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  1. Solution Center
  2. SOL-124

[04000] Error while evaluating filter: Compression problem detected. Try recompressing used tables. See also EXASOL-1244

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    Details

    • Type: Workaround
    • Status: Published
    • Affects Version/s: EXASolution 4.2.5
    • Fix Version/s: None
    • Component/s: EXASolution
    • Labels:
      None
    • Symptoms:
      Hide

      [04000] Error while evaluating filter: Compression problem detected. Try re-compressing used tables. See also EXASOL-1244

      Show
      [04000] Error while evaluating filter: Compression problem detected. Try re-compressing used tables. See also EXASOL-1244
    • Explanation:
      Hide

      The error message is caused by a bug at compression of varchar-columns prior to the version 4.2.5. Under some specific circumstances, the same string will be transformed internally to two different compressed presentations during an insert operation.

      Reading the value causes normally no issues as it will be decompressed into a consistent presentation.

      If there's however a simple filter like '<column> = <constant>', EXASolution works directly with compressed values to speed up the query execution.
      In this case, only the rows matching to one of the compressed representations will be found.

      The data inserted by the version 4.2.5 and above won't be affected by the bug. The version 4.2.5 also detects erroneous values and interrupts the execution displaying the error message above.

      Show
      The error message is caused by a bug at compression of varchar-columns prior to the version 4.2.5. Under some specific circumstances, the same string will be transformed internally to two different compressed presentations during an insert operation. Reading the value causes normally no issues as it will be decompressed into a consistent presentation. If there's however a simple filter like '<column> = <constant>', EXASolution works directly with compressed values to speed up the query execution. In this case, only the rows matching to one of the compressed representations will be found. The data inserted by the version 4.2.5 and above won't be affected by the bug. The version 4.2.5 also detects erroneous values and interrupts the execution displaying the error message above.
    • Solution:
      Hide

      Execute 'recompress <table>' on affected table

      Please note, that the system doesn't re-compress the affected table automatically to avoid transaction conflicts.

      Show
      Execute 'recompress <table>' on affected table Please note, that the system doesn't re-compress the affected table automatically to avoid transaction conflicts.
    • Category 1:
      SQL - Data types

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          • Assignee:
            CaptainEXA Captain EXASOL
            Reporter:
            CaptainEXA Captain EXASOL
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            Dates

            • Created:
              Updated: