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  1. Percona Server
  2. PS-1852

LP #743801: inserts and updates to MRG_MYISAM table not tracked in TABLE_STATISTICS

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    Details

    • Type: Bug
    • Status: On Hold
    • Priority: Low
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None

      Description

      **Reported in Launchpad by Dan Edwards last update 17-03-2016 13:27:32

      I just upgraded from mysql 5.0 to percona 5.1.55. I noticed that TABLE_STATISTICS.ROWS_CHANGED was 0 for some of our busiest tables. I narrowed it down too those tables were using the MRG_MYISAM engine. It did not record ROWS_CHANGED for either the merge table or the underlying MYISAM tables.

      Here is sql to reproduce:

      CREATE TABLE mrg_tbl1 (id INT(11) NOT NULL AUTO_INCREMENT, field1 INT(11) NULL DEFAULT NULL, PRIMARY KEY (id)) ENGINE=MYISAM;

      CREATE TABLE mrg_tbl2 (id INT(11) NOT NULL AUTO_INCREMENT, field1 INT(11) NULL DEFAULT NULL, PRIMARY KEY (id)) ENGINE=MYISAM;

      CREATE TABLE mrg_tbl ( id INT(11) NOT NULL AUTO_INCREMENT, field1 INT(11) NULL DEFAULT NULL, PRIMARY KEY (id)) ENGINE=MRG_MYISAM UNION=(mrg_tbl1, mrg_tbl2) INSERT_METHOD=LAST;

      insert into mrg_tbl (field1) Values(10),(11),(12) ;
      update mrg_tbl set field1=20 where field1=10;

      select * from mrg_tbl;

      select * from information_schema.TABLE_STATISTICS where TABLE_NAME like "mrg_tbl%"

      Notice that it adds a row for mrg_tbl2 with ROWS_READ=3, ROWS_CHANGED=0.

      These are our busiest tables and I really wanted to see statistics for them

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              • Assignee:
                Unassigned
                Reporter:
                lpjirasync lpjirasync (Inactive)
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                • Created:
                  Updated: