Convert the arithmetic for shared memory size calculation from 'int'

to 'Size' (that is, size_t), and install overflow detection checks in it.
This allows us to remove the former arbitrary restrictions on NBuffers
etc.  It won't make any difference in a 32-bit machine, but in a 64-bit
machine you could theoretically have terabytes of shared buffers.
(How efficiently we could manage 'em remains to be seen.)  Similarly,
num_temp_buffers, work_mem, and maintenance_work_mem can be set above
2Gb on a 64-bit machine.  Original patch from Koichi Suzuki, additional
work by moi.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c
index 247a9abf591..906165638b6 100644
--- a/src/backend/storage/buffer/freelist.c
+++ b/src/backend/storage/buffer/freelist.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/buffer/freelist.c,v 1.51 2005/03/04 20:21:06 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/buffer/freelist.c,v 1.52 2005/08/20 23:26:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -208,16 +208,16 @@ StrategyHintVacuum(bool vacuum_active)
  * Note: for somewhat historical reasons, the buffer lookup hashtable size
  * is also determined here.
  */
-int
+Size
 StrategyShmemSize(void)
 {
-	int			size = 0;
+	Size		size = 0;
 
 	/* size of lookup hash table */
-	size += BufTableShmemSize(NBuffers);
+	size = add_size(size, BufTableShmemSize(NBuffers));
 
 	/* size of the shared replacement strategy control block */
-	size += MAXALIGN(sizeof(BufferStrategyControl));
+	size = add_size(size, MAXALIGN(sizeof(BufferStrategyControl)));
 
 	return size;
 }