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Bug#32149: Long semaphore wait for adaptive hash latch

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Holding on to the temporary inno hash index latch is an optimization in
many cases, but a pessimization in some others.

Release temporary latches for those corner cases we (or rather, or customers,
thanks!) have identified, that is, when we are about to do something that
might take a really long time, like REPAIR or filesort.

sql/ha_myisam.cc:
  Let go of (inno, for now) latch when doing MyISAM-repair.
  (optimize passes through repair.) ("Stuck" in "Repair with
  keycache".)
sql/sql_insert.cc:
  Let go of (inno, for now) latch when doing CREATE...SELECT
  in select_insert::send_data() -- it might take a while.
  ("stuck" in "Sending data")
sql/sql_select.cc:
  Release temporary (inno, for now) latch on
  - free_tmp_table() (this can take surprisingly long, "removing tmp table")
  - create_myisam_from_heap() (HEAP table overflowing onto disk as MyISAM,
    "converting HEAP to MyISAM")
This commit is contained in:
Tatiana A. Nurnberg 2009-06-05 00:23:08 +02:00
parent 8041311e24
commit e34085fe13
3 changed files with 13 additions and 0 deletions
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3
sql/ha_myisam.cc
View File

@ -1009,6 +1009,9 @@ int ha_myisam::repair(THD *thd, MI_CHECK &param, bool do_optimize)
param.out_flag= 0;
strmov(fixed_name,file->filename);
// Release latches since this can take a long time
ha_release_temporary_latches(thd);
// Don't lock tables if we have used LOCK TABLE
if (!thd->locked_tables &&
mi_lock_database(file, table->s->tmp_table ? F_EXTRA_LCK : F_WRLCK))

3
sql/sql_insert.cc
View File

@ -2935,6 +2935,9 @@ bool select_insert::send_data(List<Item> &values)
}
}
// Release latches in case bulk insert takes a long time
ha_release_temporary_latches(thd);
error= write_record(thd, table, &info);
table->auto_increment_field_not_null= FALSE;

7
sql/sql_select.cc
View File

@ -10226,6 +10226,9 @@ free_tmp_table(THD *thd, TABLE *entry)
save_proc_info=thd->proc_info;
thd_proc_info(thd, "removing tmp table");
// Release latches since this can take a long time
ha_release_temporary_latches(thd);
if (entry->file)
{
if (entry->db_stat)
@ -10274,6 +10277,10 @@ bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
table->file->print_error(error,MYF(0));
DBUG_RETURN(1);
}
// Release latches since this can take a long time
ha_release_temporary_latches(thd);
new_table= *table;
new_table.s= &new_table.share_not_to_be_used;
new_table.s->db_type= DB_TYPE_MYISAM;