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  1. MariaDB Server
  2. MDEV-6846

Test tokudb_mariadb.mdev6657 fails in buildbot (and outside)

Details

    Description

      http://buildbot.askmonty.org/buildbot/builders/kvm-bintar-quantal-amd64/builds/851/steps/test/logs/stdio

      CURRENT_TEST: tokudb_mariadb.mdev6657
      		 
      --- /usr/local/mariadb-10.1.1-linux-x86_64/mysql-test/plugin/tokudb/tokudb_mariadb/r/mdev6657.result	2014-10-06 11:54:56.000000000 +0300
      		 
      +++ /usr/local/mariadb-10.1.1-linux-x86_64/mysql-test/plugin/tokudb/tokudb_mariadb/r/mdev6657.reject	2014-10-06 16:30:44.327828045 +0300
      		 
      @@ -34,7 +34,7 @@
      		 
       where col1 <= 1410799999 
       order by col1 desc,col2 desc,col3 desc limit 1;
      		 
       id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
      		 
      -1	SIMPLE	t3	range	PRIMARY,key1	PRIMARY	4	NULL	2001	Using where; Using index
      		 
      +1	SIMPLE	t3	range	PRIMARY,key1	key1	4	NULL	2001	Using where; Using index
      		 
       # The same query but the constant is bigger. 
       # The query should use range(PRIMARY), not full index scan:
      		 
       explain 
      @@ -43,5 +43,5 @@
      		 
       where col1 <= 1412199999 
       order by col1 desc, col2 desc, col3 desc limit 1;
      		 
       id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
      		 
      -1	SIMPLE	t3	range	PRIMARY,key1	PRIMARY	4	NULL	15001	Using where; Using index
      		 
      +1	SIMPLE	t3	range	PRIMARY,key1	key1	4	NULL	15001	Using where; Using index
      		 
       drop table t1,t2,t3;

      I got the same failure while running the single test on my machine.

      Attachments

        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-6657 Poor plan choice for ORDER BY key DESC optimization and possible range access

          • Major - Major loss of function.
          • Closed

          Activity

            psergei Sergei Petrunia added a comment -

            Debugging current 10.1 (=new)and 10.1 right after the fix for MDEV-6657 (=old), looking for
            differences.

            They start at test_if_skip_sort_order()/ test_if_order_by_key(idx=1) call.

            • in old code test_if_order_by_key() returns 0 (means' its not ordered)
            • new code returns -1 (means reverse ordered).

            we have 

               PRIMARY KEY (col1,col2,col3),
            		 
               KEY key1 (col1,col2) 
            ...
            		 
            where col1 <= 1412199999 
            order by 
               col1 desc, 
               col2 desc, 
               col3 desc limit 1;

            indeed, "key1" produces the required ordering. Old code is unable to recognize
            it, because it doesn't have this fix:

            MDEV-6796: Unable to skip filesort when using implicit extended key
            		 
             
            		 
            Re-work test_if_order_by_key() to work correctly for extended indexes.

            psergei Sergei Petrunia added a comment - Debugging current 10.1 (=new)and 10.1 right after the fix for MDEV-6657 (=old), looking for differences. They start at test_if_skip_sort_order()/ test_if_order_by_key(idx=1) call. in old code test_if_order_by_key() returns 0 (means' its not ordered) new code returns -1 (means reverse ordered). we have PRIMARY KEY (col1,col2,col3), KEY key1 (col1,col2) ... where col1 <= 1412199999 order by col1 desc, col2 desc, col3 desc limit 1; indeed, "key1" produces the required ordering. Old code is unable to recognize it, because it doesn't have this fix: MDEV-6796: Unable to skip filesort when using implicit extended key   Re-work test_if_order_by_key() to work correctly for extended indexes.

            People

              psergei Sergei Petrunia
              elenst Elena Stepanova
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              Dates

                Created:
                Updated:
                Resolved:

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