greenplumn nbtxlog 源码
greenplumn nbtxlog 代码
文件路径：/src/backend/access/nbtree/nbtxlog.c
/*-------------------------------------------------------------------------
*
* nbtxlog.c
* WAL replay logic for btrees.
*
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/access/nbtree/nbtxlog.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/bufmask.h"
#include "access/nbtree.h"
#include "access/nbtxlog.h"
#include "access/transam.h"
#include "access/xlog.h"
#include "access/xlogutils.h"
#include "storage/procarray.h"
#include "miscadmin.h"
#include "access/bufmask.h"
/*
* _bt_restore_page -- re-enter all the index tuples on a page
*
* The page is freshly init'd, and *from (length len) is a copy of what
* had been its upper part (pd_upper to pd_special). We assume that the
* tuples had been added to the page in item-number order, and therefore
* the one with highest item number appears first (lowest on the page).
*/
static void
_bt_restore_page(Page page, char *from, int len)
{
IndexTupleData itupdata;
Size itemsz;
char *end = from + len;
Item items[MaxIndexTuplesPerPage];
uint16 itemsizes[MaxIndexTuplesPerPage];
int i;
int nitems;
/*
* To get the items back in the original order, we add them to the page in
* reverse. To figure out where one tuple ends and another begins, we
* have to scan them in forward order first.
*/
i = 0;
while (from < end)
{
/*
* As we step through the items, 'from' won't always be properly
* aligned, so we need to use memcpy(). Further, we use Item (which
* is just a char*) here for our items array for the same reason;
* wouldn't want the compiler or anyone thinking that an item is
* aligned when it isn't.
*/
memcpy(&itupdata, from, sizeof(IndexTupleData));
itemsz = IndexTupleSize(&itupdata);
itemsz = MAXALIGN(itemsz);
items[i] = (Item) from;
itemsizes[i] = itemsz;
i++;
from += itemsz;
}
nitems = i;
for (i = nitems - 1; i >= 0; i--)
{
if (PageAddItem(page, items[i], itemsizes[i], nitems - i,
false, false) == InvalidOffsetNumber)
elog(PANIC, "_bt_restore_page: cannot add item to page");
from += itemsz;
}
}
static void
_bt_restore_meta(XLogReaderState *record, uint8 block_id)
{
XLogRecPtr lsn = record->EndRecPtr;
Buffer metabuf;
Page metapg;
BTMetaPageData *md;
BTPageOpaque pageop;
xl_btree_metadata *xlrec;
char *ptr;
Size len;
metabuf = XLogInitBufferForRedo(record, block_id);
ptr = XLogRecGetBlockData(record, block_id, &len);
Assert(len == sizeof(xl_btree_metadata));
Assert(BufferGetBlockNumber(metabuf) == BTREE_METAPAGE);
xlrec = (xl_btree_metadata *) ptr;
metapg = BufferGetPage(metabuf);
_bt_pageinit(metapg, BufferGetPageSize(metabuf));
md = BTPageGetMeta(metapg);
md->btm_magic = BTREE_MAGIC;
md->btm_version = xlrec->version;
md->btm_root = xlrec->root;
md->btm_level = xlrec->level;
md->btm_fastroot = xlrec->fastroot;
md->btm_fastlevel = xlrec->fastlevel;
md->btm_oldest_btpo_xact = xlrec->oldest_btpo_xact;
md->btm_last_cleanup_num_heap_tuples = xlrec->last_cleanup_num_heap_tuples;
pageop = (BTPageOpaque) PageGetSpecialPointer(metapg);
pageop->btpo_flags = BTP_META;
/*
* Set pd_lower just past the end of the metadata. This is essential,
* because without doing so, metadata will be lost if xlog.c compresses
* the page.
*/
((PageHeader) metapg)->pd_lower =
((char *) md + sizeof(BTMetaPageData)) - (char *) metapg;
PageSetLSN(metapg, lsn);
MarkBufferDirty(metabuf);
UnlockReleaseBuffer(metabuf);
}
/*
* _bt_clear_incomplete_split -- clear INCOMPLETE_SPLIT flag on a page
*
* This is a common subroutine of the redo functions of all the WAL record
* types that can insert a downlink: insert, split, and newroot.
