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  1. MariaDB Server
  2. MDEV-193

LP:944706 - Query with impossible or constant subquery in WHERE or HAVING is not precomputed and thus not part of optimization

Details

    • Bug
    • Status: Closed (View Workflow)
    • Minor
    • Resolution: Fixed
    • None
    • 5.5.25
    • None
    • None

    Description

      https://bugs.launchpad.net/maria/+bug/944706

      This is not a new bug, but it has been recently switched from milestone 5.3 to 5.5, so it needs an entry in JIRA.
      Fix version 5.5.23 is temporary.

      Attachments

        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-277 CHEAP SQ: Server crashes in st_join_table::get_examined_rows with semijoin+materialization, IN and = subqueries

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-287 CHEAP SQ: A query with subquery in SELECT list, EXISTS, inner joins takes hundreds times longer

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-288 CHEAP SQ: Valgrind warnings "Memory lost" with IN and EXISTS nested subquery, materialization+semijoin

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-311 CHEAP SQ: Inconsistent behavior of subquery in SELECT and HAVING

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-312 CHEAP SQ: A query with LEFT JOIN in outer SELECT and INNER JOIN and aggregate in subquery takes much longer than on the main tree

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-317 CHEAP SQ: A query with EXISTS subquery, aggregate function in subquery, ORDER BY and LIMIT takes much longer than on main tree if optimizer_prune_level=0

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-321 CHEAP SQ: A query with inner joins and EXISTS subquery takes several times longer on MDEV-193 tree than on 5.5 main tree

          • Major - Major loss of function.
          • Closed

          Activity

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            timour Timour Katchaounov (Inactive) added a comment -

            Fixed all crashes resulting from enabling back subquery execution during query optimization.
            The result of the fixes is that now I need to find a new solution for bug https://bugs.launchpad.net/maria/+bug/944504, because its current fix is to forbid subquery evaluation during optimization.

            After fixing this remaining crash (bug lp:944504), there are several wrong results to be fixed.
            After that, the patch needs improvement in how we detect if a subquery is expensive, and to refine two of the fixes for EXPLAIN-specific crashes.

            timour Timour Katchaounov (Inactive) added a comment - Fixed all crashes resulting from enabling back subquery execution during query optimization. The result of the fixes is that now I need to find a new solution for bug https://bugs.launchpad.net/maria/+bug/944504 , because its current fix is to forbid subquery evaluation during optimization. After fixing this remaining crash (bug lp:944504), there are several wrong results to be fixed. After that, the patch needs improvement in how we detect if a subquery is expensive, and to refine two of the fixes for EXPLAIN-specific crashes.
            timour Timour Katchaounov (Inactive) added a comment -
            • Analyzed EXPLAIN differences due to merge
            • Finished mere, pushed into 5.5.25.
            timour Timour Katchaounov (Inactive) added a comment - Analyzed EXPLAIN differences due to merge Finished mere, pushed into 5.5.25.

            People

              timour Timour Katchaounov (Inactive)
              elenst Elena Stepanova
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              Dates

                Created:
                Updated:
                Resolved:

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