/*
* Place tuples from 'itup' to 'buffer'. If 'oldoffnum' is valid, the tuple
* at that offset is atomically removed along with inserting the new tuples.
* This is used to replace a tuple with a new one.
*
* If 'leftchildbuf' is valid, we're inserting the downlink for the page
* to the right of 'leftchildbuf', or updating the downlink for 'leftchildbuf'.
* F_FOLLOW_RIGHT flag on 'leftchildbuf' is cleared and NSN is set.
*
* If 'markfollowright' is true and the page is split, the left child is
* marked with F_FOLLOW_RIGHT flag. That is the normal case. During buffered
* index build, however, there is no concurrent access and the page splitting
* is done in a slightly simpler fashion, and false is passed.
*
* If there is not enough room on the page, it is split. All the split
* pages are kept pinned and locked and returned in *splitinfo, the caller
* is responsible for inserting the downlinks for them. However, if
* 'buffer' is the root page and it needs to be split, gistplacetopage()
* performs the split as one atomic operation, and *splitinfo is set to NIL.
* In that case, we continue to hold the root page locked, and the child
* pages are released; note that new tuple(s) are *not* on the root page
* but in one of the new child pages.
*
* If 'newblkno' is not NULL, returns the block number of page the first
* new/updated tuple was inserted to. Usually it's the given page, but could
* be its right sibling if the page was split.
*
* Returns 'true' if the page was split, 'false' otherwise.
*/
bool
gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
Buffer buffer,
IndexTuple *itup, int ntup, OffsetNumber oldoffnum,
BlockNumber *newblkno,
Buffer leftchildbuf,
List **splitinfo,
bool markfollowright)
{
BlockNumber blkno = BufferGetBlockNumber(buffer);
Page page = BufferGetPage(buffer);
bool is_leaf = (GistPageIsLeaf(page)) ? true : false;
XLogRecPtr recptr;
int i;
bool is_split;
/*
* Refuse to modify a page that's incompletely split. This should not
* happen because we finish any incomplete splits while we walk down the
* tree. However, it's remotely possible that another concurrent inserter
* splits a parent page, and errors out before completing the split. We
* will just throw an error in that case, and leave any split we had in
* progress unfinished too. The next insert that comes along will clean up
* the mess.
*/
if (GistFollowRight(page))
elog(ERROR, "concurrent GiST page split was incomplete");
*splitinfo = NIL;
/*
* if isupdate, remove old key: This node's key has been modified, either
* because a child split occurred or because we needed to adjust our key
* for an insert in a child node. Therefore, remove the old version of
* this node's key.
*
* for WAL replay, in the non-split case we handle this by setting up a
* one-element todelete array; in the split case, it's handled implicitly
* because the tuple vector passed to gistSplit won't include this tuple.
*/
is_split = gistnospace(page, itup, ntup, oldoffnum, freespace);
if (is_split)
{
/* no space for insertion */
IndexTuple *itvec;
int tlen;
SplitedPageLayout *dist = NULL,
*ptr;
BlockNumber oldrlink = InvalidBlockNumber;
GistNSN oldnsn = 0;
SplitedPageLayout rootpg;
bool is_rootsplit;
is_rootsplit = (blkno == GIST_ROOT_BLKNO);
/*
* Form index tuples vector to split. If we're replacing an old tuple,
* remove the old version from the vector.
*/
itvec = gistextractpage(page, &tlen);
if (OffsetNumberIsValid(oldoffnum))
{
/* on inner page we should remove old tuple */
int pos = oldoffnum - FirstOffsetNumber;
tlen--;
if (pos != tlen)
memmove(itvec + pos, itvec + pos + 1, sizeof(IndexTuple) * (tlen - pos));
}
itvec = gistjoinvector(itvec, &tlen, itup, ntup);
dist = gistSplit(rel, page, itvec, tlen, giststate);
/*
* Set up pages to work with. Allocate new buffers for all but the
* leftmost page. The original page becomes the new leftmost page, and
* is just replaced with the new contents.
*
* For a root-split, allocate new buffers for all child pages, the
* original page is overwritten with new root page containing
* downlinks to the new child pages.