*/
static void
_bt_clear_incomplete_split(XLogReaderState *record, uint8 block_id)
{
XLogRecPtr lsn = record->EndRecPtr;
Buffer buf;
if (XLogReadBufferForRedo(record, block_id, &buf) == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buf);
BTPageOpaque pageop = (BTPageOpaque) PageGetSpecialPointer(page);
Assert(P_INCOMPLETE_SPLIT(pageop));
pageop->btpo_flags &= ~BTP_INCOMPLETE_SPLIT;
PageSetLSN(page, lsn);
MarkBufferDirty(buf);
}
if (BufferIsValid(buf))
UnlockReleaseBuffer(buf);
}
static void
btree_xlog_insert(bool isleaf, bool ismeta, XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
xl_btree_insert *xlrec = (xl_btree_insert *) XLogRecGetData(record);
Buffer buffer;
Page page;
/*
* Insertion to an internal page finishes an incomplete split at the child
* level. Clear the incomplete-split flag in the child. Note: during
* normal operation, the child and parent pages are locked at the same
* time, so that clearing the flag and inserting the downlink appear
* atomic to other backends. We don't bother with that during replay,
* because readers don't care about the incomplete-split flag and there
* cannot be updates happening.
*/
if (!isleaf)
_bt_clear_incomplete_split(record, 1);
if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
{
Size datalen;
char *datapos = XLogRecGetBlockData(record, 0, &datalen);
page = BufferGetPage(buffer);
if (PageAddItem(page, (Item) datapos, datalen, xlrec->offnum,
false, false) == InvalidOffsetNumber)
elog(PANIC, "btree_xlog_insert: failed to add item");
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
/*
* Note: in normal operation, we'd update the metapage while still holding
* lock on the page we inserted into. But during replay it's not
* necessary to hold that lock, since no other index updates can be
* happening concurrently, and readers will cope fine with following an
* obsolete link from the metapage.
*/
if (ismeta)
_bt_restore_meta(record, 2);
}
static void
btree_xlog_split(bool onleft, XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
xl_btree_split *xlrec = (xl_btree_split *) XLogRecGetData(record);
bool isleaf = (xlrec->level == 0);
Buffer lbuf;
Buffer rbuf;
Page rpage;
BTPageOpaque ropaque;
char *datapos;
Size datalen;
BlockNumber leftsib;
BlockNumber rightsib;
BlockNumber rnext;
XLogRecGetBlockTag(record, 0, NULL, NULL, &leftsib);
XLogRecGetBlockTag(record, 1, NULL, NULL, &rightsib);
if (!XLogRecGetBlockTag(record, 2, NULL, NULL, &rnext))
rnext = P_NONE;
/*
* Clear the incomplete split flag on the left sibling of the child page
* this is a downlink for. (Like in btree_xlog_insert, this can be done
* before locking the other pages)
*/
if (!isleaf)
_bt_clear_incomplete_split(record, 3);
/* Reconstruct right (new) sibling page from scratch */
rbuf = XLogInitBufferForRedo(record, 1);
datapos = XLogRecGetBlockData(record, 1, &datalen);
rpage = (Page) BufferGetPage(rbuf);
_bt_pageinit(rpage, BufferGetPageSize(rbuf));
ropaque = (BTPageOpaque) PageGetSpecialPointer(rpage);
ropaque->btpo_prev = leftsib;
ropaque->btpo_next = rnext;
ropaque->btpo.level = xlrec->level;
ropaque->btpo_flags = isleaf ? BTP_LEAF : 0;
ropaque->btpo_cycleid = 0;
_bt_restore_page(rpage, datapos, datalen);
PageSetLSN(rpage, lsn);
MarkBufferDirty(rbuf);
/* Now reconstruct left (original) sibling page */
if (XLogReadBufferForRedo(record, 0, &lbuf) == BLK_NEEDS_REDO)
{
/*
* To retain the same physical order of the tuples that they had, we
* initialize a temporary empty page for the left page and add all the
* items to that in item number order. This mirrors how _bt_split()
* works. Retaining the same physical order makes WAL consistency
* checking possible. See also _bt_restore_page(), which does the
* same for the right page.
