diff options
Diffstat (limited to 'src/backend/access/transam/xlogutils.c')
| -rw-r--r-- | src/backend/access/transam/xlogutils.c | 62 |
1 files changed, 32 insertions, 30 deletions
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 9abcce65483..5e60d6cccd1 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -11,7 +11,7 @@ * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/access/transam/xlogutils.c,v 1.59 2008/09/30 10:52:11 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xlogutils.c,v 1.60 2008/10/31 15:04:59 heikki Exp $ * *------------------------------------------------------------------------- */ @@ -200,6 +200,20 @@ XLogCheckInvalidPages(void) invalid_page_tab = NULL; } +/* + * XLogReadBufferExtended + * A shorthand of XLogReadBufferExtended(), for reading from the main + * fork. + * + * For historical reasons, instead of a ReadBufferMode argument, this only + * supports RBM_ZERO (init == true) and RBM_NORMAL (init == false) modes. + */ +Buffer +XLogReadBuffer(RelFileNode rnode, BlockNumber blkno, bool init) +{ + return XLogReadBufferExtended(rnode, MAIN_FORKNUM, blkno, + init ? RBM_ZERO : RBM_NORMAL); +} /* * XLogReadBuffer @@ -211,34 +225,21 @@ XLogCheckInvalidPages(void) * expect that this is only used during single-process XLOG replay, but * some subroutines such as MarkBufferDirty will complain if we don't.) * - * If "init" is true then the caller intends to rewrite the page fully - * using the info in the XLOG record. In this case we will extend the - * relation if needed to make the page exist, and we will not complain about - * the page being "new" (all zeroes); in fact, we usually will supply a - * zeroed buffer without reading the page at all, so as to avoid unnecessary - * failure if the page is present on disk but has corrupt headers. + * There's some differences in the behavior wrt. the "mode" argument, + * compared to ReadBufferExtended: * - * If "init" is false then the caller needs the page to be valid already. - * If the page doesn't exist or contains zeroes, we return InvalidBuffer. - * In this case the caller should silently skip the update on this page. - * (In this situation, we expect that the page was later dropped or truncated. - * If we don't see evidence of that later in the WAL sequence, we'll complain - * at the end of WAL replay.) - */ -Buffer -XLogReadBuffer(RelFileNode rnode, BlockNumber blkno, bool init) -{ - return XLogReadBufferWithFork(rnode, MAIN_FORKNUM, blkno, init); -} - -/* - * XLogReadBufferWithFork - * Like XLogReadBuffer, but for reading other relation forks than - * the main one. + * In RBM_NORMAL mode, if the page doesn't exist, or contains all-zeroes, we + * return InvalidBuffer. In this case the caller should silently skip the + * update on this page. (In this situation, we expect that the page was later + * dropped or truncated. If we don't see evidence of that later in the WAL + * sequence, we'll complain at the end of WAL replay.) + * + * In RBM_ZERO and RBM_ZERO_ON_ERROR modes, if the page doesn't exist, the + * relation is extended with all-zeroes pages up to the given block number. */ Buffer -XLogReadBufferWithFork(RelFileNode rnode, ForkNumber forknum, - BlockNumber blkno, bool init) +XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, + BlockNumber blkno, ReadBufferMode mode) { BlockNumber lastblock; Buffer buffer; @@ -264,12 +265,13 @@ XLogReadBufferWithFork(RelFileNode rnode, ForkNumber forknum, if (blkno < lastblock) { /* page exists in file */ - buffer = ReadBufferWithoutRelcache(rnode, false, forknum, blkno, init); + buffer = ReadBufferWithoutRelcache(rnode, false, forknum, blkno, + mode, NULL); } else { /* hm, page doesn't exist in file */ - if (!init) + if (mode == RBM_NORMAL) { log_invalid_page(rnode, forknum, blkno, false); return InvalidBuffer; @@ -283,7 +285,7 @@ XLogReadBufferWithFork(RelFileNode rnode, ForkNumber forknum, if (buffer != InvalidBuffer) ReleaseBuffer(buffer); buffer = ReadBufferWithoutRelcache(rnode, false, forknum, - P_NEW, false); + P_NEW, mode, NULL); lastblock++; } Assert(BufferGetBlockNumber(buffer) == blkno); @@ -291,7 +293,7 @@ XLogReadBufferWithFork(RelFileNode rnode, ForkNumber forknum, LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE); - if (!init) + if (mode == RBM_NORMAL) { /* check that page has been initialized */ Page page = (Page) BufferGetPage(buffer); |