/*
* Insert tuples to a given page.
*
* This is analogous with gistinserttuples() in the regular insertion code.
*
* Returns the block number of the page where the (first) new or updated tuple
* was inserted. Usually that's the original page, but might be a sibling page
* if the original page was split.
*
* Caller should hold a lock on 'buffer' on entry. This function will unlock
* and unpin it.
*/
static BlockNumber
gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer, int level,
IndexTuple *itup, int ntup, OffsetNumber oldoffnum,
BlockNumber parentblk, OffsetNumber downlinkoffnum)
{
GISTBuildBuffers *gfbb = buildstate->gfbb;
List *splitinfo;
bool is_split;
BlockNumber placed_to_blk = InvalidBlockNumber;
is_split = gistplacetopage(buildstate->indexrel,
buildstate->freespace,
buildstate->giststate,
buffer,
itup, ntup, oldoffnum, &placed_to_blk,
InvalidBuffer,
&splitinfo,
false);
/*
* If this is a root split, update the root path item kept in memory. This
* ensures that all path stacks are always complete, including all parent
* nodes up to the root. That simplifies the algorithm to re-find correct
* parent.
*/
if (is_split && BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO)
{
Page page = BufferGetPage(buffer);
OffsetNumber off;
OffsetNumber maxoff;
Assert(level == gfbb->rootlevel);
gfbb->rootlevel++;
elog(DEBUG2, "splitting GiST root page, now %d levels deep", gfbb->rootlevel);
/*
* All the downlinks on the old root page are now on one of the child
* pages. Visit all the new child pages to memorize the parents of the
* grandchildren.
*/
if (gfbb->rootlevel > 1)
{
maxoff = PageGetMaxOffsetNumber(page);
for (off = FirstOffsetNumber; off <= maxoff; off++)
{
ItemId iid = PageGetItemId(page, off);
IndexTuple idxtuple = (IndexTuple) PageGetItem(page, iid);
BlockNumber childblkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
Buffer childbuf = ReadBuffer(buildstate->indexrel, childblkno);
LockBuffer(childbuf, GIST_SHARE);
gistMemorizeAllDownlinks(buildstate, childbuf);
UnlockReleaseBuffer(childbuf);
/*
* Also remember that the parent of the new child page is the
* root block.
*/
gistMemorizeParent(buildstate, childblkno, GIST_ROOT_BLKNO);
}
}
}
if (splitinfo)
{
/*
* Insert the downlinks to the parent. This is analogous with
* gistfinishsplit() in the regular insertion code, but the locking is
* simpler, and we have to maintain the buffers on internal nodes and
* the parent map.
*/
IndexTuple *downlinks;
int ndownlinks,
i;
Buffer parentBuffer;
ListCell *lc;
/* Parent may have changed since we memorized this path. */
parentBuffer =
gistBufferingFindCorrectParent(buildstate,
BufferGetBlockNumber(buffer),
level,
&parentblk,
&downlinkoffnum);
/*
* If there's a buffer associated with this page, that needs to be
* split too. gistRelocateBuildBuffersOnSplit() will also adjust the
* downlinks in 'splitinfo', to make sure they're consistent not only
* with the tuples already on the pages, but also the tuples in the
* buffers that will eventually be inserted to them.
*/
gistRelocateBuildBuffersOnSplit(gfbb,
buildstate->giststate,
buildstate->indexrel,
level,
buffer, splitinfo);
/* Create an array of all the downlink tuples */
ndownlinks = list_length(splitinfo);
downlinks = (IndexTuple *) palloc(sizeof(IndexTuple) * ndownlinks);
i = 0;
foreach(lc, splitinfo)
{
GISTPageSplitInfo *splitinfo = lfirst(lc);
/*
* Remember the parent of each new child page in our parent map.
* This assumes that the downlinks fit on the parent page. If the
* parent page is split, too, when we recurse up to insert the
* downlinks, the recursive gistbufferinginserttuples() call will
* update the map again.
