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  1. Percona Toolkit
  2. PT-1728

Pt-table-checksum failing to scan small tables that get wiped out often

    Details

    • Type: Bug
    • Status: Pending Release
    • Priority: Medium
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 3.1.0
    • Component/s: None
    • Labels:
      None

      Description

      Hi, I have a small table that is often cleared/truncated. And it looks like the pt-table-checksum I am running to checksum that hits a race condition and fails to scan the table.

      NOTE: I am running a pt-table-checksum with patches from another ticket to force nibble all the tables that have more than 1 row. The patch never made it to released version, so this is a locally applied patch. The exact pt-table-checksum binary I am using is attached.

      The sequence is -

      • pt-table-checksum notices 2 rows in that table.
      • It decides to nibble the table
      • The table gets wiped out
      • pt-table-checksum tries to figure out lower/upper boundary for nibbling
      • Hits a bug in Perl code
        ```
        Error checksumming table edgestore_shard01000010011.edgedata_xtxn: Can't use an undefined value as an ARRAY reference at /srv/yaps/mounts/percona_toolkit/default/8ca5d17c0d8f6af3974777f607d682af1ea0f5e9-c7e383000995dc78359ac2e9f26287f2/pt_table_checksum_wrapper.runfiles/_main_/dropbox/database_ops/pt_tc/pt-table-checksum line 11497.
        ```

      I am 99% sure this is the sequence that causes it to crash. It will be great if a pt-table-checksum developer can take a quick look at this and give thought. I don't have a repro'able case.

      MySQL version is 5.6, pt-table-checksum is forked from vs 3.0.9.

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              • Assignee:
                carlos.salguero Carlos Salguero
                Reporter:
                carlos.salguero Carlos Salguero
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