*/
Page lpage = (Page) BufferGetPage(lbuf);
BTPageOpaque lopaque = (BTPageOpaque) PageGetSpecialPointer(lpage);
OffsetNumber off;
IndexTuple newitem = NULL,
left_hikey = NULL;
Size newitemsz = 0,
left_hikeysz = 0;
Page newlpage;
OffsetNumber leftoff;
datapos = XLogRecGetBlockData(record, 0, &datalen);
if (onleft)
{
newitem = (IndexTuple) datapos;
newitemsz = MAXALIGN(IndexTupleSize(newitem));
datapos += newitemsz;
datalen -= newitemsz;
}
/* Extract left hikey and its size (assuming 16-bit alignment) */
left_hikey = (IndexTuple) datapos;
left_hikeysz = MAXALIGN(IndexTupleSize(left_hikey));
datapos += left_hikeysz;
datalen -= left_hikeysz;
Assert(datalen == 0);
newlpage = PageGetTempPageCopySpecial(lpage);
/* Set high key */
leftoff = P_HIKEY;
if (PageAddItem(newlpage, (Item) left_hikey, left_hikeysz,
P_HIKEY, false, false) == InvalidOffsetNumber)
elog(PANIC, "failed to add high key to left page after split");
leftoff = OffsetNumberNext(leftoff);
for (off = P_FIRSTDATAKEY(lopaque); off < xlrec->firstright; off++)
{
ItemId itemid;
Size itemsz;
IndexTuple item;
/* add the new item if it was inserted on left page */
if (onleft && off == xlrec->newitemoff)
{
if (PageAddItem(newlpage, (Item) newitem, newitemsz, leftoff,
false, false) == InvalidOffsetNumber)
elog(ERROR, "failed to add new item to left page after split");
leftoff = OffsetNumberNext(leftoff);
}
itemid = PageGetItemId(lpage, off);
itemsz = ItemIdGetLength(itemid);
item = (IndexTuple) PageGetItem(lpage, itemid);
if (PageAddItem(newlpage, (Item) item, itemsz, leftoff,
false, false) == InvalidOffsetNumber)
elog(ERROR, "failed to add old item to left page after split");
leftoff = OffsetNumberNext(leftoff);
}
/* cope with possibility that newitem goes at the end */
if (onleft && off == xlrec->newitemoff)
{
if (PageAddItem(newlpage, (Item) newitem, newitemsz, leftoff,
false, false) == InvalidOffsetNumber)
elog(ERROR, "failed to add new item to left page after split");
leftoff = OffsetNumberNext(leftoff);
}
PageRestoreTempPage(newlpage, lpage);
/* Fix opaque fields */
lopaque->btpo_flags = BTP_INCOMPLETE_SPLIT;
if (isleaf)
lopaque->btpo_flags |= BTP_LEAF;
lopaque->btpo_next = rightsib;
lopaque->btpo_cycleid = 0;
PageSetLSN(lpage, lsn);
MarkBufferDirty(lbuf);
}
/*
* We no longer need the buffers. They must be released together, so that
* readers cannot observe two inconsistent halves.
*/
if (BufferIsValid(lbuf))
UnlockReleaseBuffer(lbuf);
UnlockReleaseBuffer(rbuf);
/*
* Fix left-link of the page to the right of the new right sibling.
*
* Note: in normal operation, we do this while still holding lock on the
* two split pages. However, that's not necessary for correctness in WAL
* replay, because no other index update can be in progress, and readers
* will cope properly when following an obsolete left-link.
