diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtree.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtree.c | 41 |
1 files changed, 21 insertions, 20 deletions
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index 4553aaee531..ad07b80f758 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -151,31 +151,32 @@ bthandler(PG_FUNCTION_ARGS) void btbuildempty(Relation index) { + Buffer metabuf; Page metapage; - /* Construct metapage. */ - metapage = (Page) palloc_aligned(BLCKSZ, PG_IO_ALIGN_SIZE, 0); - _bt_initmetapage(metapage, P_NONE, 0, _bt_allequalimage(index, false)); - /* - * Write the page and log it. It might seem that an immediate sync would - * be sufficient to guarantee that the file exists on disk, but recovery - * itself might remove it while replaying, for example, an - * XLOG_DBASE_CREATE* or XLOG_TBLSPC_CREATE record. Therefore, we need - * this even when wal_level=minimal. + * Initalize the metapage. + * + * Regular index build bypasses the buffer manager and uses smgr functions + * directly, with an smgrimmedsync() call at the end. That makes sense + * when the index is large, but for an empty index, it's better to use the + * buffer cache to avoid the smgrimmedsync(). */ - PageSetChecksumInplace(metapage, BTREE_METAPAGE); - smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, BTREE_METAPAGE, - metapage, true); - log_newpage(&RelationGetSmgr(index)->smgr_rlocator.locator, INIT_FORKNUM, - BTREE_METAPAGE, metapage, true); + metabuf = ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL); + Assert(BufferGetBlockNumber(metabuf) == BTREE_METAPAGE); + _bt_lockbuf(index, metabuf, BT_WRITE); - /* - * An immediate sync is required even if we xlog'd the page, because the - * write did not go through shared_buffers and therefore a concurrent - * checkpoint may have moved the redo pointer past our xlog record. - */ - smgrimmedsync(RelationGetSmgr(index), INIT_FORKNUM); + START_CRIT_SECTION(); + + metapage = BufferGetPage(metabuf); + _bt_initmetapage(metapage, P_NONE, 0, _bt_allequalimage(index, false)); + MarkBufferDirty(metabuf); + log_newpage_buffer(metabuf, true); + + END_CRIT_SECTION(); + + _bt_unlockbuf(index, metabuf); + ReleaseBuffer(metabuf); } /* |