diff options
Diffstat (limited to 'src/backend/access/transam/slru.c')
| -rw-r--r-- | src/backend/access/transam/slru.c | 23 |
1 files changed, 3 insertions, 20 deletions
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c index d5f999f494b..6226acc9283 100644 --- a/src/backend/access/transam/slru.c +++ b/src/backend/access/transam/slru.c @@ -41,7 +41,7 @@ * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/access/transam/slru.c,v 1.48 2010/01/02 16:57:35 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/slru.c,v 1.49 2010/02/16 22:34:43 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -59,25 +59,6 @@ #include "miscadmin.h" -/* - * Define segment size. A page is the same BLCKSZ as is used everywhere - * else in Postgres. The segment size can be chosen somewhat arbitrarily; - * we make it 32 pages by default, or 256Kb, i.e. 1M transactions for CLOG - * or 64K transactions for SUBTRANS. - * - * Note: because TransactionIds are 32 bits and wrap around at 0xFFFFFFFF, - * page numbering also wraps around at 0xFFFFFFFF/xxxx_XACTS_PER_PAGE (where - * xxxx is CLOG or SUBTRANS, respectively), and segment numbering at - * 0xFFFFFFFF/xxxx_XACTS_PER_PAGE/SLRU_PAGES_PER_SEGMENT. We need - * take no explicit notice of that fact in this module, except when comparing - * segment and page numbers in SimpleLruTruncate (see PagePrecedes()). - * - * Note: this file currently assumes that segment file names will be four - * hex digits. This sets a lower bound on the segment size (64K transactions - * for 32-bit TransactionIds). - */ -#define SLRU_PAGES_PER_SEGMENT 32 - #define SlruFileName(ctl, path, seg) \ snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->Dir, seg) @@ -183,6 +164,8 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns, shared = (SlruShared) ShmemInitStruct(name, SimpleLruShmemSize(nslots, nlsns), &found); + if (!shared) + elog(ERROR, "out of shared memory"); if (!IsUnderPostmaster) { |