*/
if (rnext != P_NONE)
{
Buffer buffer;
if (XLogReadBufferForRedo(record, 2, &buffer) == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
BTPageOpaque pageop = (BTPageOpaque) PageGetSpecialPointer(page);
pageop->btpo_prev = rightsib;
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
}
}
static void
btree_xlog_vacuum(XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
Buffer buffer;
Page page;
BTPageOpaque opaque;
#ifdef UNUSED
xl_btree_vacuum *xlrec = (xl_btree_vacuum *) XLogRecGetData(record);
/*
* This section of code is thought to be no longer needed, after analysis
* of the calling paths. It is retained to allow the code to be reinstated
* if a flaw is revealed in that thinking.
*
* If we are running non-MVCC scans using this index we need to do some
* additional work to ensure correctness, which is known as a "pin scan"
* described in more detail in next paragraphs. We used to do the extra
* work in all cases, whereas we now avoid that work in most cases. If
* lastBlockVacuumed is set to InvalidBlockNumber then we skip the
* additional work required for the pin scan.
*
* Avoiding this extra work is important since it requires us to touch
* every page in the index, so is an O(N) operation. Worse, it is an
* operation performed in the foreground during redo, so it delays
* replication directly.
*
* If queries might be active then we need to ensure every leaf page is
* unpinned between the lastBlockVacuumed and the current block, if there
* are any. This prevents replay of the VACUUM from reaching the stage of
* removing heap tuples while there could still be indexscans "in flight"
* to those particular tuples for those scans which could be confused by
* finding new tuples at the old TID locations (see nbtree/README).
*
* It might be worth checking if there are actually any backends running;
* if not, we could just skip this.
*
* Since VACUUM can visit leaf pages out-of-order, it might issue records
* with lastBlockVacuumed >= block; that's not an error, it just means
* nothing to do now.
*
* Note: since we touch all pages in the range, we will lock non-leaf
* pages, and also any empty (all-zero) pages that may be in the index. It
* doesn't seem worth the complexity to avoid that. But it's important
* that HotStandbyActiveInReplay() will not return true if the database
* isn't yet consistent; so we need not fear reading still-corrupt blocks
* here during crash recovery.
*/
if (HotStandbyActiveInReplay() && BlockNumberIsValid(xlrec->lastBlockVacuumed))
{
RelFileNode thisrnode;
BlockNumber thisblkno;
BlockNumber blkno;
XLogRecGetBlockTag(record, 0, &thisrnode, NULL, &thisblkno);
for (blkno = xlrec->lastBlockVacuumed + 1; blkno < thisblkno; blkno++)
{
/*
* We use RBM_NORMAL_NO_LOG mode because it's not an error
* condition to see all-zero pages. The original btvacuumpage
* scan would have skipped over all-zero pages, noting them in FSM
* but not bothering to initialize them just yet; so we mustn't
* throw an error here. (We could skip acquiring the cleanup lock
* if PageIsNew, but it's probably not worth the cycles to test.)
*
* 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. Optimizing
* this is now moot, since in most cases we avoid the scan.
*/
buffer = XLogReadBufferExtended(thisrnode, MAIN_FORKNUM, blkno,
RBM_NORMAL_NO_LOG);
if (BufferIsValid(buffer))
{
LockBufferForCleanup(buffer);
UnlockReleaseBuffer(buffer);
}
}
}
#endif
/*
* Like in btvacuumpage(), we need to take a cleanup lock on every leaf
* page. See nbtree/README for details.
*/
if (XLogReadBufferForRedoExtended(record, 0, RBM_NORMAL, true, &buffer)
== BLK_NEEDS_REDO)
{
char *ptr;
Size len;
ptr = XLogRecGetBlockData(record, 0, &len);
page = (Page) BufferGetPage(buffer);
if (len > 0)
{
OffsetNumber *unused;
OffsetNumber *unend;
unused = (OffsetNumber *) ptr;
unend = (OffsetNumber *) ((char *) ptr + len);
if ((unend - unused) > 0)
PageIndexMultiDelete(page, unused, unend - unused);
}
/*
* Mark the page as not containing any LP_DEAD items --- see comments
* in _bt_delitems_vacuum().
