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  1. MariaDB Server
  2. MDEV-5387

Assertion `0' fails in Item_equal::get_first with materialization+semijoin, EXPLAIN, IN subquery

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Minor
    • Resolution: Won't Fix
    • 5.3.12, 5.5.34, 10.0.6
    • N/A
    • Optimizer
    • None

    Description

      I've set it to 'Minor' because there is a rather senseless condition in WHERE, so it can be considered a corner case, and because it's a debug assertion only

      mysqld: item_cmpfunc.cc:6138: Item* Item_equal::get_first(JOIN_TAB*, Item*): Assertion `0' failed.
      131205  1:37:51 [ERROR] mysqld got signal 6 ;

      #6  0x00007f181a616621 in *__GI___assert_fail (assertion=0xc6b59c "0", file=<optimized out>, line=6138, function=0xc6c360 "Item* Item_equal::get_first(JOIN_TAB*, Item*)") at assert.c:81
      #7  0x00000000005ffd70 in Item_equal::get_first (this=0x23214b0, context=0x2324eb8, field_item=0x229bcd8) at item_cmpfunc.cc:6138
      #8  0x00000000005acbaf in Item_field::replace_equal_field (this=0x229bcd8, arg=0x7f1811b32520 "\260\024\062\002") at item.cc:5155
      #9  0x00000000005a0f03 in Item::transform (this=0x229bcd8, transformer=&virtual Item::replace_equal_field(unsigned char*), arg=0x7f1811b32520 "\260\024\062\002") at item.cc:725
      #10 0x0000000000746398 in substitute_for_best_equal_field (context_tab=0x2324eb8, cond=0x229bcd8, cond_equal=0x2321218, table_join_idx=0x2322a50) at sql_select.cc:12254
      #11 0x0000000000729405 in JOIN::optimize (this=0x22cf8c8) at sql_select.cc:1299
      #12 0x000000000072f58b in mysql_select (thd=0x2216bc8, rref_pointer_array=0x22198b8, tables=0x229aba8, wild_num=1, fields=..., conds=0x22ceb38, og_num=0, order=0x0, group=0x0, having=0x0, proc_param=0x0, select_options=2147764740, result=0x22cf208, unit=0x2219158, select_lex=0x2219660) at sql_select.cc:2995
      #13 0x0000000000760c84 in mysql_explain_union (thd=0x2216bc8, unit=0x2219158, result=0x22cf208) at sql_select.cc:22377
      #14 0x00000000006b4bdf in execute_sqlcom_select (thd=0x2216bc8, all_tables=0x229aba8) at sql_parse.cc:5151
      #15 0x00000000006abf18 in mysql_execute_command (thd=0x2216bc8) at sql_parse.cc:2305
      #16 0x00000000006b76e3 in mysql_parse (thd=0x2216bc8, rawbuf=0x229a900 "EXPLAIN \nSELECT * FROM t1, t2, t3\nWHERE c = a AND ( e, c )  IN ( SELECT e, e FROM t3 )\nAND b IS NULL AND b = 'Midland'", length=118, found_semicolon=0x7f1811b33cb8) at sql_parse.cc:6173
      #17 0x00000000006a96f8 in dispatch_command (command=COM_QUERY, thd=0x2216bc8, packet=0x2291499 "", packet_length=118) at sql_parse.cc:1243
      #18 0x00000000006a89e4 in do_command (thd=0x2216bc8) at sql_parse.cc:923
      #19 0x00000000006a586d in handle_one_connection (arg=0x2216bc8) at sql_connect.cc:1231
      #20 0x00007f181b322b50 in start_thread (arg=<optimized out>) at pthread_create.c:304
      #21 0x00007f181a6c5a7d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112

      revision-id: bar@mnogosearch.org-20131203110843-1bsdu0hcrpzhie8w
      revno: 3731
      branch-nick: 5.3
      BUILD/compile-pentium-debug-max-no-ndb

      SET optimizer_switch='materialization=on,semijoin=on';
       
      CREATE TABLE t1 (a VARCHAR(52));
      INSERT INTO t1 VALUES ('USA'),('CAN');
       
      CREATE TABLE t2 (b VARCHAR(52), c VARCHAR(52), INDEX(b));
      INSERT INTO t2 VALUES ('Mesa','USA'),('Chesapeake','USA');
       
      CREATE TABLE t3 (d INT, e VARCHAR(3), f VARCHAR(35), INDEX(e,f));
      INSERT INTO t3 VALUES 
      (1,'USA','Cedar Rapids'),
      (2,'USA','Chandler'),
      (3,'USA','Charleston'),
      (4,'USA','Charlotte'),
      (5,'USA','Chattanooga'),
      (6,'USA','Chesapeake'),
      (7,'USA','Chicago'),
      (8,'USA','Chula Vista'),
      (9,'USA','Cincinnati'),
      (10,'USA','Mesa'),
      (11,'USA','Mesquite'),
      (12,'USA','Metairie'),
      (13,'USA','Miami'),
      (14,'USA','Miami Beach'),
      (15,'USA','Midland');
       
      EXPLAIN 
      SELECT * FROM t1, t2, t3
      WHERE c = a AND ( e, c )  IN ( SELECT e, e FROM t3 )
      AND b IS NULL AND b = 'Midland';

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            psergei Sergei Petrunia
            elenst Elena Stepanova
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              Created:
              Updated:
              Resolved:

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