/*
* Allocate and initialize a new buffer of the type and parity specified by
* flags. The returned buffer is already pinned and exclusive-locked.
*
* When requesting an inner page, if we get one with the wrong parity,
* we just release the buffer and try again. We will get a different page
* because GetFreeIndexPage will have marked the page used in FSM. The page
* is entered in our local lastUsedPages cache, so there's some hope of
* making use of it later in this session, but otherwise we rely on VACUUM
* to eventually re-enter the page in FSM, making it available for recycling.
* Note that such a page does not get marked dirty here, so unless it's used
* fairly soon, the buffer will just get discarded and the page will remain
* as it was on disk.
*
* When we return a buffer to the caller, the page is *not* entered into
* the lastUsedPages cache; we expect the caller will do so after it's taken
* whatever space it will use. This is because after the caller has used up
* some space, the page might have less space than whatever was cached already
* so we'd rather not trash the old cache entry.
*/
static Buffer
allocNewBuffer(Relation index, int flags)
{
SpGistCache *cache = spgGetCache(index);
uint16 pageflags = 0;
if (GBUF_REQ_LEAF(flags))
pageflags |= SPGIST_LEAF;
if (GBUF_REQ_NULLS(flags))
pageflags |= SPGIST_NULLS;
for (;;)
{
Buffer buffer;
buffer = SpGistNewBuffer(index);
SpGistInitBuffer(buffer, pageflags);
if (pageflags & SPGIST_LEAF)
{
/* Leaf pages have no parity concerns, so just use it */
return buffer;
}
else
{
BlockNumber blkno = BufferGetBlockNumber(buffer);
int blkFlags = GBUF_INNER_PARITY(blkno);
if ((flags & GBUF_PARITY_MASK) == blkFlags)
{
/* Page has right parity, use it */
return buffer;
}
else
{
/* Page has wrong parity, record it in cache and try again */
if (pageflags & SPGIST_NULLS)
blkFlags |= GBUF_NULLS;
cache->lastUsedPages.cachedPage[blkFlags].blkno = blkno;
cache->lastUsedPages.cachedPage[blkFlags].freeSpace =
PageGetExactFreeSpace(BufferGetPage(buffer));
UnlockReleaseBuffer(buffer);
}
}
}
}
/*
* Allocate and initialize a new buffer of the type and parity specified by
* flags. The returned buffer is already pinned and exclusive-locked.
*
* When requesting an inner page, if we get one with the wrong parity,
* we just release the buffer and try again. We will get a different page
* because GetFreeIndexPage will have marked the page used in FSM. The page
* is entered in our local lastUsedPages cache, so there's some hope of
* making use of it later in this session, but otherwise we rely on VACUUM
* to eventually re-enter the page in FSM, making it available for recycling.
* Note that such a page does not get marked dirty here, so unless it's used
* fairly soon, the buffer will just get discarded and the page will remain
* as it was on disk.
*
* When we return a buffer to the caller, the page is *not* entered into
* the lastUsedPages cache; we expect the caller will do so after it's taken
* whatever space it will use. This is because after the caller has used up
* some space, the page might have less space than whatever was cached already
* so we'd rather not trash the old cache entry.
*/
static Buffer
allocNewBuffer(Relation index, int flags)
{
SpGistCache *cache = spgGetCache(index);
for (;;)
{
Buffer buffer;
buffer = SpGistNewBuffer(index);
SpGistInitBuffer(buffer, (flags & GBUF_LEAF) ? SPGIST_LEAF : 0);
if (flags & GBUF_LEAF)
{
/* Leaf pages have no parity concerns, so just use it */
return buffer;
}
else
{
BlockNumber blkno = BufferGetBlockNumber(buffer);
int blkParity = blkno % 3;
if ((flags & GBUF_PARITY_MASK) == blkParity)
{
/* Page has right parity, use it */
return buffer;
}
else
{
/* Page has wrong parity, record it in cache and try again */
cache->lastUsedPages.innerPage[blkParity].blkno = blkno;
cache->lastUsedPages.innerPage[blkParity].freeSpace =
PageGetExactFreeSpace(BufferGetPage(buffer));
UnlockReleaseBuffer(buffer);
}
}
}
}
/*
* Build an SP-GiST index.