*/
if (level > 0)
gistMemorizeParent(buildstate,
BufferGetBlockNumber(splitinfo->buf),
BufferGetBlockNumber(parentBuffer));
/*
* Also update the parent map for all the downlinks that got moved
* to a different page. (actually this also loops through the
* downlinks that stayed on the original page, but it does no
* harm).
*/
if (level > 1)
gistMemorizeAllDownlinks(buildstate, splitinfo->buf);
/*
* Since there's no concurrent access, we can release the lower
* level buffers immediately. This includes the original page.
*/
UnlockReleaseBuffer(splitinfo->buf);
downlinks[i++] = splitinfo->downlink;
}
/* Insert them into parent. */
gistbufferinginserttuples(buildstate, parentBuffer, level + 1,
downlinks, ndownlinks, downlinkoffnum,
InvalidBlockNumber, InvalidOffsetNumber);
list_free_deep(splitinfo); /* we don't need this anymore */
}
/*
* Insert tuples to a given page.
*
* This is analogous with gistinserttuples() in the regular insertion code.
*/
static void
gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer,
IndexTuple *itup, int ntup, OffsetNumber oldoffnum,
GISTBufferingInsertStack *path)
{
GISTBuildBuffers *gfbb = buildstate->gfbb;
List *splitinfo;
bool is_split;
is_split = gistplacetopage(buildstate->indexrel,
buildstate->freespace,
buildstate->giststate,
buffer,
itup, ntup, oldoffnum,
InvalidBuffer,
&splitinfo,
false);
/*
* If this is a root split, update the root path item kept in memory. This
* ensures that all path stacks are always complete, including all parent
* nodes up to the root. That simplifies the algorithm to re-find correct
* parent.
*/
if (is_split && BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO)
{
GISTBufferingInsertStack *oldroot = gfbb->rootitem;
Page page = BufferGetPage(buffer);
ItemId iid;
IndexTuple idxtuple;
BlockNumber leftmostchild;
gfbb->rootitem = (GISTBufferingInsertStack *) MemoryContextAlloc(
gfbb->context, sizeof(GISTBufferingInsertStack));
gfbb->rootitem->parent = NULL;
gfbb->rootitem->blkno = GIST_ROOT_BLKNO;
gfbb->rootitem->downlinkoffnum = InvalidOffsetNumber;
gfbb->rootitem->level = oldroot->level + 1;
gfbb->rootitem->refCount = 1;
/*
* All the downlinks on the old root page are now on one of the child
* pages. Change the block number of the old root entry in the stack
* to point to the leftmost child. The other child pages will be
* accessible from there by walking right.
*/
iid = PageGetItemId(page, FirstOffsetNumber);
idxtuple = (IndexTuple) PageGetItem(page, iid);
leftmostchild = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
oldroot->parent = gfbb->rootitem;
oldroot->blkno = leftmostchild;
oldroot->downlinkoffnum = InvalidOffsetNumber;
}
if (splitinfo)
{
/*
* Insert the downlinks to the parent. This is analogous with
* gistfinishsplit() in the regular insertion code, but the locking is
* simpler, and we have to maintain the buffers.
*/
IndexTuple *downlinks;
int ndownlinks,
i;
Buffer parentBuffer;
ListCell *lc;
/* Parent may have changed since we memorized this path. */
gistBufferingFindCorrectParent(buildstate, path);
/*
* If there's a buffer associated with this page, that needs to be
* split too. gistRelocateBuildBuffersOnSplit() will also adjust the
* downlinks in 'splitinfo', to make sure they're consistent not only
* with the tuples already on the pages, but also the tuples in the
* buffers that will eventually be inserted to them.
*/
gistRelocateBuildBuffersOnSplit(gfbb,
buildstate->giststate,
buildstate->indexrel,
path, buffer, splitinfo);
/* Create an array of all the downlink tuples */
ndownlinks = list_length(splitinfo);
downlinks = (IndexTuple *) palloc(sizeof(IndexTuple) * ndownlinks);
i = 0;
foreach(lc, splitinfo)
{
GISTPageSplitInfo *splitinfo = lfirst(lc);
/*
* Since there's no concurrent access, we can release the lower
* level buffers immediately. Don't release the buffer for the
* original page, though, because the caller will release that.