*/
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
opaque->btpo_flags &= ~BTP_HAS_GARBAGE;
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
}
static void
btree_xlog_delete(XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
xl_btree_delete *xlrec = (xl_btree_delete *) XLogRecGetData(record);
Buffer buffer;
Page page;
BTPageOpaque opaque;
/*
* If we have any conflict processing to do, it must happen before we
* update the page.
*
* 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 we know that no conflicts
* exist from individual btree vacuum records on that index.
*/
if (InHotStandby)
{
RelFileNode rnode;
XLogRecGetBlockTag(record, 0, &rnode, NULL, NULL);
ResolveRecoveryConflictWithSnapshot(xlrec->latestRemovedXid, rnode);
}
/*
* We don't need to take a cleanup lock to apply these changes. See
* nbtree/README for details.
*/
if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
{
page = (Page) BufferGetPage(buffer);
if (XLogRecGetDataLen(record) > SizeOfBtreeDelete)
{
OffsetNumber *unused;
unused = (OffsetNumber *) ((char *) xlrec + SizeOfBtreeDelete);
PageIndexMultiDelete(page, unused, xlrec->nitems);
}
/*
* Mark the page as not containing any LP_DEAD items --- see comments
* in _bt_delitems_delete().
*/
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
opaque->btpo_flags &= ~BTP_HAS_GARBAGE;
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
}
static void
btree_xlog_mark_page_halfdead(uint8 info, XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
xl_btree_mark_page_halfdead *xlrec = (xl_btree_mark_page_halfdead *) XLogRecGetData(record);
Buffer buffer;
Page page;
BTPageOpaque pageop;
IndexTupleData trunctuple;
/*
* In normal operation, we would lock all the pages this WAL record
* touches before changing any of them. In WAL replay, it should be okay
* to lock just one page at a time, since no concurrent index updates can
* be happening, and readers should not care whether they arrive at the
* target page or not (since it's surely empty).
*/
/* parent page */
if (XLogReadBufferForRedo(record, 1, &buffer) == BLK_NEEDS_REDO)
{
OffsetNumber poffset;
ItemId itemid;
IndexTuple itup;
OffsetNumber nextoffset;
BlockNumber rightsib;
page = (Page) BufferGetPage(buffer);
pageop = (BTPageOpaque) PageGetSpecialPointer(page);
poffset = xlrec->poffset;
nextoffset = OffsetNumberNext(poffset);
itemid = PageGetItemId(page, nextoffset);
itup = (IndexTuple) PageGetItem(page, itemid);
rightsib = BTreeInnerTupleGetDownLink(itup);
itemid = PageGetItemId(page, poffset);
itup = (IndexTuple) PageGetItem(page, itemid);
BTreeInnerTupleSetDownLink(itup, rightsib);
nextoffset = OffsetNumberNext(poffset);
PageIndexTupleDelete(page, nextoffset);
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
/* Rewrite the leaf page as a halfdead page */
buffer = XLogInitBufferForRedo(record, 0);
page = (Page) BufferGetPage(buffer);
_bt_pageinit(page, BufferGetPageSize(buffer));
pageop = (BTPageOpaque) PageGetSpecialPointer(page);
pageop->btpo_prev = xlrec->leftblk;
pageop->btpo_next = xlrec->rightblk;
pageop->btpo.level = 0;
pageop->btpo_flags = BTP_HALF_DEAD | BTP_LEAF;
pageop->btpo_cycleid = 0;
/*
* Construct a dummy hikey item that points to the next parent to be
* deleted (if any).