*/
ptr = dist;
if (!is_rootsplit)
{
/* save old rightlink and NSN */
oldrlink = GistPageGetOpaque(page)->rightlink;
oldnsn = GistPageGetNSN(page);
dist->buffer = buffer;
dist->block.blkno = BufferGetBlockNumber(buffer);
dist->page = PageGetTempPageCopySpecial(BufferGetPage(buffer));
/* clean all flags except F_LEAF */
GistPageGetOpaque(dist->page)->flags = (is_leaf) ? F_LEAF : 0;
ptr = ptr->next;
}
for (; ptr; ptr = ptr->next)
{
/* Allocate new page */
ptr->buffer = gistNewBuffer(rel);
GISTInitBuffer(ptr->buffer, (is_leaf) ? F_LEAF : 0);
ptr->page = BufferGetPage(ptr->buffer);
ptr->block.blkno = BufferGetBlockNumber(ptr->buffer);
}
/*
* Now that we know which blocks the new pages go to, set up downlink
* tuples to point to them.
*/
for (ptr = dist; ptr; ptr = ptr->next)
{
ItemPointerSetBlockNumber(&(ptr->itup->t_tid), ptr->block.blkno);
GistTupleSetValid(ptr->itup);
}
/*
* If this is a root split, we construct the new root page with the
* downlinks here directly, instead of requiring the caller to insert
* them. Add the new root page to the list along with the child pages.
*/
if (is_rootsplit)
{
IndexTuple *downlinks;
int ndownlinks = 0;
int i;
rootpg.buffer = buffer;
rootpg.page = PageGetTempPageCopySpecial(BufferGetPage(rootpg.buffer));
GistPageGetOpaque(rootpg.page)->flags = 0;
/* Prepare a vector of all the downlinks */
for (ptr = dist; ptr; ptr = ptr->next)
ndownlinks++;
downlinks = palloc(sizeof(IndexTuple) * ndownlinks);
for (i = 0, ptr = dist; ptr; ptr = ptr->next)
downlinks[i++] = ptr->itup;
rootpg.block.blkno = GIST_ROOT_BLKNO;
rootpg.block.num = ndownlinks;
rootpg.list = gistfillitupvec(downlinks, ndownlinks,
&(rootpg.lenlist));
rootpg.itup = NULL;
rootpg.next = dist;
dist = &rootpg;
}
else
{
/* Prepare split-info to be returned to caller */
for (ptr = dist; ptr; ptr = ptr->next)
{
GISTPageSplitInfo *si = palloc(sizeof(GISTPageSplitInfo));
si->buf = ptr->buffer;
si->downlink = ptr->itup;
*splitinfo = lappend(*splitinfo, si);
}
}
/*
* Fill all pages. All the pages are new, ie. freshly allocated empty
* pages, or a temporary copy of the old page.
*/
for (ptr = dist; ptr; ptr = ptr->next)
{
char *data = (char *) (ptr->list);
for (i = 0; i < ptr->block.num; i++)
{
IndexTuple thistup = (IndexTuple) data;
if (PageAddItem(ptr->page, (Item) data, IndexTupleSize(thistup), i + FirstOffsetNumber, false, false) == InvalidOffsetNumber)
elog(ERROR, "failed to add item to index page in \"%s\"", RelationGetRelationName(rel));
/*
* If this is the first inserted/updated tuple, let the caller
* know which page it landed on.
*/
if (newblkno && ItemPointerEquals(&thistup->t_tid, &(*itup)->t_tid))
*newblkno = ptr->block.blkno;
data += IndexTupleSize(thistup);
}
/* Set up rightlinks */
if (ptr->next && ptr->block.blkno != GIST_ROOT_BLKNO)
GistPageGetOpaque(ptr->page)->rightlink =
ptr->next->block.blkno;
else
GistPageGetOpaque(ptr->page)->rightlink = oldrlink;
/*
* Mark the all but the right-most page with the follow-right
* flag. It will be cleared as soon as the downlink is inserted
* into the parent, but this ensures that if we error out before
* that, the index is still consistent. (in buffering build mode,
* any error will abort the index build anyway, so this is not
* needed.)
*/
if (ptr->next && !is_rootsplit && markfollowright)
GistMarkFollowRight(ptr->page);
else
GistClearFollowRight(ptr->page);
/*
* Copy the NSN of the original page to all pages. The
* F_FOLLOW_RIGHT flags ensure that scans will follow the
* rightlinks until the downlinks are inserted.
*/
GistPageSetNSN(ptr->page, oldnsn);
}
START_CRIT_SECTION();
/*
* Must mark buffers dirty before XLogInsert, even though we'll still
* be changing their opaque fields below.
