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Improved speed of optimizer trace

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- Added unlikely() to optimize for not having optimizer trace enabled
- Made THD::trace_started() inline
- Added 'if (trace_enabled())' around some potentially expensive code
  (not many found)
- Added ASSERT's to ensure we don't call expensive optimizer trace calls
  if optimizer trace is not enabled
- Added length to Json_writer functions to speed up buffer writes
  when optimizer trace is enabled.
- Changed LEX_CSTRING argument handling to not send full struct to writer
  function on_add_str() functions now trusts length arguments
This commit is contained in:
Monty
2020-03-06 10:33:11 +02:00
parent 1ad8693a6f
commit 940fcbe73b
9 changed files with 176 additions and 102 deletions
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43
sql/sql_select.cc
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@ -353,8 +353,10 @@ bool dbug_user_var_equals_int(THD *thd, const char *name, int value)
static void trace_table_dependencies(THD *thd,
JOIN_TAB *join_tabs, uint table_count)
{
DBUG_ASSERT(thd->trace_started());
Json_writer_object trace_wrapper(thd);
Json_writer_array trace_dep(thd, "table_dependencies");
for (uint i= 0; i < table_count; i++)
{
TABLE_LIST *table_ref= join_tabs[i].tab_list;
@ -1469,6 +1471,7 @@ JOIN::prepare(TABLE_LIST *tables_init,
}
}
if (thd->trace_started())
{
Json_writer_object trace_wrapper(thd);
opt_trace_print_expanded_query(thd, select_lex, &trace_wrapper);
@ -5352,6 +5355,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
{
Json_writer_object rows_estimation_wrapper(thd);
Json_writer_array rows_estimation(thd, "rows_estimation");
for (s=stat ; s < stat_end ; s++)
{
s->startup_cost= 0;
@ -5496,10 +5500,16 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
if (select)
delete select;
else
add_table_scan_values_to_trace(thd, s);
{
if (thd->trace_started())
add_table_scan_values_to_trace(thd, s);
}
}
else
add_table_scan_values_to_trace(thd, s);
{
if (thd->trace_started())
add_table_scan_values_to_trace(thd, s);
}
}
}
@ -7402,7 +7412,7 @@ best_access_path(JOIN *join,
Json_writer_object trace_access_idx(thd);
/*
ft-keys require special treatment
full text keys require special treatment
*/
if (ft_key)
{
@ -7414,7 +7424,7 @@ best_access_path(JOIN *join,
records= 1.0;
type= JT_FT;
trace_access_idx.add("access_type", join_type_str[type])
.add("index", keyinfo->name);
.add("full-text index", keyinfo->name);
}
else
{
@ -11866,18 +11876,21 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
i++;
}
trace_attached_comp.end();
Json_writer_array trace_attached_summary(thd,
"attached_conditions_summary");
for (tab= first_depth_first_tab(join); tab;
tab= next_depth_first_tab(join, tab))
if (unlikely(thd->trace_started()))
{
if (!tab->table)
continue;
Item *const cond = tab->select_cond;
Json_writer_object trace_one_table(thd);
trace_one_table.add_table_name(tab);
trace_one_table.add("attached", cond);
trace_attached_comp.end();
Json_writer_array trace_attached_summary(thd,
"attached_conditions_summary");
for (tab= first_depth_first_tab(join); tab;
tab= next_depth_first_tab(join, tab))
{
if (!tab->table)
continue;
Item *const cond = tab->select_cond;
Json_writer_object trace_one_table(thd);
trace_one_table.add_table_name(tab);
trace_one_table.add("attached", cond);
}
}
}
DBUG_RETURN(0);