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  1. MariaDB Server
  2. MDEV-22211

case senitivity behavior not as shown by server, by db, by table, by connection

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Trivial
    • Resolution: Not a Bug
    • None
    • N/A
    • Character Sets

    Description

      environment:

      • i'm connected by mysql on the local linux machine
      • database was created by this version mariadb - no migration
      • table was created by this server default configuration .. <utf8mb4_general_ci>
      • sometimes later added to server configuration:
        <collation_server=utf8mb4_bin>
        <init-connect ='SET NAMES utf8mb4, collation_connection = utf8mb4_bin'

      test: select cdgrp,tshort,tlong from t_config where tshort = 'xau';
      result: | Currency | XAU | Gold |
      expected: Empty set
      fix with: alter table t_config convert to character set utf8mb4 collate utf8mb4_bin;

      redo test after drop table, create it newly (with changed server configuration)
      test: select cdgrp,tshort,tlong from t_config where tshort = 'xau';
      result: Empty set

      conclusion: just changing collation in server configuration does show up everything ok. but the engine behave not as expected. it need's an alter table to set everything correct - changing server configuration does not.

      after fix: select cdgrp, tshort from t_config where cdgrp = 'CDGRP' return empty dataset
      analyzing proceedure (see details in analyze.txt)

      • analze table ok;
      • find all tuples not using index
        fix: drop / create index

      conclusion: alter table convert character set and collation does fix the issue but can leave inconsistent indexes behind. any checks on table structure do not recognise inkonsistency.

      have fun

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            Unassigned Unassigned
            SwissGeorge Juerg Oehler
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            Dates

              Created:
              Updated:
              Resolved:

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