diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/nbtree/nbtinsert.c | 49 |
1 files changed, 29 insertions, 20 deletions
diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c index be60781fc98..85d97a970ac 100644 --- a/src/backend/access/nbtree/nbtinsert.c +++ b/src/backend/access/nbtree/nbtinsert.c @@ -1473,6 +1473,8 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, Page origpage; Page leftpage, rightpage; + PGAlignedBlock leftpage_buf, + rightpage_buf; BlockNumber origpagenumber, rightpagenumber; BTPageOpaque ropaque, @@ -1543,8 +1545,8 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, firstrightoff = _bt_findsplitloc(rel, origpage, newitemoff, newitemsz, newitem, &newitemonleft); - /* Allocate temp buffer for leftpage */ - leftpage = PageGetTempPage(origpage); + /* Use temporary buffer for leftpage */ + leftpage = leftpage_buf.data; _bt_pageinit(leftpage, BufferGetPageSize(buf)); lopaque = BTPageGetOpaque(leftpage); @@ -1707,19 +1709,23 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, /* * Acquire a new right page to split into, now that left page has a new - * high key. From here on, it's not okay to throw an error without - * zeroing rightpage first. This coding rule ensures that we won't - * confuse future VACUUM operations, which might otherwise try to re-find - * a downlink to a leftover junk page as the page undergoes deletion. + * high key. * - * It would be reasonable to start the critical section just after the new - * rightpage buffer is acquired instead; that would allow us to avoid - * leftover junk pages without bothering to zero rightpage. We do it this - * way because it avoids an unnecessary PANIC when either origpage or its - * existing sibling page are corrupt. + * To not confuse future VACUUM operations, we zero the right page and + * work on an in-memory copy of it before writing WAL, then copy its + * contents back to the actual page once we start the critical section + * work. This simplifies the split work, so as there is no need to zero + * the right page before throwing an error. */ rbuf = _bt_allocbuf(rel, heaprel); - rightpage = BufferGetPage(rbuf); + rightpage = rightpage_buf.data; + + /* + * Copy the contents of the right page into its temporary location, and + * zero the original space. + */ + memcpy(rightpage, BufferGetPage(rbuf), BLCKSZ); + memset(BufferGetPage(rbuf), 0, BLCKSZ); rightpagenumber = BufferGetBlockNumber(rbuf); /* rightpage was initialized by _bt_allocbuf */ ropaque = BTPageGetOpaque(rightpage); @@ -1768,7 +1774,6 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, if (PageAddItem(rightpage, (Item) righthighkey, itemsz, afterrightoff, false, false) == InvalidOffsetNumber) { - memset(rightpage, 0, BufferGetPageSize(rbuf)); elog(ERROR, "failed to add high key to the right sibling" " while splitting block %u of index \"%s\"", origpagenumber, RelationGetRelationName(rel)); @@ -1816,7 +1821,6 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, if (!_bt_pgaddtup(leftpage, newitemsz, newitem, afterleftoff, false)) { - memset(rightpage, 0, BufferGetPageSize(rbuf)); elog(ERROR, "failed to add new item to the left sibling" " while splitting block %u of index \"%s\"", origpagenumber, RelationGetRelationName(rel)); @@ -1829,7 +1833,6 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, if (!_bt_pgaddtup(rightpage, newitemsz, newitem, afterrightoff, afterrightoff == minusinfoff)) { - memset(rightpage, 0, BufferGetPageSize(rbuf)); elog(ERROR, "failed to add new item to the right sibling" " while splitting block %u of index \"%s\"", origpagenumber, RelationGetRelationName(rel)); @@ -1843,7 +1846,6 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, { if (!_bt_pgaddtup(leftpage, itemsz, dataitem, afterleftoff, false)) { - memset(rightpage, 0, BufferGetPageSize(rbuf)); elog(ERROR, "failed to add old item to the left sibling" " while splitting block %u of index \"%s\"", origpagenumber, RelationGetRelationName(rel)); @@ -1855,7 +1857,6 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, if (!_bt_pgaddtup(rightpage, itemsz, dataitem, afterrightoff, afterrightoff == minusinfoff)) { - memset(rightpage, 0, BufferGetPageSize(rbuf)); elog(ERROR, "failed to add old item to the right sibling" " while splitting block %u of index \"%s\"", origpagenumber, RelationGetRelationName(rel)); @@ -1876,7 +1877,6 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, if (!_bt_pgaddtup(rightpage, newitemsz, newitem, afterrightoff, afterrightoff == minusinfoff)) { - memset(rightpage, 0, BufferGetPageSize(rbuf)); elog(ERROR, "failed to add new item to the right sibling" " while splitting block %u of index \"%s\"", origpagenumber, RelationGetRelationName(rel)); @@ -1896,7 +1896,6 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, sopaque = BTPageGetOpaque(spage); if (sopaque->btpo_prev != origpagenumber) { - memset(rightpage, 0, BufferGetPageSize(rbuf)); ereport(ERROR, (errcode(ERRCODE_INDEX_CORRUPTED), errmsg_internal("right sibling's left-link doesn't match: " @@ -1939,9 +1938,19 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf, * original. We need to do this before writing the WAL record, so that * XLogInsert can WAL log an image of the page if necessary. */ - PageRestoreTempPage(leftpage, origpage); + memcpy(origpage, leftpage, BLCKSZ); /* leftpage, lopaque must not be used below here */ + /* + * Move the contents of the right page from its temporary location to the + * destination buffer, before writing the WAL record. Unlike the left + * page, the right page and its opaque area are still needed to complete + * the update of the page, so reinitialize them. + */ + rightpage = BufferGetPage(rbuf); + memcpy(rightpage, rightpage_buf.data, BLCKSZ); + ropaque = BTPageGetOpaque(rightpage); + MarkBufferDirty(buf); MarkBufferDirty(rbuf); |