Bug #53561 HA_EXTRA_WRITE_CAN_REPLACE does not work with row based replication

• Submitted: 11 May 2010 12:20
• Modified: 14 May 2010 15:04
• Reporter: Zardosht Kasheff (OCA)
• Status: Verified
• Category: MySQL Server
• Severity: S3 (Non-critical)
• Version: 5.1.46, 5.5
• OS: Any
• Assigned to: Assigned Account
• CPU Architecture: Any

[11 May 2010 12:20] Zardosht Kasheff

Description:
Bug filed as result of this discussion on internals list: http://lists.mysql.com/internals/37907

The flag HA_EXTRA_WRITE_CAN_REPLACE, according to the comments, means:
  /*
    Informs handler that write_row() which tries to insert new row into the
    table and encounters some already existing row with same primary/unique
    key can replace old row with new row instead of reporting error (basically
    it informs handler that we do REPLACE instead of simple INSERT).
    Off by default.
  */

If on a master, the storage engine finds a duplicate, and decides to replace the old row with the new row, then replication will fail on the slave. The slave will not know that a replace is occurring, and will encounter a duplicate key error.

How to repeat:
n/a

Suggested fix:
Enough information should be stored in row based replication to simulate a replace. If the master has the flag HA_EXTRA_WRITE_CAN_REPLACE set, then this should be saved in the binary log, and the slave should know that if a duplicate key error is found, that a replace should occur.

[14 May 2010 15:04] Susanne Ebrecht

Many thanks for writing a bug report.

Verified as described and by reading comments from Mats.