*/
Datum
spgbuild(PG_FUNCTION_ARGS)
{
Relation heap = (Relation) PG_GETARG_POINTER(0);
Relation index = (Relation) PG_GETARG_POINTER(1);
IndexInfo *indexInfo = (IndexInfo *) PG_GETARG_POINTER(2);
IndexBuildResult *result;
double reltuples;
SpGistBuildState buildstate;
Buffer metabuffer,
rootbuffer;
if (RelationGetNumberOfBlocks(index) != 0)
elog(ERROR, "index \"%s\" already contains data",
RelationGetRelationName(index));
/*
* Initialize the meta page and root page
*/
metabuffer = SpGistNewBuffer(index);
rootbuffer = SpGistNewBuffer(index);
Assert(BufferGetBlockNumber(metabuffer) == SPGIST_METAPAGE_BLKNO);
Assert(BufferGetBlockNumber(rootbuffer) == SPGIST_HEAD_BLKNO);
START_CRIT_SECTION();
SpGistInitMetapage(BufferGetPage(metabuffer));
MarkBufferDirty(metabuffer);
SpGistInitBuffer(rootbuffer, SPGIST_LEAF);
MarkBufferDirty(rootbuffer);
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
XLogRecData rdata;
/* WAL data is just the relfilenode */
rdata.data = (char *) &(index->rd_node);
rdata.len = sizeof(RelFileNode);
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_CREATE_INDEX, &rdata);
PageSetLSN(BufferGetPage(metabuffer), recptr);
PageSetTLI(BufferGetPage(metabuffer), ThisTimeLineID);
PageSetLSN(BufferGetPage(rootbuffer), recptr);
PageSetTLI(BufferGetPage(rootbuffer), ThisTimeLineID);
}
END_CRIT_SECTION();
UnlockReleaseBuffer(metabuffer);
UnlockReleaseBuffer(rootbuffer);
/*
* Now insert all the heap data into the index
*/
initSpGistState(&buildstate.spgstate, index);
buildstate.spgstate.isBuild = true;
buildstate.tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
"SP-GiST build temporary context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
reltuples = IndexBuildHeapScan(heap, index, indexInfo, true,
spgistBuildCallback, (void *) &buildstate);
MemoryContextDelete(buildstate.tmpCtx);
SpGistUpdateMetaPage(index);
result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
result->heap_tuples = result->index_tuples = reltuples;
PG_RETURN_POINTER(result);
}
/*
* Build an SP-GiST index.
*/
Datum
spgbuild(PG_FUNCTION_ARGS)
{
Relation heap = (Relation) PG_GETARG_POINTER(0);
Relation index = (Relation) PG_GETARG_POINTER(1);
IndexInfo *indexInfo = (IndexInfo *) PG_GETARG_POINTER(2);
IndexBuildResult *result;
double reltuples;
SpGistBuildState buildstate;
Buffer metabuffer,
rootbuffer,
nullbuffer;
if (RelationGetNumberOfBlocks(index) != 0)
elog(ERROR, "index \"%s\" already contains data",
RelationGetRelationName(index));
/*
* Initialize the meta page and root pages
*/
metabuffer = SpGistNewBuffer(index);
rootbuffer = SpGistNewBuffer(index);
nullbuffer = SpGistNewBuffer(index);
Assert(BufferGetBlockNumber(metabuffer) == SPGIST_METAPAGE_BLKNO);
Assert(BufferGetBlockNumber(rootbuffer) == SPGIST_ROOT_BLKNO);
Assert(BufferGetBlockNumber(nullbuffer) == SPGIST_NULL_BLKNO);
START_CRIT_SECTION();
SpGistInitMetapage(BufferGetPage(metabuffer));
MarkBufferDirty(metabuffer);
SpGistInitBuffer(rootbuffer, SPGIST_LEAF);
MarkBufferDirty(rootbuffer);
SpGistInitBuffer(nullbuffer, SPGIST_LEAF | SPGIST_NULLS);
MarkBufferDirty(nullbuffer);
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
XLogBeginInsert();
/*
* Replay will re-initialize the pages, so don't take full pages
* images. No other data to log.
*/
XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT);
XLogRegisterBuffer(1, rootbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
XLogRegisterBuffer(2, nullbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_CREATE_INDEX);
PageSetLSN(BufferGetPage(metabuffer), recptr);
PageSetLSN(BufferGetPage(rootbuffer), recptr);
PageSetLSN(BufferGetPage(nullbuffer), recptr);
}
END_CRIT_SECTION();
UnlockReleaseBuffer(metabuffer);
UnlockReleaseBuffer(rootbuffer);
UnlockReleaseBuffer(nullbuffer);
/*
* Now insert all the heap data into the index
*/
initSpGistState(&buildstate.spgstate, index);
buildstate.spgstate.isBuild = true;
buildstate.tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
"SP-GiST build temporary context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
reltuples = IndexBuildHeapScan(heap, index, indexInfo, true,
spgistBuildCallback, (void *) &buildstate);
MemoryContextDelete(buildstate.tmpCtx);
SpGistUpdateMetaPage(index);
result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
result->heap_tuples = result->index_tuples = reltuples;
PG_RETURN_POINTER(result);
}