*/
for (ptr = dist; ptr; ptr = ptr->next)
MarkBufferDirty(ptr->buffer);
if (BufferIsValid(leftchildbuf))
MarkBufferDirty(leftchildbuf);
/*
* The first page in the chain was a temporary working copy meant to
* replace the old page. Copy it over the old page.
*/
PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
dist->page = BufferGetPage(dist->buffer);
/* Write the WAL record */
if (RelationNeedsWAL(rel))
recptr = gistXLogSplit(rel->rd_node, blkno, is_leaf,
dist, oldrlink, oldnsn, leftchildbuf,
markfollowright);
else
recptr = gistGetFakeLSN(rel);
for (ptr = dist; ptr; ptr = ptr->next)
{
PageSetLSN(ptr->page, recptr);
}
/*
* Return the new child buffers to the caller.
*
* If this was a root split, we've already inserted the downlink
* pointers, in the form of a new root page. Therefore we can release
* all the new buffers, and keep just the root page locked.
*/
if (is_rootsplit)
{
for (ptr = dist->next; ptr; ptr = ptr->next)
UnlockReleaseBuffer(ptr->buffer);
}
}
else
{
/*
* Enough space. We also get here if ntuples==0.
*/
START_CRIT_SECTION();
if (OffsetNumberIsValid(oldoffnum))
PageIndexTupleDelete(page, oldoffnum);
gistfillbuffer(page, itup, ntup, InvalidOffsetNumber);
MarkBufferDirty(buffer);
if (BufferIsValid(leftchildbuf))
MarkBufferDirty(leftchildbuf);
if (RelationNeedsWAL(rel))
{
OffsetNumber ndeloffs = 0,
deloffs[1];
if (OffsetNumberIsValid(oldoffnum))
{
deloffs[0] = oldoffnum;
ndeloffs = 1;
}
recptr = gistXLogUpdate(rel->rd_node, buffer,
deloffs, ndeloffs, itup, ntup,
leftchildbuf);
PageSetLSN(page, recptr);
}
else
{
recptr = gistGetFakeLSN(rel);
PageSetLSN(page, recptr);
}
if (newblkno)
*newblkno = blkno;
}
/*
* If we inserted the downlink for a child page, set NSN and clear
* F_FOLLOW_RIGHT flag on the left child, so that concurrent scans know to
* follow the rightlink if and only if they looked at the parent page
* before we inserted the downlink.
*
* Note that we do this *after* writing the WAL record. That means that
* the possible full page image in the WAL record does not include these
* changes, and they must be replayed even if the page is restored from
* the full page image. There's a chicken-and-egg problem: if we updated
* the child pages first, we wouldn't know the recptr of the WAL record
* we're about to write.
*/
if (BufferIsValid(leftchildbuf))
{
Page leftpg = BufferGetPage(leftchildbuf);
GistPageSetNSN(leftpg, recptr);
GistClearFollowRight(leftpg);
PageSetLSN(leftpg, recptr);
}
END_CRIT_SECTION();
return is_split;
}
static ArrayTuple
vacuumSplitPage(GistVacuum *gv, Page tempPage, Buffer buffer, IndexTuple *addon, int curlenaddon)
{
ArrayTuple res = {NULL, 0, false};
IndexTuple *vec;
SplitedPageLayout *dist = NULL,
*ptr;
int i,
veclen = 0;
BlockNumber blkno = BufferGetBlockNumber(buffer);
MemoryContext oldCtx = MemoryContextSwitchTo(gv->opCtx);
vec = gistextractpage(tempPage, &veclen);
vec = gistjoinvector(vec, &veclen, addon, curlenaddon);
dist = gistSplit(gv->index, tempPage, vec, veclen, &(gv->giststate));
MemoryContextSwitchTo(oldCtx);
if (blkno != GIST_ROOT_BLKNO)
{
/* if non-root split then we should not allocate new buffer */
dist->buffer = buffer;
dist->page = tempPage;
/* during vacuum we never split leaf page */
GistPageGetOpaque(dist->page)->flags = 0;
}
else