*/
if (splitinfo->buf != buffer)
UnlockReleaseBuffer(splitinfo->buf);
downlinks[i++] = splitinfo->downlink;
}
/* Insert them into parent. */
parentBuffer = ReadBuffer(buildstate->indexrel, path->parent->blkno);
LockBuffer(parentBuffer, GIST_EXCLUSIVE);
gistbufferinginserttuples(buildstate, parentBuffer,
downlinks, ndownlinks,
path->downlinkoffnum, path->parent);
UnlockReleaseBuffer(parentBuffer);
list_free_deep(splitinfo); /* we don't need this anymore */
}
/*
* Process an index tuple. Runs the tuple down the tree until we reach a leaf
* page or node buffer, and inserts the tuple there. Returns true if we have
* to stop buffer emptying process (because one of child buffers can't take
* index tuples anymore).
*/
static bool
gistProcessItup(GISTBuildState *buildstate, IndexTuple itup,
BlockNumber startblkno, int startlevel)
{
GISTSTATE *giststate = buildstate->giststate;
GISTBuildBuffers *gfbb = buildstate->gfbb;
Relation indexrel = buildstate->indexrel;
BlockNumber childblkno;
Buffer buffer;
bool result = false;
BlockNumber blkno;
int level;
OffsetNumber downlinkoffnum = InvalidOffsetNumber;
BlockNumber parentblkno = InvalidBlockNumber;
CHECK_FOR_INTERRUPTS();
/*
* Loop until we reach a leaf page (level == 0) or a level with buffers
* (not including the level we start at, because we would otherwise make
* no progress).
*/
blkno = startblkno;
level = startlevel;
for (;;)
{
ItemId iid;
IndexTuple idxtuple,
newtup;
Page page;
OffsetNumber childoffnum;
/* Have we reached a level with buffers? */
if (LEVEL_HAS_BUFFERS(level, gfbb) && level != startlevel)
break;
/* Have we reached a leaf page? */
if (level == 0)
break;
/*
* Nope. Descend down to the next level then. Choose a child to
* descend down to.
*/
buffer = ReadBuffer(indexrel, blkno);
LockBuffer(buffer, GIST_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
childoffnum = gistchoose(indexrel, page, itup, giststate);
iid = PageGetItemId(page, childoffnum);
idxtuple = (IndexTuple) PageGetItem(page, iid);
childblkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
if (level > 1)
gistMemorizeParent(buildstate, childblkno, blkno);
/*
* Check that the key representing the target child node is consistent
* with the key we're inserting. Update it if it's not.
*/
newtup = gistgetadjusted(indexrel, idxtuple, itup, giststate);
if (newtup)
{
blkno = gistbufferinginserttuples(buildstate, buffer, level,
&newtup, 1, childoffnum,
InvalidBlockNumber, InvalidOffsetNumber);
/* gistbufferinginserttuples() released the buffer */
}
else
UnlockReleaseBuffer(buffer);
/* Descend to the child */
parentblkno = blkno;
blkno = childblkno;
downlinkoffnum = childoffnum;
Assert(level > 0);
level--;
}
if (LEVEL_HAS_BUFFERS(level, gfbb))
{
/*
* We've reached level with buffers. Place the index tuple to the
* buffer, and add the buffer to the emptying queue if it overflows.
*/
GISTNodeBuffer *childNodeBuffer;
/* Find the buffer or create a new one */
childNodeBuffer = gistGetNodeBuffer(gfbb, giststate, blkno, level);
/* Add index tuple to it */
gistPushItupToNodeBuffer(gfbb, childNodeBuffer, itup);
if (BUFFER_OVERFLOWED(childNodeBuffer, gfbb))
result = true;
}
else
{
/*
* We've reached a leaf page. Place the tuple here.
