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BUG#834534: Assertion `0' failed in replace_where_subcondition with semijoin subquery in HAVING

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- The problem was that the code that made the check whether the subquery is an AND-part of the WHERE 
  clause didn't work correctly for nested subqueries. In particular, grand-child subquery in HAVING was 
  treated as if it was in the WHERE, which eventually caused an assert when replace_where_subcondition
  looked for the subquery predicate in the WHERE and couldn't find it there.

- The fix: Removed implementation of "thd_marker approach". thd->thd_marker was used to determine the 
  location of subquery predicate: setup_conds() would set accordingly it when making the 

    {where|on_expr}->fix_fields(...)

  call so that AND-parts of the WHERE/ON clauses can determine they are the AND-parts. 
  Item_cond_or::fix_fields(), Item_func::fix_fields(), Item_subselect::fix_fields (this one was missed),
  and all other items-that-contain-items had to reset thd->thd_marker before calling fix_fields() for 
  their children items, so that the children can see they are not AND-parts of WHERE/ON.
- The "thd_marker approach" required that a lot of code in different locations maintains correct value of
  thd->thd_marker, so it was replaced with:
- The new approach with mark_as_condition_AND_part does not keep context in thd->thd_marker. Instead, 
  setup_conds() now calls

    {where|on_expr}->mark_as_condition_AND_part()

  and implementations of that function make sure that: 
   - parts of AND-expressions get the mark_as_condition_AND_part() call
   - Item_in_subselect objects record that they are AND-parts of WHERE/ON
This commit is contained in:
Sergey Petrunya
2011-08-29 19:57:41 +04:00
parent 2df1914791
commit 945a595aa3
14 changed files with 96 additions and 36 deletions
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7
sql/sql_base.cc
View File

@@ -8276,7 +8276,6 @@ int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
SELECT_LEX *select_lex= thd->lex->current_select;
Query_arena *arena= thd->stmt_arena, backup;
TABLE_LIST *table= NULL; // For HP compilers
TABLE_LIST *save_emb_on_expr_nest= thd->thd_marker.emb_on_expr_nest;
List_iterator<TABLE_LIST> ti(leaves);
/*
it_is_update set to TRUE when tables of primary SELECT_LEX (SELECT_LEX
@@ -8317,7 +8316,6 @@ int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
goto err_no_arena;
}
thd->thd_marker.emb_on_expr_nest= NO_JOIN_NEST;
if (*conds)
{
thd->where="where clause";
@@ -8331,11 +8329,11 @@ int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
*/
if ((*conds)->type() == Item::FIELD_ITEM && !derived)
wrap_ident(thd, conds);
(*conds)->mark_as_condition_AND_part(NO_JOIN_NEST);
if ((!(*conds)->fixed && (*conds)->fix_fields(thd, conds)) ||
(*conds)->check_cols(1))
goto err_no_arena;
}
thd->thd_marker.emb_on_expr_nest= save_emb_on_expr_nest;
/*
Apply fix_fields() to all ON clauses at all levels of nesting,
@@ -8351,8 +8349,8 @@ int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
if (embedded->on_expr)
{
/* Make a join an a expression */
thd->thd_marker.emb_on_expr_nest= embedded;
thd->where="on clause";
embedded->on_expr->mark_as_condition_AND_part(embedded);
if ((!embedded->on_expr->fixed &&
embedded->on_expr->fix_fields(thd, &embedded->on_expr)) ||
embedded->on_expr->check_cols(1))
@@ -8376,7 +8374,6 @@ int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
}
}
}
thd->thd_marker.emb_on_expr_nest= save_emb_on_expr_nest;
if (!thd->stmt_arena->is_conventional())
{