*/
MemSet(&trunctuple, 0, sizeof(IndexTupleData));
trunctuple.t_info = sizeof(IndexTupleData);
BTreeTupleSetTopParent(&trunctuple, xlrec->topparent);
if (PageAddItem(page, (Item) &trunctuple, sizeof(IndexTupleData), P_HIKEY,
false, false) == InvalidOffsetNumber)
elog(ERROR, "could not add dummy high key to half-dead page");
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
static void
btree_xlog_unlink_page(uint8 info, XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
xl_btree_unlink_page *xlrec = (xl_btree_unlink_page *) XLogRecGetData(record);
BlockNumber leftsib;
BlockNumber rightsib;
Buffer buffer;
Page page;
BTPageOpaque pageop;
leftsib = xlrec->leftsib;
rightsib = xlrec->rightsib;
/*
* In normal operation, we would lock all the pages this WAL record
* touches before changing any of them. In WAL replay, it should be okay
* to lock just one page at a time, since no concurrent index updates can
* be happening, and readers should not care whether they arrive at the
* target page or not (since it's surely empty).
*/
/* Fix left-link of right sibling */
if (XLogReadBufferForRedo(record, 2, &buffer) == BLK_NEEDS_REDO)
{
page = (Page) BufferGetPage(buffer);
pageop = (BTPageOpaque) PageGetSpecialPointer(page);
pageop->btpo_prev = leftsib;
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
/* Fix right-link of left sibling, if any */
if (leftsib != P_NONE)
{
if (XLogReadBufferForRedo(record, 1, &buffer) == BLK_NEEDS_REDO)
{
page = (Page) BufferGetPage(buffer);
pageop = (BTPageOpaque) PageGetSpecialPointer(page);
pageop->btpo_next = rightsib;
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
}
/* Rewrite target page as empty deleted page */
buffer = XLogInitBufferForRedo(record, 0);
page = (Page) BufferGetPage(buffer);
_bt_pageinit(page, BufferGetPageSize(buffer));
pageop = (BTPageOpaque) PageGetSpecialPointer(page);
pageop->btpo_prev = leftsib;
pageop->btpo_next = rightsib;
pageop->btpo.xact = xlrec->btpo_xact;
pageop->btpo_flags = BTP_DELETED;
pageop->btpo_cycleid = 0;
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
/*
* If we deleted a parent of the targeted leaf page, instead of the leaf
* itself, update the leaf to point to the next remaining child in the
* branch.
*/
if (XLogRecHasBlockRef(record, 3))
{
/*
* There is no real data on the page, so we just re-create it from
* scratch using the information from the WAL record.
*/
IndexTupleData trunctuple;
buffer = XLogInitBufferForRedo(record, 3);
page = (Page) BufferGetPage(buffer);
_bt_pageinit(page, BufferGetPageSize(buffer));
pageop = (BTPageOpaque) PageGetSpecialPointer(page);
pageop->btpo_flags = BTP_HALF_DEAD | BTP_LEAF;
pageop->btpo_prev = xlrec->leafleftsib;
pageop->btpo_next = xlrec->leafrightsib;
pageop->btpo.level = 0;
pageop->btpo_cycleid = 0;
/* Add a dummy hikey item */
MemSet(&trunctuple, 0, sizeof(IndexTupleData));
trunctuple.t_info = sizeof(IndexTupleData);
BTreeTupleSetTopParent(&trunctuple, xlrec->topparent);
if (PageAddItem(page, (Item) &trunctuple, sizeof(IndexTupleData), P_HIKEY,
false, false) == InvalidOffsetNumber)
elog(ERROR, "could not add dummy high key to half-dead page");
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
/* Update metapage if needed */
if (info == XLOG_BTREE_UNLINK_PAGE_META)
_bt_restore_meta(record, 4);
}
static void
btree_xlog_newroot(XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
xl_btree_newroot *xlrec = (xl_btree_newroot *) XLogRecGetData(record);
Buffer buffer;
Page page;
BTPageOpaque pageop;
char *ptr;
Size len;
buffer = XLogInitBufferForRedo(record, 0);
page = (Page) BufferGetPage(buffer);
_bt_pageinit(page, BufferGetPageSize(buffer));
pageop = (BTPageOpaque) PageGetSpecialPointer(page);
pageop->btpo_flags = BTP_ROOT;
pageop->btpo_prev = pageop->btpo_next = P_NONE;
pageop->btpo.level = xlrec->level;
if (xlrec->level == 0)
pageop->btpo_flags |= BTP_LEAF;
pageop->btpo_cycleid = 0;
if (xlrec->level > 0)
{
ptr = XLogRecGetBlockData(record, 0, &len);
_bt_restore_page(page, ptr, len);
/* Clear the incomplete-split flag in left child */
_bt_clear_incomplete_split(record, 1);
}
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
_bt_restore_meta(record, 2);
}
static void
btree_xlog_reuse_page(XLogReaderState *record)
{
xl_btree_reuse_page *xlrec = (xl_btree_reuse_page *) XLogRecGetData(record);
/*
* Btree reuse_page records exist to provide a conflict point when we
* reuse pages in the index via the FSM. That's all they do though.
