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MDEV-22535 TABLE::initialize_quick_structures() takes 0.5% in oltp_read_only

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Fixed by:
- Make all quick_* variable allocated according to real number keys instead
  of MAX_KEY
- Store all the quick* items in separated allocated structure (OPT_RANGE)
- Ensure we don't access any quick* variable without first checking
  opt_range_keys.is_set().  Thanks to this, we don't need any
  pre-initialization of quick* variables anymore.

Some renames was done to use the new structure:
table->quick_keys                -> table->opt_range_keys
table->quick_rows[X]             -> table->opt_range[X].rows
table->quick_key_parts[X]        -> table->opt_range[X].key_parts
table->quick_costs[X]            -> table->opt_range[X].cost
table->quick_index_only_costs[X] -> table->opt_range[X].index_only_cost
table->quick_n_ranges[X]         -> table->opt_range[X].ranges
table->quick_condition_rows      -> table->opt_range_condition_rows

This patch should both decrease memory needed for TABLE objects
(3528 -> 984 + keyinfo) and increase performance, thanks to less
initializations per query, and more localized memory, thanks to the
opt_range structure.
This commit is contained in:
Monty
2020-06-26 01:47:33 +03:00
parent 5cbb18cb44
commit 6cee9b1953
8 changed files with 181 additions and 146 deletions
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4
sql/sql_update.cc
View File

@ -443,7 +443,7 @@ int mysql_update(THD *thd,
/* Calculate "table->covering_keys" based on the WHERE */
table->covering_keys= table->s->keys_in_use;
table->quick_keys.clear_all();
table->opt_range_keys.clear_all();
query_plan.select_lex= thd->lex->first_select_lex();
query_plan.table= table;
@ -577,7 +577,7 @@ int mysql_update(THD *thd,
}
/* If running in safe sql mode, don't allow updates without keys */
if (table->quick_keys.is_clear_all())
if (table->opt_range_keys.is_clear_all())
{
thd->set_status_no_index_used();
if (safe_update && !using_limit)