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  1. Percona Server for MySQL
  2. PS-4315

Index cardinality stats updated for handler::info(HA_STATUS_CONST), not often enough for tokudb_cardinality_scale_percent

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    Details

    • Type: Bug
    • Status: Done
    • Priority: Medium
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 5.6.38-83.0, 5.7.20-18
    • Component/s: TokuDB
    • Labels:
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      Description

      Usually, for a MySQL storage engine, index cardinality stats (rec_per_key) are considered a part of "constant" table information, and so are updated on handler::info(HA_STATUS_CONST) call. However, TokuDB may return different rec_per_key values depending on the dynamic variable tokudb_cardinality_scale_percent value. The server does not have a way of knowing that changing this variable invalidates the previous rec_per_key values in any opened table shares, and so does not call info(HA_STATUS_CONST) again.

      It seems more correct to update share rec_per_key on info(HA_STATUS_VARIABLE) calls too.

      This is exposed by adapting https://bugs.launchpad.net/percona-server/+bug/1704195 for TokuDB

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              Assignee:
              laurynas.biveinis Laurynas Biveinis (Inactive)
              Reporter:
              laurynas.biveinis Laurynas Biveinis (Inactive)
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