diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtxlog.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtxlog.c | 52 |
1 files changed, 28 insertions, 24 deletions
diff --git a/src/backend/access/nbtree/nbtxlog.c b/src/backend/access/nbtree/nbtxlog.c index f5320fb1039..07416d599b5 100644 --- a/src/backend/access/nbtree/nbtxlog.c +++ b/src/backend/access/nbtree/nbtxlog.c @@ -8,7 +8,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.61 2010/02/13 00:59:58 sriggs Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.62 2010/02/26 02:00:34 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -473,10 +473,10 @@ btree_xlog_vacuum(XLogRecPtr lsn, XLogRecord *record) xlrec = (xl_btree_vacuum *) XLogRecGetData(record); /* - * If queries might be active then we need to ensure every block is unpinned - * between the lastBlockVacuumed and the current block, if there are any. - * This ensures that every block in the index is touched during VACUUM as - * required to ensure scans work correctly. + * If queries might be active then we need to ensure every block is + * unpinned between the lastBlockVacuumed and the current block, if there + * are any. This ensures that every block in the index is touched during + * VACUUM as required to ensure scans work correctly. */ if (standbyState == STANDBY_SNAPSHOT_READY && (xlrec->lastBlockVacuumed + 1) != xlrec->block) @@ -486,10 +486,10 @@ btree_xlog_vacuum(XLogRecPtr lsn, XLogRecord *record) for (; blkno < xlrec->block; blkno++) { /* - * XXX we don't actually need to read the block, we - * just need to confirm it is unpinned. If we had a special call - * into the buffer manager we could optimise this so that - * if the block is not in shared_buffers we confirm it as unpinned. + * XXX we don't actually need to read the block, we just need to + * confirm it is unpinned. If we had a special call into the + * buffer manager we could optimise this so that if the block is + * not in shared_buffers we confirm it as unpinned. * * Another simple optimization would be to check if there's any * backends running; if not, we could just skip this. @@ -505,9 +505,9 @@ btree_xlog_vacuum(XLogRecPtr lsn, XLogRecord *record) /* * If the block was restored from a full page image, nothing more to do. - * The RestoreBkpBlocks() call already pinned and took cleanup lock on - * it. XXX: Perhaps we should call RestoreBkpBlocks() *after* the loop - * above, to make the disk access more sequential. + * The RestoreBkpBlocks() call already pinned and took cleanup lock on it. + * XXX: Perhaps we should call RestoreBkpBlocks() *after* the loop above, + * to make the disk access more sequential. */ if (record->xl_info & XLR_BKP_BLOCK_1) return; @@ -567,8 +567,8 @@ btree_xlog_delete(XLogRecPtr lsn, XLogRecord *record) xlrec = (xl_btree_delete *) XLogRecGetData(record); /* - * We don't need to take a cleanup lock to apply these changes. - * See nbtree/README for details. + * We don't need to take a cleanup lock to apply these changes. See + * nbtree/README for details. */ buffer = XLogReadBuffer(xlrec->node, xlrec->block, false); if (!BufferIsValid(buffer)) @@ -819,13 +819,15 @@ btree_redo(XLogRecPtr lsn, XLogRecord *record) switch (info) { case XLOG_BTREE_DELETE: + /* - * Btree delete records can conflict with standby queries. You might - * think that vacuum records would conflict as well, but we've handled - * that already. XLOG_HEAP2_CLEANUP_INFO records provide the highest xid - * cleaned by the vacuum of the heap and so we can resolve any conflicts - * just once when that arrives. After that any we know that no conflicts - * exist from individual btree vacuum records on that index. + * Btree delete records can conflict with standby queries. You + * might think that vacuum records would conflict as well, but + * we've handled that already. XLOG_HEAP2_CLEANUP_INFO records + * provide the highest xid cleaned by the vacuum of the heap + * and so we can resolve any conflicts just once when that + * arrives. After that any we know that no conflicts exist + * from individual btree vacuum records on that index. */ { xl_btree_delete *xlrec = (xl_btree_delete *) XLogRecGetData(record); @@ -842,9 +844,11 @@ btree_redo(XLogRecPtr lsn, XLogRecord *record) break; case XLOG_BTREE_REUSE_PAGE: + /* - * Btree reuse page records exist to provide a conflict point when we - * reuse pages in the index via the FSM. That's all it does though. + * Btree reuse page records exist to provide a conflict point + * when we reuse pages in the index via the FSM. That's all it + * does though. */ { xl_btree_reuse_page *xlrec = (xl_btree_reuse_page *) XLogRecGetData(record); @@ -859,8 +863,8 @@ btree_redo(XLogRecPtr lsn, XLogRecord *record) } /* - * Vacuum needs to pin and take cleanup lock on every leaf page, - * a regular exclusive lock is enough for all other purposes. + * Vacuum needs to pin and take cleanup lock on every leaf page, a regular + * exclusive lock is enough for all other purposes. */ RestoreBkpBlocks(lsn, record, (info == XLOG_BTREE_VACUUM)); |