Oracle — Table lock modes

Franck Pachot
1 min readJan 18, 2019

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Here is a post with a few links to previous blog/article/video about Oracle table lock modes. And remember that in 12cR2 the event 10704 has been replaced by UTS tracing:

alter session set events 'trace[ksq] disk medium';

1. An explanation of the compatibility matrix (RS, RX, Share, SSX, X):

2. the KSD tracing to see which locks are acquired:

3. A presentation on table locks:

Agenda was:

  • 0:45 — Basics
  • 5:03 — TX lock demo
  • 9:30 — TM lock info
  • 21:04 — Foreign key index demo
  • 28:48–10g, 11g, 12c locking differences
  • 41:50 — New online operations in 12c
  • 46:26 — Event 10704 trace
  • 50:34 — Deadlock demo
  • 53:42 — Q&A

The slides seem to be there:

4. An article on lock modes:

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Franck Pachot
Franck Pachot

Written by Franck Pachot

Developer Advocate for YugabyteDB (Open-Source, PostgreSQL-compatible Distributed SQL Database. Oracle Certified Master and AWS Data Hero.

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