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  2. SOL-95

Update to EXASuite 5.0: REORGANIZE DATABASE

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    • Type: How To
    • Status: Published
    • Affects Version/s: EXASolution 5.0
    • Fix Version/s: None
    • Component/s: EXASolution
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      After the update to EXASuite 5.0 an executing of a REORGANIZE DATABASE command is strongly recommend.

      In the version 5 we reworked indices to speed up their creation and to reduce the memory consumption. Due to this rework, the indices created by the version 4 cannot be used anymore.

      When starting for the first time after the update to the version 5, the database invalidates all the indices. To avoid the "on-the-fly" recreation during query execution, please consider executing of a "REORGANIZE DATABASE" command shortly after the first startup with the version 5. This statement will ensure that all the indices will be recreated.

      An additional benefit of running the REORGANIZE DATABASE will be an explicit redistribution of tables being previously distributed by string columns (SQL type CHAR or VARCHAR). Such distributions will be invalidated automatically during the first start of the version 5, because of improvements on corresponding algorithms. The redistribution won't be conducted "on-the-fly", which can cause for example a global join instead of a local one with corresponding performance draw backs.

      Please note, that if you have to run REORGANIZE DATABASE after updating of 5.0.1 to 5.0.3, you would additionally need ENFORCE keyword:

      REORGANIZE DATABASE ENFORCE;
      
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      After the update to EXASuite 5.0 an executing of a REORGANIZE DATABASE command is strongly recommend. In the version 5 we reworked indices to speed up their creation and to reduce the memory consumption. Due to this rework, the indices created by the version 4 cannot be used anymore. When starting for the first time after the update to the version 5, the database invalidates all the indices. To avoid the "on-the-fly" recreation during query execution, please consider executing of a "REORGANIZE DATABASE" command shortly after the first startup with the version 5. This statement will ensure that all the indices will be recreated. An additional benefit of running the REORGANIZE DATABASE will be an explicit redistribution of tables being previously distributed by string columns (SQL type CHAR or VARCHAR). Such distributions will be invalidated automatically during the first start of the version 5, because of improvements on corresponding algorithms. The redistribution won't be conducted "on-the-fly", which can cause for example a global join instead of a local one with corresponding performance draw backs. Please note, that if you have to run REORGANIZE DATABASE after updating of 5.0.1 to 5.0.3, you would additionally need ENFORCE keyword: REORGANIZE DATABASE ENFORCE;
    • Category 1:
      Database Administration - Data Organization
    • Category 2:
      Cluster Administration - Update

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            • Assignee:
              CaptainEXA Captain EXASOL
              Reporter:
              CaptainEXA Captain EXASOL
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