pfree(tempPage);
res.itup = (IndexTuple *) palloc(sizeof(IndexTuple) * veclen);
res.ituplen = 0;
/* make new pages and fills them */
for (ptr = dist; ptr; ptr = ptr->next)
{
char *data;
if (ptr->buffer == InvalidBuffer)
{
ptr->buffer = gistNewBuffer(gv->index);
GISTInitBuffer(ptr->buffer, 0);
ptr->page = BufferGetPage(ptr->buffer);
}
ptr->block.blkno = BufferGetBlockNumber(ptr->buffer);
data = (char *) (ptr->list);
for (i = 0; i < ptr->block.num; i++)
{
if (PageAddItem(ptr->page, (Item) data, IndexTupleSize((IndexTuple) data), i + FirstOffsetNumber, false, false) == InvalidOffsetNumber)
elog(ERROR, "failed to add item to index page in \"%s\"", RelationGetRelationName(gv->index));
data += IndexTupleSize((IndexTuple) data);
}
ItemPointerSetBlockNumber(&(ptr->itup->t_tid), ptr->block.blkno);
res.itup[res.ituplen] = (IndexTuple) palloc(IndexTupleSize(ptr->itup));
memcpy(res.itup[res.ituplen], ptr->itup, IndexTupleSize(ptr->itup));
res.ituplen++;
}
START_CRIT_SECTION();
for (ptr = dist; ptr; ptr = ptr->next)
{
MarkBufferDirty(ptr->buffer);
GistPageGetOpaque(ptr->page)->rightlink = InvalidBlockNumber;
}
/* restore splitted non-root page */
if (blkno != GIST_ROOT_BLKNO)
{
PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
dist->page = BufferGetPage(dist->buffer);
}
if (!gv->index->rd_istemp)
{
XLogRecPtr recptr;
XLogRecData *rdata;
ItemPointerData key; /* set key for incomplete insert */
char *xlinfo;
ItemPointerSet(&key, blkno, TUPLE_IS_VALID);
rdata = formSplitRdata(gv->index->rd_node, blkno,
false, &key, dist);
xlinfo = rdata->data;
recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_PAGE_SPLIT, rdata);
for (ptr = dist; ptr; ptr = ptr->next)
{
PageSetLSN(BufferGetPage(ptr->buffer), recptr);
PageSetTLI(BufferGetPage(ptr->buffer), ThisTimeLineID);
}
pfree(xlinfo);
pfree(rdata);
}
else
{
for (ptr = dist; ptr; ptr = ptr->next)
PageSetLSN(BufferGetPage(ptr->buffer), XLogRecPtrForTemp);
}
for (ptr = dist; ptr; ptr = ptr->next)
{
/* we must keep the buffer pin on the head page */
if (BufferGetBlockNumber(ptr->buffer) != blkno)
UnlockReleaseBuffer(ptr->buffer);
}
if (blkno == GIST_ROOT_BLKNO)
{
ItemPointerData key; /* set key for incomplete insert */
ItemPointerSet(&key, blkno, TUPLE_IS_VALID);
gistnewroot(gv->index, buffer, res.itup, res.ituplen, &key);
}
END_CRIT_SECTION();
MemoryContextReset(gv->opCtx);
return res;
}
static int
gistlayerinsert(Relation r, BlockNumber blkno,
IndexTuple **itup, /* in - out, has compressed entry */
int *len, /* in - out */
InsertIndexResult *res, /* out */
GISTSTATE *giststate)
{
Buffer buffer;
Page page;
OffsetNumber child;
int ret;
GISTPageOpaque opaque;
buffer = ReadBuffer(r, blkno);
page = (Page) BufferGetPage(buffer);
opaque = (GISTPageOpaque) PageGetSpecialPointer(page);
if (!(opaque->flags & F_LEAF))
{
/* internal page, so we must walk on tree */
/* len IS equal 1 */
ItemId iid;
BlockNumber nblkno;
ItemPointerData oldtid;
IndexTuple oldtup;
child = gistchoose(r, page, *(*itup), giststate);
iid = PageGetItemId(page, child);
oldtup = (IndexTuple) PageGetItem(page, iid);
nblkno = ItemPointerGetBlockNumber(&(oldtup->t_tid));
/*
* After this call: 1. if child page was splited, then itup
* contains keys for each page 2. if child page wasn't splited,
