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MDEV-36106 New-style hints: [NO_]DERIVED_CONDITION_PUSHDOWN, [NO_]MERGE

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Implements and tests the optimizer hints DERIVED_CONDITION_PUSHDOWN
and NO_DERIVED_CONDITION_PUSHDOWN, table-level hints to enable and
disable, respectively, the condition pushdown for derived tables
which is typically controlled by the condition_pushdown_for_derived
optimizer switch.

Implements and tests the optimizer hints MERGE and NO_MERGE, table-level
hints to enable and disable, respectively, the derived_merge optimization
which is typically controlled by the derived_merge optimizer switch.

Sometimes hints need to be fixed before TABLE instances are available, but
after TABLE_LIST instances have been created (as in the cases of MERGE and
NO_MERGE).  This commit introduces a new function called
fix_hints_for_derived_table to allow early hint fixing for derived tables,
using only a TABLE_LIST instance (so long as such hints are not index-level).
This commit is contained in:
Dave Gosselin
2025-02-24 11:32:27 -05:00
committed by Dave Gosselin
parent e653666368
commit 2ee2e2d0f3
10 changed files with 3367 additions and 41 deletions
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55
sql/sql_select.cc
View File

@@ -2513,43 +2513,42 @@ JOIN::optimize_inner()
DBUG_RETURN(TRUE);
}
if (optimizer_flag(thd, OPTIMIZER_SWITCH_COND_PUSHDOWN_FOR_DERIVED))
TABLE_LIST *tbl;
List_iterator_fast<TABLE_LIST> li(select_lex->leaf_tables);
while ((tbl= li++))
{
TABLE_LIST *tbl;
List_iterator_fast<TABLE_LIST> li(select_lex->leaf_tables);
while ((tbl= li++))
const bool is_derived_pushdown_allowed= hint_table_state(
thd, tbl->table, DERIVED_CONDITION_PUSHDOWN_HINT_ENUM,
optimizer_flag(thd, OPTIMIZER_SWITCH_COND_PUSHDOWN_FOR_DERIVED));
if (!is_derived_pushdown_allowed)
{
/*
/* Run optimize phase on this derived table/view. */
if (tbl->is_view_or_derived() &&
tbl->handle_derived(thd->lex, DT_OPTIMIZE))
DBUG_RETURN(1);
continue;
}
if (tbl->is_materialized_derived())
{
JOIN *join= tbl->get_unit()->first_select()->join;
if (join &&
join->optimization_state == JOIN::OPTIMIZATION_PHASE_1_DONE &&
join->with_two_phase_optimization)
continue;
/*
Do not push conditions from where into materialized inner tables
of outer joins: this is not valid.
*/
if (tbl->is_materialized_derived())
if (!tbl->is_inner_table_of_outer_join())
{
JOIN *join= tbl->get_unit()->first_select()->join;
if (join &&
join->optimization_state == JOIN::OPTIMIZATION_PHASE_1_DONE &&
join->with_two_phase_optimization)
continue;
/*
Do not push conditions from where into materialized inner tables
of outer joins: this is not valid.
*/
if (!tbl->is_inner_table_of_outer_join())
{
if (pushdown_cond_for_derived(thd, conds, tbl))
DBUG_RETURN(1);
}
if (mysql_handle_single_derived(thd->lex, tbl, DT_OPTIMIZE))
DBUG_RETURN(1);
if (pushdown_cond_for_derived(thd, conds, tbl))
DBUG_RETURN(1);
}
if (mysql_handle_single_derived(thd->lex, tbl, DT_OPTIMIZE))
DBUG_RETURN(1);
}
}
else
{
/* Run optimize phase for all derived tables/views used in this SELECT. */
if (select_lex->handle_derived(thd->lex, DT_OPTIMIZE))
DBUG_RETURN(1);
}
{
if (select_lex->where)
{