Database Was Hung on Row Cache Lock in 12.2 (Doc ID 2631994.1)

Last updated on JULY 20, 2024

Applies to:

Symptoms

• Database hung with blocker 'ROW CACHE LOCK'
• No operation could be performed
• MMON down so unable to generate AWR or ASH report
• Diag tracefile shows following:

  waiting on 'library cache load lock' for 32 seconds, wait id 4
  p1: 'object address'=0x800000043096f5c0, p2: 'lock
  address'=0x800000043959d780, p3: '100*mask+namespace'=0x4f0003
  Blocked by Session ID 1179 serial# 8136 on instance 1
  which is waiting on 'library cache lock' for 764 seconds
  p1: 'handle address'=0x20000004181c7e00, p2: 'lock
  address'=0xd0000004332ba3c0, p3: '100*mode+namespace'=0x1600010002
  Final Blocker is Session ID 482 serial# 2323 on instance 1
  which is waiting on 'row cache lock' for 760 seconds
  p1: 'cache id'=0xa, p2: 'mode'=0x0, p3: 'request'=0x3

  IO
  Total Self- Total Total Outlr Outlr Outlr
  Hung Rslvd Rslvd Wait WaitTm Wait WaitTm Wait
  Sess Hangs Hangs Count Secs Count Secs Count Wait Event
  ------ ------ ------ ------ ------ ------ ------ ------ -----------
  44 0 0 372200 54 0 0 0 library cache load lock

   
• The hang is due to row cache dc_user:
  => Oracle session identified by:
  {
  instance: 1
  os id: 22167
  process id: 168,
  session id: 482 <<<=====
  session serial #: 2323
  }
  which is waiting for 'row cache lock' with wait info:
  {
  p1: 'cache id'=0xa <<<===== dc_user
  p2: 'mode'=0x0
  p3: 'request'=0x3
  time in wait: 12 min 55 sec <<<=====
   

Cause

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