* then itup contains additional for adjustment of current key
*/
ret = gistlayerinsert(r, nblkno, itup, len, res, giststate);
/* nothing inserted in child */
if (!(ret & INSERTED))
{
ReleaseBuffer(buffer);
return 0x00;
}
/* child does not splited */
if (!(ret & SPLITED))
{
IndexTuple newtup = gistgetadjusted(r, oldtup, (*itup)[0], giststate);
if (!newtup)
{
/* not need to update key */
ReleaseBuffer(buffer);
return 0x00;
}
pfree((*itup)[0]); /* !!! */
(*itup)[0] = newtup;
}
/* key is modified, so old version must be deleted */
ItemPointerSet(&oldtid, blkno, child);
gistdelete(r, &oldtid);
/*
* if child was splitted, new key for child will be inserted in
* the end list of child, so we must say to any scans that page is
* changed beginning from 'child' offset
*/
if (ret & SPLITED)
gistadjscans(r, GISTOP_SPLIT, blkno, child);
}
ret = INSERTED;
if (gistnospace(page, (*itup), *len))
{
/* no space for insertion */
IndexTuple *itvec,
*newitup;
int tlen,
oldlen;
ret |= SPLITED;
itvec = gistreadbuffer(buffer, &tlen);
itvec = gistjoinvector(itvec, &tlen, (*itup), *len);
oldlen = *len;
newitup = gistSplit(r, buffer, itvec, &tlen, giststate,
(opaque->flags & F_LEAF) ? res : NULL); /* res only for
* inserting in leaf */
ReleaseBuffer(buffer);
do
pfree((*itup)[oldlen - 1]);
while ((--oldlen) > 0);
pfree((*itup));
pfree(itvec);
*itup = newitup;
*len = tlen; /* now tlen >= 2 */
}
else
{
/* enogth space */
OffsetNumber off,
l;
off = (PageIsEmpty(page)) ?
FirstOffsetNumber
:
OffsetNumberNext(PageGetMaxOffsetNumber(page));
l = gistwritebuffer(r, page, (*itup), *len, off);
WriteBuffer(buffer);
/*
* set res if insert into leaf page, in this case, len = 1 always
*/
if (res && (opaque->flags & F_LEAF))
ItemPointerSet(&((*res)->pointerData), blkno, l);
if (*len > 1)
{ /* previous insert ret & SPLITED != 0 */
int i;
/*
* child was splited, so we must form union for insertion in
* parent
*/
IndexTuple newtup = gistunion(r, (*itup), *len, giststate);
ItemPointerSet(&(newtup->t_tid), blkno, 1);
for (i = 0; i < *len; i++)
pfree((*itup)[i]);
(*itup)[0] = newtup;
*len = 1;
}
}
return ret;
}
static bool
gistplacetopage(GISTInsertState *state, GISTSTATE *giststate)
{
bool is_splitted = false;
bool is_leaf = (GistPageIsLeaf(state->stack->page)) ? true : false;
MIRROREDLOCK_BUFMGR_MUST_ALREADY_BE_HELD;
/*
* if (!is_leaf) remove old key: This node's key has been modified, either
* because a child split occurred or because we needed to adjust our key
* for an insert in a child node. Therefore, remove the old version of
* this node's key.
*
* for WAL replay, in the non-split case we handle this by setting up a
* one-element todelete array; in the split case, it's handled implicitly
* because the tuple vector passed to gistSplit won't include this tuple.
*
* XXX: If we want to change fillfactors between node and leaf, fillfactor
* = (is_leaf ? state->leaf_fillfactor : state->node_fillfactor)
*/
if (gistnospace(state->stack->page, state->itup, state->ituplen,
is_leaf ? InvalidOffsetNumber : state->stack->childoffnum,
state->freespace))
{
/* no space for insertion */
IndexTuple *itvec;
int tlen;
SplitedPageLayout *dist = NULL,
*ptr;
BlockNumber rrlink = InvalidBlockNumber;
GistNSN oldnsn;
is_splitted = true;
/*
* Form index tuples vector to split: remove old tuple if t's needed
