From 2a7cf59fc92ce322671bb687e2941275dd23d1c5 Mon Sep 17 00:00:00 2001 From: unknown Date: Tue, 31 Oct 2006 17:31:56 -0800 Subject: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Allocation of memory for the sort buffer at each evaluation of a subquery may take a significant amount of time if the buffer is rather big. With the fix we allocate the buffer at the first evaluation of the subquery and reuse it at each subsequent evaluation. mysql-test/r/subselect.result: Added a test case for bug #21727. mysql-test/t/subselect.test: Added a test case for bug #21727. sql/item_subselect.h: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Added an implementation for Item_subselect::is_uncacheable() returning TRUE if the engine if the subselect is uncacheable. sql/mysql_priv.h: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Added a new boolean parameter to the filesort_free_buffers procedure. If the value of this parameter is TRUE the procedure frees the sort_keys buffpek buffers. sql/records.cc: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Added a new boolean parameter to the filesort_free_buffers procedure. If the value of this parameter is TRUE the procedure frees the sort_keys buffpek buffers. sql/sql_base.cc: Fixed bug #21727. Made sure that st_table::pos_in_table_list would be always initialized. sql/sql_select.cc: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Added a new boolean parameter to the filesort_free_buffers procedure. If the value of this parameter is TRUE the procedure frees the sort_keys buffpek buffers. sql/sql_show.cc: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Added a new boolean parameter to the filesort_free_buffers procedure. If the value of this parameter is TRUE the procedure frees the sort_keys buffpek buffers. sql/sql_table.cc: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Cleanup. sql/table.cc: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Added st_table_list::in_subselect() returning for a table the subselect that contains the FROM list this table is taken from (if there is any). sql/table.h: Fixed bug #21727. This is a performance issue for queries with subqueries evaluation of which requires filesort. Added fields for sort_keys and buffpek buffers to the FILESORT_INFO structure. --- sql/filesort.cc | 41 ++++++++++++++++++++++++++++++++++------- 1 file changed, 34 insertions(+), 7 deletions(-) (limited to 'sql/filesort.cc') diff --git a/sql/filesort.cc b/sql/filesort.cc index f13354d5c72..6e74d978eda 100644 --- a/sql/filesort.cc +++ b/sql/filesort.cc @@ -109,6 +109,8 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length, DBUG_PUSH(""); /* No DBUG here */ #endif FILESORT_INFO table_sort; + TABLE_LIST *tab= table->pos_in_table_list; + Item_subselect *subselect= tab ? tab->containing_subselect() : 0; /* Don't use table->sort in filesort as it is also used by QUICK_INDEX_MERGE_SELECT. Work with a copy and put it back at the end @@ -121,7 +123,6 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length, my_b_clear(&tempfile); my_b_clear(&buffpek_pointers); buffpek=0; - sort_keys= (uchar **) NULL; error= 1; bzero((char*) ¶m,sizeof(param)); param.sort_length= sortlength(thd, sortorder, s_length, &multi_byte_charset); @@ -202,13 +203,15 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length, ulong old_memavl; ulong keys= memavl/(param.rec_length+sizeof(char*)); param.keys=(uint) min(records+1, keys); - if ((sort_keys= (uchar **) make_char_array(param.keys, param.rec_length, - MYF(0)))) + if (table_sort.sort_keys || + (table_sort.sort_keys= (uchar **) make_char_array(param.keys, param.rec_length, + MYF(0)))) break; old_memavl=memavl; if ((memavl=memavl/4*3) < min_sort_memory && old_memavl > min_sort_memory) memavl= min_sort_memory; } + sort_keys= table_sort.sort_keys; if (memavl < min_sort_memory) { my_error(ER_OUTOFMEMORY,MYF(ME_ERROR+ME_WAITTANG), @@ -235,8 +238,12 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length, } else { - if (!(buffpek=read_buffpek_from_file(&buffpek_pointers, maxbuffer))) + if (!table_sort.buffpek && table_sort.buffpek_len < maxbuffer && + !(table_sort.buffpek= + (byte *) read_buffpek_from_file(&buffpek_pointers, maxbuffer))) goto err; + buffpek= (BUFFPEK *) table_sort.buffpek; + table_sort.buffpek_len= maxbuffer; close_cached_file(&buffpek_pointers); /* Open cached file if it isn't open */ if (! my_b_inited(outfile) && @@ -269,8 +276,14 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length, err: if (param.tmp_buffer) x_free(param.tmp_buffer); - x_free((gptr) sort_keys); - x_free((gptr) buffpek); + if (!subselect || !subselect->is_uncacheable()) + { + x_free((gptr) sort_keys); + table_sort.sort_keys= 0; + x_free((gptr) buffpek); + table_sort.buffpek= 0; + table_sort.buffpek_len= 0; + } close_cached_file(&tempfile); close_cached_file(&buffpek_pointers); if (my_b_inited(outfile)) @@ -301,13 +314,27 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length, } /* filesort */ -void filesort_free_buffers(TABLE *table) +void filesort_free_buffers(TABLE *table, bool full) { if (table->sort.record_pointers) { my_free((gptr) table->sort.record_pointers,MYF(0)); table->sort.record_pointers=0; } + if (full) + { + if (table->sort.sort_keys ) + { + x_free((gptr) table->sort.sort_keys); + table->sort.sort_keys= 0; + } + if (table->sort.buffpek) + { + x_free((gptr) table->sort.buffpek); + table->sort.buffpek= 0; + table->sort.buffpek_len= 0; + } + } if (table->sort.addon_buf) { my_free((char *) table->sort.addon_buf, MYF(0)); -- cgit v1.2.1 From c0f63d8564fdd1aacd001a882271dd896721d93a Mon Sep 17 00:00:00 2001 From: unknown Date: Tue, 21 Nov 2006 21:52:39 +0300 Subject: Fix typo in comment --- sql/filesort.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'sql/filesort.cc') diff --git a/sql/filesort.cc b/sql/filesort.cc index 12b17846fe4..6156d364b2b 100644 --- a/sql/filesort.cc +++ b/sql/filesort.cc @@ -974,7 +974,7 @@ uint read_to_buffer(IO_CACHE *fromfile, BUFFPEK *buffpek, Put all room used by freed buffer to use in adjacent buffer. Note, that we can't simply distribute memory evenly between all buffers, because new areas must not overlap with old ones. - SYNOPSYS + SYNOPSIS reuse_freed_buff() queue IN list of non-empty buffers, without freed buffer reuse IN empty buffer -- cgit v1.2.1