Affects Version/s: None
Fix Version/s: None
**Reported in Launchpad by Aleksandr Kuzminsky last update 11-11-2014 06:34:17
pt-table-checksum does two basic operations:
1. "UPDATE $repl_table SET chunk_time = ?, master_crc = ?, master_cnt = ? "
2. "REPLACE INTO $repl_table ... this_cnt, this_crc'
i.e. the first sets master_* fields and the second - this_* fields.
Due to a fact that these two are done as separate transactions for short period of time the row on a slave is inconsistent.
master_* fields are set, but this_* are not yet.
This may cause false positive triggers of monitoring software.
As a solution UPDATE and REPLACE may be wrapped into BEGIN/COMMIT, so the change of a row on a slave is atomic.