* and add new tuples to vector
*/
itvec = gistextractpage(state->stack->page, &tlen);
if (!is_leaf)
{
/* on inner page we should remove old tuple */
int pos = state->stack->childoffnum - FirstOffsetNumber;
tlen--;
if (pos != tlen)
memmove(itvec + pos, itvec + pos + 1, sizeof(IndexTuple) * (tlen - pos));
}
itvec = gistjoinvector(itvec, &tlen, state->itup, state->ituplen);
dist = gistSplit(state->r, state->stack->page, itvec, tlen, giststate);
state->itup = (IndexTuple *) palloc(sizeof(IndexTuple) * tlen);
state->ituplen = 0;
if (state->stack->blkno != GIST_ROOT_BLKNO)
{
/*
* if non-root split then we should not allocate new buffer, but
* we must create temporary page to operate
*/
dist->buffer = state->stack->buffer;
dist->page = PageGetTempPage(BufferGetPage(dist->buffer), sizeof(GISTPageOpaqueData));
/* clean all flags except F_LEAF */
GistPageGetOpaque(dist->page)->flags = (is_leaf) ? F_LEAF : 0;
}
/* make new pages and fills them */
for (ptr = dist; ptr; ptr = ptr->next)
{
int i;
char *data;
/* get new page */
if (ptr->buffer == InvalidBuffer)
{
ptr->buffer = gistNewBuffer(state->r);
GISTInitBuffer(ptr->buffer, (is_leaf) ? F_LEAF : 0);
ptr->page = BufferGetPage(ptr->buffer);
}
ptr->block.blkno = BufferGetBlockNumber(ptr->buffer);
/*
* fill page, we can do it because all these pages are new
* (ie not linked in tree or masked by temp page
*/
data = (char *) (ptr->list);
for (i = 0; i < ptr->block.num; i++)
{
if (PageAddItem(ptr->page, (Item) data, IndexTupleSize((IndexTuple) data), i + FirstOffsetNumber, LP_USED) == InvalidOffsetNumber)
elog(ERROR, "failed to add item to index page in \"%s\"", RelationGetRelationName(state->r));
data += IndexTupleSize((IndexTuple) data);
}
/* set up ItemPointer and remember it for parent */
ItemPointerSetBlockNumber(&(ptr->itup->t_tid), ptr->block.blkno);
state->itup[state->ituplen] = ptr->itup;
state->ituplen++;
}
/* saves old rightlink */
if (state->stack->blkno != GIST_ROOT_BLKNO)
rrlink = GistPageGetOpaque(dist->page)->rightlink;
START_CRIT_SECTION();
/*
* must mark buffers dirty before XLogInsert, even though we'll still
* be changing their opaque fields below. set up right links.
*/
for (ptr = dist; ptr; ptr = ptr->next)
{
MarkBufferDirty(ptr->buffer);
GistPageGetOpaque(ptr->page)->rightlink = (ptr->next) ?
ptr->next->block.blkno : rrlink;
}
/* restore splitted non-root page */
if (state->stack->blkno != GIST_ROOT_BLKNO)
{
PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
dist->page = BufferGetPage(dist->buffer);
}
if (!state->r->rd_istemp)
{
XLogRecPtr recptr;
XLogRecData *rdata;
rdata = formSplitRdata(state->r, state->stack->blkno,
is_leaf, &(state->key), dist);
recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_PAGE_SPLIT, rdata);
for (ptr = dist; ptr; ptr = ptr->next)
{
PageSetLSN(ptr->page, recptr);
PageSetTLI(ptr->page, ThisTimeLineID);
}
}
else
{
for (ptr = dist; ptr; ptr = ptr->next)
{
PageSetLSN(ptr->page, XLogRecPtrForTemp);
}
}
/* set up NSN */
oldnsn = GistPageGetOpaque(dist->page)->nsn;
if (state->stack->blkno == GIST_ROOT_BLKNO)
/* if root split we should put initial value */
oldnsn = PageGetLSN(dist->page);
for (ptr = dist; ptr; ptr = ptr->next)
{
/* only for last set oldnsn */
GistPageGetOpaque(ptr->page)->nsn = (ptr->next) ?
