Uploaded image for project: 'MariaDB Server'
  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

        • Type: Bug
        • Status: Closed
        • Priority: Minor
        • Resolution: Fixed
        • Affects Version/s: None
        • Fix Version/s: 5.5.25
        • Component/s: None
        • Labels:
          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.

            Gliffy Diagrams

              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-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-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

                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-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

                  Activity

                  Ascending order - Click to sort in descending order
                  Hide
                  Permalink
                  timour Timour Katchaounov 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.

                  Show
                  timour Timour Katchaounov 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.
                  Hide
                  Permalink
                  timour Timour Katchaounov added a comment -
                  • Analyzed EXPLAIN differences due to merge
                  • Finished mere, pushed into 5.5.25.
                  Show
                  timour Timour Katchaounov added a comment - Analyzed EXPLAIN differences due to merge Finished mere, pushed into 5.5.25.

                    People

                    • Assignee:
                      timour Timour Katchaounov
                      Reporter:
                      elenst Elena Stepanova
                    • Votes:
                      0 Vote for this issue
                      Watchers:
                      1 Start watching this issue

                      Dates

                      • Created:
                        Updated:
                        Resolved:

                        Time Tracking

                        Estimated:
                        Original Estimate - 2 days, 2 hours Original Estimate - 2 days, 2 hours
                        2d 2h
                        Remaining:
                        Remaining Estimate - 0 minutes
                        0m
                        Logged:
                        Time Spent - 1 week, 3 days, 6 hours, 30 minutes
                        1w 3d 6h 30m