*/
Assert(level == 0);
buffer = ReadBuffer(indexrel, blkno);
LockBuffer(buffer, GIST_EXCLUSIVE);
gistbufferinginserttuples(buildstate, buffer, level,
&itup, 1, InvalidOffsetNumber,
parentblkno, downlinkoffnum);
/* gistbufferinginserttuples() released the buffer */
}
return result;
}
/*
* Process an index tuple. Runs the tuple down the tree until we reach a leaf
* page or node buffer, and inserts the tuple there. Returns true if we have
* to stop buffer emptying process (because one of child buffers can't take
* index tuples anymore).
*/
static bool
gistProcessItup(GISTBuildState *buildstate, IndexTuple itup,
GISTBufferingInsertStack *startparent)
{
GISTSTATE *giststate = buildstate->giststate;
GISTBuildBuffers *gfbb = buildstate->gfbb;
Relation indexrel = buildstate->indexrel;
GISTBufferingInsertStack *path;
BlockNumber childblkno;
Buffer buffer;
bool result = false;
/*
* NULL passed in startparent means that we start index tuple processing
* from the root.
*/
if (!startparent)
path = gfbb->rootitem;
else
path = startparent;
/*
* Loop until we reach a leaf page (level == 0) or a level with buffers
* (not including the level we start at, because we would otherwise make
* no progress).
*/
for (;;)
{
ItemId iid;
IndexTuple idxtuple,
newtup;
Page page;
OffsetNumber childoffnum;
GISTBufferingInsertStack *parent;
/* Have we reached a level with buffers? */
if (LEVEL_HAS_BUFFERS(path->level, gfbb) && path != startparent)
break;
/* Have we reached a leaf page? */
if (path->level == 0)
break;
/*
* Nope. Descend down to the next level then. Choose a child to
* descend down to.
*/
buffer = ReadBuffer(indexrel, path->blkno);
LockBuffer(buffer, GIST_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
childoffnum = gistchoose(indexrel, page, itup, giststate);
iid = PageGetItemId(page, childoffnum);
idxtuple = (IndexTuple) PageGetItem(page, iid);
childblkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
/*
* Check that the key representing the target child node is consistent
* with the key we're inserting. Update it if it's not.
*/
newtup = gistgetadjusted(indexrel, idxtuple, itup, giststate);
if (newtup)
gistbufferinginserttuples(buildstate, buffer, &newtup, 1,
childoffnum, path);
UnlockReleaseBuffer(buffer);
/* Create new path item representing current page */
parent = path;
path = (GISTBufferingInsertStack *) MemoryContextAlloc(gfbb->context,
sizeof(GISTBufferingInsertStack));
path->parent = parent;
path->level = parent->level - 1;
path->blkno = childblkno;
path->downlinkoffnum = childoffnum;
path->refCount = 0; /* it's unreferenced for now */
/* Adjust reference count of parent */
if (parent)
parent->refCount++;
}
if (LEVEL_HAS_BUFFERS(path->level, gfbb))
{
/*
* We've reached level with buffers. Place the index tuple to the
* buffer, and add the buffer to the emptying queue if it overflows.
*/
GISTNodeBuffer *childNodeBuffer;
/* Find the buffer or create a new one */
childNodeBuffer = gistGetNodeBuffer(gfbb, giststate, path->blkno,
path->downlinkoffnum, path->parent);
/* Add index tuple to it */
gistPushItupToNodeBuffer(gfbb, childNodeBuffer, itup);
if (BUFFER_OVERFLOWED(childNodeBuffer, gfbb))
result = true;
}
else
{
/*
* We've reached a leaf page. Place the tuple here.
*/
buffer = ReadBuffer(indexrel, path->blkno);
LockBuffer(buffer, GIST_EXCLUSIVE);
gistbufferinginserttuples(buildstate, buffer, &itup, 1,
InvalidOffsetNumber, path);
UnlockReleaseBuffer(buffer);
}
/*
* Free unreferenced path items, if any. Path item may be referenced by
* node buffer.
*/
gistFreeUnreferencedPath(path);
return result;
}