PageGetLSN(ptr->page) : oldnsn;
}
/*
* release buffers, if it was a root split then release all buffers
* because we create all buffers
*/
ptr = (state->stack->blkno == GIST_ROOT_BLKNO) ? dist : dist->next;
for (; ptr; ptr = ptr->next)
UnlockReleaseBuffer(ptr->buffer);
if (state->stack->blkno == GIST_ROOT_BLKNO)
{
gistnewroot(state->r, state->stack->buffer, state->itup, state->ituplen, &(state->key));
state->needInsertComplete = false;
}
END_CRIT_SECTION();
}
else
{
/* enough space */
START_CRIT_SECTION();
if (!is_leaf)
PageIndexTupleDelete(state->stack->page, state->stack->childoffnum);
gistfillbuffer(state->r, state->stack->page, state->itup, state->ituplen, InvalidOffsetNumber);
MarkBufferDirty(state->stack->buffer);
if (!state->r->rd_istemp)
{
OffsetNumber noffs = 0,
offs[1];
XLogRecPtr recptr;
XLogRecData *rdata;
if (!is_leaf)
{
/* only on inner page we should delete previous version */
offs[0] = state->stack->childoffnum;
noffs = 1;
}
rdata = formUpdateRdata(state->r, state->stack->buffer,
offs, noffs,
state->itup, state->ituplen,
&(state->key));
recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_PAGE_UPDATE, rdata);
PageSetLSN(state->stack->page, recptr);
PageSetTLI(state->stack->page, ThisTimeLineID);
}
else
PageSetLSN(state->stack->page, XLogRecPtrForTemp);
if (state->stack->blkno == GIST_ROOT_BLKNO)
state->needInsertComplete = false;
END_CRIT_SECTION();
if (state->ituplen > 1)
{ /* previous is_splitted==true */
/*
* child was splited, so we must form union for insertion in
* parent
*/
IndexTuple newtup = gistunion(state->r, state->itup, state->ituplen, giststate);
ItemPointerSetBlockNumber(&(newtup->t_tid), state->stack->blkno);
state->itup[0] = newtup;
state->ituplen = 1;
}
else if (is_leaf)
{
/*
* itup[0] store key to adjust parent, we set it to valid to
* correct check by GistTupleIsInvalid macro in gistgetadjusted()
*/
ItemPointerSetBlockNumber(&(state->itup[0]->t_tid), state->stack->blkno);
GistTupleSetValid(state->itup[0]);
}
}
return is_splitted;
}
/*
* gistSplit -- split a page in the tree.
*/
static IndexTuple *
gistSplit(Relation r,
Buffer buffer,
IndexTuple *itup, /* contains compressed entry */
int *len,
GISTSTATE *giststate,
InsertIndexResult *res)
{
Page p;
Buffer leftbuf,
rightbuf;
Page left,
right;
IndexTuple *lvectup,
*rvectup,
*newtup;
BlockNumber lbknum,
rbknum;
GISTPageOpaque opaque;
GIST_SPLITVEC v;
GistEntryVector *entryvec;
bool *decompvec;
int i,
j,
nlen;
int MaxGrpId = 1;
Datum datum;
bool IsNull;
p = (Page) BufferGetPage(buffer);
opaque = (GISTPageOpaque) PageGetSpecialPointer(p);
/*
* The root of the tree is the first block in the relation. If we're
* about to split the root, we need to do some hocus-pocus to enforce
* this guarantee.
*/
if (BufferGetBlockNumber(buffer) == GISTP_ROOT)
{
leftbuf = ReadBuffer(r, P_NEW);
GISTInitBuffer(leftbuf, opaque->flags);
lbknum = BufferGetBlockNumber(leftbuf);
left = (Page) BufferGetPage(leftbuf);
}
else
{
leftbuf = buffer;
IncrBufferRefCount(buffer);
lbknum = BufferGetBlockNumber(buffer);
left = (Page) PageGetTempPage(p, sizeof(GISTPageOpaqueData));
}
rightbuf = ReadBuffer(r, P_NEW);
GISTInitBuffer(rightbuf, opaque->flags);
rbknum = BufferGetBlockNumber(rightbuf);
right = (Page) BufferGetPage(rightbuf);
/* generate the item array */
entryvec = palloc(GEVHDRSZ + (*len + 1) * sizeof(GISTENTRY));
entryvec->n = *len + 1;
decompvec = (bool *) palloc((*len + 1) * sizeof(bool));
for (i = 1; i <= *len; i++)
{
datum = index_getattr(itup[i - 1], 1, giststate->tupdesc, &IsNull);
gistdentryinit(giststate, 0, &(entryvec->vector[i]),
datum, r, p, i,
ATTSIZE(datum, giststate->tupdesc, 1, IsNull), FALSE, IsNull);
if ((!isAttByVal(giststate, 0)) && entryvec->vector[i].key != datum)
decompvec[i] = TRUE;
else
decompvec[i] = FALSE;
}
/*
* now let the user-defined picksplit function set up the split
* vector; in entryvec have no null value!!
