/*
* Update lastUsedPages cache when done modifying a page.
*
* We update the appropriate cache entry if it already contained this page
* (its freeSpace is likely obsolete), or if this page has more space than
* whatever we had cached.
*/
void
SpGistSetLastUsedPage(Relation index, Buffer buffer)
{
SpGistCache *cache = spgGetCache(index);
SpGistLastUsedPage *lup;
int freeSpace;
Page page = BufferGetPage(buffer);
BlockNumber blkno = BufferGetBlockNumber(buffer);
int flags;
/* Never enter fixed pages (root pages) in cache, though */
if (SpGistBlockIsFixed(blkno))
return;
if (SpGistPageIsLeaf(page))
flags = GBUF_LEAF;
else
flags = GBUF_INNER_PARITY(blkno);
if (SpGistPageStoresNulls(page))
flags |= GBUF_NULLS;
lup = GET_LUP(cache, flags);
freeSpace = PageGetExactFreeSpace(page);
if (lup->blkno == InvalidBlockNumber || lup->blkno == blkno ||
lup->freeSpace < freeSpace)
{
lup->blkno = blkno;
lup->freeSpace = freeSpace;
}
}
/*
* Update lastUsedPages cache when done modifying a page.
*
* We update the appropriate cache entry if it already contained this page
* (its freeSpace is likely obsolete), or if this page has more space than
* whatever we had cached.
*/
void
SpGistSetLastUsedPage(Relation index, Buffer buffer)
{
SpGistCache *cache = spgGetCache(index);
SpGistLastUsedPage *lup;
int freeSpace;
Page page = BufferGetPage(buffer);
BlockNumber blkno = BufferGetBlockNumber(buffer);
int flags;
/* Never enter the root page in cache, though */
if (blkno == SPGIST_HEAD_BLKNO)
return;
if (SpGistPageIsLeaf(page))
flags = GBUF_LEAF;
else
flags = GBUF_INNER_PARITY(blkno);
lup = GET_LUP(cache, flags);
freeSpace = PageGetExactFreeSpace(page);
if (lup->blkno == InvalidBlockNumber || lup->blkno == blkno ||
lup->freeSpace < freeSpace)
{
lup->blkno = blkno;
lup->freeSpace = freeSpace;
}
}
Datum
spgstat(PG_FUNCTION_ARGS)
{
text *name=PG_GETARG_TEXT_P(0);
char *relname=text_to_cstring(name);
RangeVar *relvar;
Relation index;
List *relname_list;
Oid relOid;
BlockNumber blkno = SPGIST_HEAD_BLKNO;
BlockNumber totalPages = 0,
innerPages = 0,
emptyPages = 0;
double usedSpace = 0.0;
char res[1024];
int bufferSize = -1;
int64 innerTuples = 0,
leafTuples = 0;
relname_list = stringToQualifiedNameList(relname);
relvar = makeRangeVarFromNameList(relname_list);
relOid = RangeVarGetRelid(relvar, false);
index = index_open(relOid, AccessExclusiveLock);
if ( index->rd_am == NULL )
elog(ERROR, "Relation %s.%s is not an index",
get_namespace_name(RelationGetNamespace(index)),
RelationGetRelationName(index) );
totalPages = RelationGetNumberOfBlocks(index);
for(blkno=SPGIST_HEAD_BLKNO; blkno<totalPages; blkno++)
{
Buffer buffer;
Page page;
buffer = ReadBuffer(index, blkno);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = BufferGetPage(buffer);
if (SpGistPageIsLeaf(page))
{
leafTuples += SpGistPageGetMaxOffset(page);
}
else
{
innerPages++;
innerTuples += SpGistPageGetMaxOffset(page);
}
if (bufferSize < 0)
bufferSize = BufferGetPageSize(buffer) - MAXALIGN(sizeof(SpGistPageOpaqueData)) -
SizeOfPageHeaderData;
usedSpace += bufferSize - (PageGetFreeSpace(page) + sizeof(ItemIdData));
if (PageGetFreeSpace(page) + sizeof(ItemIdData) == bufferSize)
emptyPages++;
UnlockReleaseBuffer(buffer);
}
index_close(index, AccessExclusiveLock);
totalPages--; /* metapage */
snprintf(res, sizeof(res),
"totalPages: %u\n"
"innerPages: %u\n"
"leafPages: %u\n"
"emptyPages: %u\n"
"usedSpace: %.2f kbytes\n"
"freeSpace: %.2f kbytes\n"
"fillRatio: %.2f%c\n"
"leafTuples: %lld\n"
"innerTuples: %lld",
totalPages, innerPages, totalPages - innerPages, emptyPages,
usedSpace / 1024.0,
(( (double) bufferSize ) * ( (double) totalPages ) - usedSpace) / 1024,
100.0 * ( usedSpace / (( (double) bufferSize ) * ( (double) totalPages )) ),
'%',
leafTuples, innerTuples
);
PG_RETURN_TEXT_P(CStringGetTextDatum(res));
}
/*
* Process the pending-TID list between pages of the main scan
*/
static void
spgprocesspending(spgBulkDeleteState *bds)
{
Relation index = bds->info->index;
spgVacPendingItem *pitem;
spgVacPendingItem *nitem;
BlockNumber blkno;
Buffer buffer;
Page page;
for (pitem = bds->pendingList; pitem != NULL; pitem = pitem->next)
{
if (pitem->done)
continue; /* ignore already-done items */
/* call vacuum_delay_point while not holding any buffer lock */
vacuum_delay_point();
/* examine the referenced page */
blkno = ItemPointerGetBlockNumber(&pitem->tid);
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, bds->info->strategy);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew(page) || SpGistPageIsDeleted(page))
{
/* Probably shouldn't happen, but ignore it */
}
else if (SpGistPageIsLeaf(page))
{
if (SpGistBlockIsRoot(blkno))
{
/* this should definitely not happen */
elog(ERROR, "redirection leads to root page of index \"%s\"",
RelationGetRelationName(index));
}
/* deal with any deletable tuples */
vacuumLeafPage(bds, index, buffer, true);
/* might as well do this while we are here */
vacuumRedirectAndPlaceholder(index, buffer);
SpGistSetLastUsedPage(index, buffer);
/*
* We can mark as done not only this item, but any later ones
* pointing at the same page, since we vacuumed the whole page.
