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

include/my_bitmap.h

+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+   
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+   
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+   
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+   MA 02111-1307, USA */
+
+#ifndef _my_bitmap_h_
+#define _my_bitmap_h_
+
+#define MY_BIT_NONE ~(uint)0
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+  extern void bitmap_set_bit(uchar *bitmap, uint bitmap_size, uint bitmap_bit);
+  extern uint bitmap_set_next(uchar *bitmap, uint bitmap_size);
+  extern void bitmap_clear_bit(uchar *bitmap,uint bitmap_size,uint bitmap_bit);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif

mysys/Makefile.am

@@ -44,7 +44,7 @@ libmysys_a_SOURCES =	my_init.c my_getwd.c mf_getdate.c\
 			my_quick.c my_lockmem.c my_static.c \
 			getopt.c getopt1.c getvar.c my_mkdir.c \
 			default.c my_compress.c checksum.c raid.cc my_net.c \
-			my_vsnprintf.c charset.c
+			my_vsnprintf.c charset.c my_bitmap.c
 EXTRA_DIST =		thr_alarm.c thr_lock.c my_pthread.c my_thr_init.c \
 			thr_mutex.c thr_rwlock.c
 libmysys_a_LIBADD =	@THREAD_LOBJECTS@

mysys/my_bitmap.c

+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+   
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+   
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+   
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+   MA 02111-1307, USA */
+
+/*
+  Handling of uchar arrays as large bitmaps.
+*/
+
+#include "mysys_priv.h"
+#include <my_bitmap.h>
+
+pthread_mutex_t LOCK_bitmap;
+
+void bitmap_set_bit(uchar *bitmap, uint bitmap_size, uint bitmap_bit) {
+  if((bitmap_bit != MY_BIT_NONE) && (bitmap_bit < bitmap_size*8)) {
+    pthread_mutex_lock(&LOCK_bitmap);
+    bitmap[bitmap_bit / 8] |= (1 << bitmap_bit % 8);
+    pthread_mutex_unlock(&LOCK_bitmap);
+  };
+};
+
+uint bitmap_set_next(uchar *bitmap, uint bitmap_size) {
+  uint bit_found = MY_BIT_NONE;
+  int i, b;
+
+  pthread_mutex_lock(&LOCK_bitmap);
+  for(i=0; (i<bitmap_size) && (bit_found==MY_BIT_NONE); i++) {
+    if(bitmap[i] == 0xff) continue;
+    for(b=0; (b<8) && (bit_found==MY_BIT_NONE); b++)
+      if((bitmap[i] & 1<<b) == 0) {
+        bit_found = (i*8)+b;
+        bitmap[i] |= 1<<b;
+      };
+  };
+  pthread_mutex_unlock(&LOCK_bitmap);
+
+  return bit_found;
+};
+
+void bitmap_clear_bit(uchar *bitmap, uint bitmap_size, uint bitmap_bit) {
+  if((bitmap_bit != MY_BIT_NONE) && (bitmap_bit < bitmap_size*8)) {
+    pthread_mutex_lock(&LOCK_bitmap);
+    bitmap[bitmap_bit / 8] &= ~(1 << bitmap_bit % 8);
+    pthread_mutex_unlock(&LOCK_bitmap);
+  };
+};
+

mysys/my_init.c

@@ -48,6 +48,7 @@ static my_bool win32_init_tcp_ip();
 static my_bool my_init_done=0;
 
 
+
 static ulong atoi_octal(const char *str)
 {
   long int tmp;
@@ -76,6 +77,7 @@ void my_init(void)
 #ifndef __WIN__
   sigfillset(&my_signals);		/* signals blocked by mf_brkhant */
 #endif
+  pthread_mutex_init(&LOCK_bitmap, NULL);
 #endif
   {
     DBUG_ENTER("my_init");
@@ -127,7 +129,12 @@ void my_end(int infoflag)
 #ifdef HAVE_GETRUSAGE
     struct rusage rus;
     if (!getrusage(RUSAGE_SELF, &rus))
-      fprintf(info_file,"\nUser time %.2f, System time %.2f\nMaximum resident set size %ld, Integral resident set size %ld\nNon physical pagefaults %ld, Physical pagefaults %ld, Swaps %ld\nBlocks in %ld out %ld, Messages in %ld out %ld, Signals %ld\nVouluntary context switches %ld, Invouluntary context switches %ld\n",
+      fprintf(info_file,"\n\
+User time %.2f, System time %.2f\n\
+Maximum resident set size %ld, Integral resident set size %ld\n\
+Non-physical pagefaults %ld, Physical pagefaults %ld, Swaps %ld\n\
+Blocks in %ld out %ld, Messages in %ld out %ld, Signals %ld\n\
+Voluntary context switches %ld, Involuntary context switches %ld\n",
 	      (rus.ru_utime.tv_sec * SCALE_SEC +
 	       rus.ru_utime.tv_usec / SCALE_USEC) / 100.0,
 	      (rus.ru_stime.tv_sec * SCALE_SEC +
@@ -159,6 +166,7 @@ void my_end(int infoflag)
   pthread_mutex_destroy(&THR_LOCK_keycache);
   pthread_mutex_destroy(&THR_LOCK_malloc);
   pthread_mutex_destroy(&THR_LOCK_open);
+  pthread_mutex_destroy(&LOCK_bitmap);
   DBUG_POP();				/* Must be done before my_thread_end */
   my_thread_end();
   my_thread_global_end();

mysys/mysys_priv.h

@@ -25,6 +25,7 @@
 #ifdef THREAD
 extern pthread_mutex_t THR_LOCK_malloc,THR_LOCK_open,THR_LOCK_keycache,
   THR_LOCK_lock,THR_LOCK_isam,THR_LOCK_net,THR_LOCK_charset;
+extern pthread_mutex_t LOCK_bitmap;
 #else /* THREAD */
 #define pthread_mutex_lock(A)
 #define pthread_mutex_unlock(A)

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;

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;

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;
 

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;
 };