 70.13 1.01 59409parse count (hard) 437,748 122.85 361.48 <<<<<<<########### VERY HIGH HARD PARSE COUNT
parse count (total) 928,306 260.51 766.56execute count 1,326,417 <<<< executions per hour
due to all the hard parses
high rate of dynamic sqlnumber of executions
6,069 f5snajx72 SELECT /* DS_SVC */ /*+ dynami...
5,646 8u0qcsrjx SELECT /* DS_SVC */ /*+ dynami...
6,070 a6p6fb7uf SELECT /* DS_SVC */ /*+ dynami...
5,648 2vuxj27q SELECT /* DS_SVC */ /*+ dynami...
4,363 df89awm SELECT /* DS_SVC */ /*+ dynami...
4,066 6w3h49xy SELECT /* DS_SVC */ /*+ dynami...
4,056 16f9szag4 SELECT /* DS_SVC */ /*+ dynami...
Cause
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In this Document
Symptoms |
Cause |
Solution |