*
* latestRemovedXid was the page's btpo.xact. The btpo.xact <
* RecentGlobalXmin test in _bt_page_recyclable() conceptually mirrors the
* pgxact->xmin > limitXmin test in GetConflictingVirtualXIDs().
* Consequently, one XID value achieves the same exclusion effect on
* master and standby.
*/
if (InHotStandby)
{
ResolveRecoveryConflictWithSnapshot(xlrec->latestRemovedXid,
xlrec->node);
}
}
void
btree_redo(XLogReaderState *record)
{
uint8 info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
switch (info)
{
case XLOG_BTREE_INSERT_LEAF:
btree_xlog_insert(true, false, record);
break;
case XLOG_BTREE_INSERT_UPPER:
btree_xlog_insert(false, false, record);
break;
case XLOG_BTREE_INSERT_META:
btree_xlog_insert(false, true, record);
break;
case XLOG_BTREE_SPLIT_L:
btree_xlog_split(true, record);
break;
case XLOG_BTREE_SPLIT_R:
btree_xlog_split(false, record);
break;
case XLOG_BTREE_VACUUM:
btree_xlog_vacuum(record);
break;
case XLOG_BTREE_DELETE:
btree_xlog_delete(record);
break;
case XLOG_BTREE_MARK_PAGE_HALFDEAD:
btree_xlog_mark_page_halfdead(info, record);
break;
case XLOG_BTREE_UNLINK_PAGE:
case XLOG_BTREE_UNLINK_PAGE_META:
btree_xlog_unlink_page(info, record);
break;
case XLOG_BTREE_NEWROOT:
btree_xlog_newroot(record);
break;
case XLOG_BTREE_REUSE_PAGE:
btree_xlog_reuse_page(record);
break;
case XLOG_BTREE_META_CLEANUP:
_bt_restore_meta(record, 0);
break;
default:
elog(PANIC, "btree_redo: unknown op code %u", info);
}
}
/*
* Mask a btree page before performing consistency checks on it.
*/
void
btree_mask(char *pagedata, BlockNumber blkno)
{
Page page = (Page) pagedata;
BTPageOpaque maskopaq;
mask_page_lsn_and_checksum(page);
mask_page_hint_bits(page);
mask_unused_space(page);
maskopaq = (BTPageOpaque) PageGetSpecialPointer(page);
if (P_ISDELETED(maskopaq))
{
/*
* Mask page content on a DELETED page since it will be re-initialized
* during replay. See btree_xlog_unlink_page() for details.
*/
mask_page_content(page);
}
else if (P_ISLEAF(maskopaq))
{
/*
* In btree leaf pages, it is possible to modify the LP_FLAGS without
* emitting any WAL record. Hence, mask the line pointer flags. See
* _bt_killitems(), _bt_check_unique() for details.
*/
mask_lp_flags(page);
}
/*
* BTP_HAS_GARBAGE is just an un-logged hint bit. So, mask it. See
* _bt_killitems(), _bt_check_unique() for details.
*/
maskopaq->btpo_flags &= ~BTP_HAS_GARBAGE;
/*
* During replay of a btree page split, we don't set the BTP_SPLIT_END
* flag of the right sibling and initialize the cycle_id to 0 for the same
* page. See btree_xlog_split() for details.
*/
maskopaq->btpo_flags &= ~BTP_SPLIT_END;
maskopaq->btpo_cycleid = 0;
}
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