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.


mysys/Makefile.am:
  Added my_bitmap.c
mysys/my_init.c:
  my_bitmap code added
mysys/mysys_priv.h:
  my_bitmap
sql/mysql_priv.h:
  temp pool stuff.
sql/mysqld.cc:
  --temp-pool option added
sql/sql_select.cc:
  temp pool stuff
sql/table.h:
  temp pool

4 files changed, 44 insertions, 5 deletions

diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index d3f208aa6de..4c83d70abf1 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -73,6 +73,7 @@ void kill_one_thread(THD *thd, ulong id);
 #ifndef MYSQLD_NET_RETRY_COUNT
 #define MYSQLD_NET_RETRY_COUNT  10	// Abort read after this many int.
 #endif
+#define TEMP_POOL_SIZE          128
 /* The following parameters is to decide when to use an extra cache to
    optimise seeks when reading a big table in sorted order */
 #define MIN_FILE_LENGTH_TO_USE_ROW_CACHE (16L*1024*1024)
@@ -507,7 +508,8 @@ extern ulong ha_read_count, ha_write_count, ha_delete_count, ha_update_count,
 	     ha_read_key_count, ha_read_next_count, ha_read_prev_count,
 	     ha_read_first_count, ha_read_last_count,
   	     ha_read_rnd_count, ha_read_rnd_next_count;
-
+extern uchar temp_pool[TEMP_POOL_SIZE];
+extern bool use_temp_pool;
 extern char f_fyllchar;
 extern uchar *days_in_month;
 extern DATE_FORMAT dayord;
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 62ee256b9da..b8a502ad2a4 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -287,6 +287,9 @@ I_List<THD> threads,thread_cache;
 time_t start_time;
 
 
+uchar temp_pool[TEMP_POOL_SIZE];
+bool use_temp_pool;
+
 pthread_key(MEM_ROOT*,THR_MALLOC);
 pthread_key(THD*, THR_THD);
 pthread_key(NET*, THR_NET);
@@ -1498,6 +1501,9 @@ int main(int argc, char **argv)
   if (!mysql_tmpdir || !mysql_tmpdir[0])
     mysql_tmpdir=(char*) P_tmpdir;		/* purecov: inspected */
 
+  bzero(temp_pool, TEMP_POOL_SIZE);
+  use_temp_pool = 0;
+
   set_options();
 #ifdef __WIN__
   /* service parameters can be overwritten by options */
@@ -2370,7 +2376,8 @@ enum options {
 	       OPT_INNOBASE_LOG_GROUP_HOME_DIR,
 	       OPT_INNOBASE_LOG_ARCH_DIR, OPT_INNOBASE_LOG_ARCHIVE,
 	       OPT_INNOBASE_FLUSH_LOG_AT_TRX_COMMIT, OPT_SAFE_SHOW_DB,
-	       OPT_GEMINI_SKIP
+	       OPT_GEMINI_SKIP,
+               OPT_TEMP_POOL
 };
 
 static struct option long_options[] = {
@@ -2501,6 +2508,7 @@ static struct option long_options[] = {
 #ifdef __WIN__
   {"standalone",            no_argument,       0, (int) OPT_STANDALONE},
 #endif
+  {"temp-pool",             no_argument,       0, (int) OPT_TEMP_POOL},
   {"tmpdir",                required_argument, 0, 't'},
   {"use-locking",           no_argument,       0, (int) OPT_USE_LOCKING},
 #ifdef USE_SYMDIR
@@ -2874,6 +2882,7 @@ static void usage(void)
 			Don't give threads different priorities.\n\
   --socket=...		Socket file to use for connection\n\
   -t, --tmpdir=path	Path for temporary files\n\
+  --temp-pool           Use a pool of temporary files\n\
   -u, --user=user_name	Run mysqld daemon as user\n\
   -V, --version		output version information and exit");
 #ifdef __WIN__
@@ -3049,6 +3058,9 @@ static void get_options(int argc,char **argv)
     case 't':
       mysql_tmpdir=optarg;
       break;
+    case OPT_TEMP_POOL:
+      use_temp_pool=1;
+      break;
     case 'u':
       mysqld_user=optarg;
       break;
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;
 
diff --git a/sql/table.h b/sql/table.h
index 8121271b479..c709be6a08c 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -119,6 +119,8 @@ struct st_table {
   key_part_map  const_key_parts[MAX_KEY];
   ulong		query_id;
 
+  uint          temp_pool_slot;
+
   THD		*in_use;			/* Which thread uses this */
   struct st_table *next,*prev;
 };