Added --temp-pool option to mysqld. This will cause temporary files

created to use a small set of filenames, to try and avoid problems
in the Linux kernel.

1 files changed, 26 insertions, 3 deletions

diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 2d8373ec067..16d525f0ea7 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -30,6 +30,7 @@
 #include <hash.h>
 #include <ft_global.h>
 #include <assert.h>
+#include <my_bitmap.h>
 
 const char *join_type_str[]={ "UNKNOWN","system","const","eq_ref","ref",
 			      "MAYBE_REF","ALL","range","index","fulltext" };
@@ -3276,14 +3277,28 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   KEY_PART_INFO *key_part_info;
   Item_result_field **copy_func;
   MI_COLUMNDEF *recinfo;
+  uint temp_pool_slot;
+
   DBUG_ENTER("create_tmp_table");
   DBUG_PRINT("enter",("distinct: %d  save_sum_fields: %d  allow_distinct_limit: %d  group: %d",
 		      (int) distinct, (int) save_sum_fields,
 		      (int) allow_distinct_limit,test(group)));
 
   statistic_increment(created_tmp_tables, &LOCK_status);
-  sprintf(path,"%s%s%lx_%lx_%x",mysql_tmpdir,tmp_file_prefix,current_pid,
-	  thd->thread_id, thd->tmp_table++);
+
+  if(use_temp_pool) {
+    temp_pool_slot = bitmap_set_next(temp_pool, TEMP_POOL_SIZE);
+    if(temp_pool_slot != MY_BIT_NONE) // we got a slot
+      sprintf(path, "%s%s_%lx_%i", mysql_tmpdir, tmp_file_prefix, 
+              current_pid, temp_pool_slot);
+    else // if we run out of slots in the pool, fall back to old behavior
+      sprintf(path,"%s%s%lx_%lx_%x",mysql_tmpdir,tmp_file_prefix,current_pid,
+              thd->thread_id, thd->tmp_table++);
+  } else {
+    sprintf(path,"%s%s%lx_%lx_%x",mysql_tmpdir,tmp_file_prefix,current_pid,
+            thd->thread_id, thd->tmp_table++);
+  };
+
   if (group)
   {
     if (!param->quick_group)
@@ -3310,10 +3325,12 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 		       param->group_length : 0,
 		       NullS))
   {
+    bitmap_clear_bit(temp_pool, TEMP_POOL_SIZE, temp_pool_slot);
     DBUG_RETURN(NULL); /* purecov: inspected */
   }
   if (!(param->copy_field=copy=new Copy_field[field_count]))
   {
+    bitmap_clear_bit(temp_pool, TEMP_POOL_SIZE, temp_pool_slot);
     my_free((gptr) table,MYF(0)); /* purecov: inspected */
     DBUG_RETURN(NULL); /* purecov: inspected */
   }
@@ -3333,6 +3350,8 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   table->map=1;
   table->tmp_table=1;
   table->db_low_byte_first=1;			// True for HEAP and MyISAM
+  table->temp_pool_slot = temp_pool_slot;
+
 
   /* Calculate with type of fields we will need in heap table */
 
@@ -3626,7 +3645,8 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
     DBUG_RETURN(table);
 
  err:
-  free_tmp_table(thd,table);			/* purecov: inspected */
+  free_tmp_table(thd,table);                    /* purecov: inspected */
+  bitmap_clear_bit(temp_pool, TEMP_POOL_SIZE, temp_pool_slot);
   DBUG_RETURN(NULL);				/* purecov: inspected */
 }
 
@@ -3773,6 +3793,9 @@ free_tmp_table(THD *thd, TABLE *entry)
     delete *ptr;
   my_free((gptr) entry->record[0],MYF(0));
   free_io_cache(entry);
+
+  bitmap_clear_bit(temp_pool, TEMP_POOL_SIZE, entry->temp_pool_slot);
+
   my_free((gptr) entry,MYF(0));
   thd->proc_info=save_proc_info;