*/
FunctionCall2(&giststate->picksplitFn[0],
PointerGetDatum(entryvec),
PointerGetDatum(&v));
/* compatibility with old code */
if (v.spl_left[v.spl_nleft - 1] == InvalidOffsetNumber)
v.spl_left[v.spl_nleft - 1] = (OffsetNumber) *len;
if (v.spl_right[v.spl_nright - 1] == InvalidOffsetNumber)
v.spl_right[v.spl_nright - 1] = (OffsetNumber) *len;
v.spl_lattr[0] = v.spl_ldatum;
v.spl_rattr[0] = v.spl_rdatum;
v.spl_lisnull[0] = false;
v.spl_risnull[0] = false;
/*
* if index is multikey, then we must to try get smaller bounding box
* for subkey(s)
*/
if (r->rd_att->natts > 1)
{
v.spl_idgrp = (int *) palloc0(sizeof(int) * (*len + 1));
v.spl_grpflag = (char *) palloc0(sizeof(char) * (*len + 1));
v.spl_ngrp = (int *) palloc(sizeof(int) * (*len + 1));
MaxGrpId = gistfindgroup(giststate, entryvec->vector, &v);
/* form union of sub keys for each page (l,p) */
gistunionsubkey(r, giststate, itup, &v);
/*
* if possible, we insert equivalent tuples with control by
* penalty for a subkey(s)
*/
if (MaxGrpId > 1)
gistadjsubkey(r, itup, len, &v, giststate);
pfree(v.spl_idgrp);
pfree(v.spl_grpflag);
pfree(v.spl_ngrp);
}
/* clean up the entry vector: its keys need to be deleted, too */
for (i = 1; i <= *len; i++)
if (decompvec[i])
pfree(DatumGetPointer(entryvec->vector[i].key));
pfree(entryvec);
pfree(decompvec);
/* form left and right vector */
lvectup = (IndexTuple *) palloc(sizeof(IndexTuple) * v.spl_nleft);
rvectup = (IndexTuple *) palloc(sizeof(IndexTuple) * v.spl_nright);
for (i = 0; i < v.spl_nleft; i++)
lvectup[i] = itup[v.spl_left[i] - 1];
for (i = 0; i < v.spl_nright; i++)
rvectup[i] = itup[v.spl_right[i] - 1];
/* write on disk (may be need another split) */
if (gistnospace(right, rvectup, v.spl_nright))
{
nlen = v.spl_nright;
newtup = gistSplit(r, rightbuf, rvectup, &nlen, giststate,
(res && rvectup[nlen - 1] == itup[*len - 1]) ? res : NULL);
ReleaseBuffer(rightbuf);
for (j = 1; j < r->rd_att->natts; j++)
if ((!isAttByVal(giststate, j)) && !v.spl_risnull[j])
pfree(DatumGetPointer(v.spl_rattr[j]));
}
else
{
OffsetNumber l;
l = gistwritebuffer(r, right, rvectup, v.spl_nright, FirstOffsetNumber);
WriteBuffer(rightbuf);
if (res)
ItemPointerSet(&((*res)->pointerData), rbknum, l);
nlen = 1;
newtup = (IndexTuple *) palloc(sizeof(IndexTuple) * 1);
newtup[0] = gistFormTuple(giststate, r, v.spl_rattr, v.spl_rattrsize, v.spl_risnull);
ItemPointerSet(&(newtup[0]->t_tid), rbknum, 1);
}
if (gistnospace(left, lvectup, v.spl_nleft))
{
int llen = v.spl_nleft;
IndexTuple *lntup;
lntup = gistSplit(r, leftbuf, lvectup, &llen, giststate,
(res && lvectup[llen - 1] == itup[*len - 1]) ? res : NULL);
ReleaseBuffer(leftbuf);
for (j = 1; j < r->rd_att->natts; j++)
if ((!isAttByVal(giststate, j)) && !v.spl_lisnull[j])
pfree(DatumGetPointer(v.spl_lattr[j]));
newtup = gistjoinvector(newtup, &nlen, lntup, llen);
pfree(lntup);
}
else
{
OffsetNumber l;
l = gistwritebuffer(r, left, lvectup, v.spl_nleft, FirstOffsetNumber);
if (BufferGetBlockNumber(buffer) != GISTP_ROOT)
PageRestoreTempPage(left, p);
WriteBuffer(leftbuf);
if (res)
ItemPointerSet(&((*res)->pointerData), lbknum, l);
nlen += 1;
newtup = (IndexTuple *) repalloc((void *) newtup, sizeof(IndexTuple) * nlen);
newtup[nlen - 1] = gistFormTuple(giststate, r, v.spl_lattr, v.spl_lattrsize, v.spl_lisnull);
ItemPointerSet(&(newtup[nlen - 1]->t_tid), lbknum, 1);
}
/* !!! pfree */
pfree(rvectup);
pfree(lvectup);
pfree(v.spl_left);
pfree(v.spl_right);
*len = nlen;
return newtup;
}