*/
pitem->done = true;
for (nitem = pitem->next; nitem != NULL; nitem = nitem->next)
{
if (ItemPointerGetBlockNumber(&nitem->tid) == blkno)
nitem->done = true;
}
}
else
{
/*
* On an inner page, visit the referenced inner tuple and add all
* its downlinks to the pending list. We might have pending items
* for more than one inner tuple on the same page (in fact this is
* pretty likely given the way space allocation works), so get
* them all while we are here.
*/
for (nitem = pitem; nitem != NULL; nitem = nitem->next)
{
if (nitem->done)
continue;
if (ItemPointerGetBlockNumber(&nitem->tid) == blkno)
{
OffsetNumber offset;
SpGistInnerTuple innerTuple;
offset = ItemPointerGetOffsetNumber(&nitem->tid);
innerTuple = (SpGistInnerTuple) PageGetItem(page,
PageGetItemId(page, offset));
if (innerTuple->tupstate == SPGIST_LIVE)
{
SpGistNodeTuple node;
int i;
SGITITERATE(innerTuple, i, node)
{
if (ItemPointerIsValid(&node->t_tid))
spgAddPendingTID(bds, &node->t_tid);
}
}
else if (innerTuple->tupstate == SPGIST_REDIRECT)
{
/* transfer attention to redirect point */
spgAddPendingTID(bds,
&((SpGistDeadTuple) innerTuple)->pointer);
}
else
elog(ERROR, "unexpected SPGiST tuple state: %d",
innerTuple->tupstate);
nitem->done = true;
}
}
/*
* Process one page during a bulkdelete scan
*/
static void
spgvacuumpage(spgBulkDeleteState *bds, BlockNumber blkno)
{
Relation index = bds->info->index;
Buffer buffer;
Page page;
/* call vacuum_delay_point while not holding any buffer lock */
vacuum_delay_point();
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, bds->info->strategy);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew(page))
{
/*
* We found an all-zero page, which could happen if the database
* crashed just after extending the file. Initialize and recycle it.
*/
SpGistInitBuffer(buffer, 0);
SpGistPageSetDeleted(page);
/* We don't bother to WAL-log this action; easy to redo */
MarkBufferDirty(buffer);
}
else if (SpGistPageIsDeleted(page))
{
/* nothing to do */
}
else if (SpGistPageIsLeaf(page))
{
if (SpGistBlockIsRoot(blkno))
{
vacuumLeafRoot(bds, index, buffer);
/* no need for vacuumRedirectAndPlaceholder */
}
else
{
vacuumLeafPage(bds, index, buffer, false);
vacuumRedirectAndPlaceholder(index, buffer);
}
}
else
{
/* inner page */
vacuumRedirectAndPlaceholder(index, buffer);
}
/*
* The root pages must never be deleted, nor marked as available in FSM,
* because we don't want them ever returned by a search for a place to put
* a new tuple. Otherwise, check for empty/deletable page, and make sure
* FSM knows about it.
*/
if (!SpGistBlockIsRoot(blkno))
{
/* If page is now empty, mark it deleted */
if (PageIsEmpty(page) && !SpGistPageIsDeleted(page))
{
SpGistPageSetDeleted(page);
/* We don't bother to WAL-log this action; easy to redo */
MarkBufferDirty(buffer);
}
if (SpGistPageIsDeleted(page))
{
RecordFreeIndexPage(index, blkno);
bds->stats->pages_deleted++;
}
else
bds->lastFilledBlock = blkno;
}
SpGistSetLastUsedPage(index, buffer);
UnlockReleaseBuffer(buffer);
}
/*
* Get a buffer of the type and parity specified by flags, having at least
* as much free space as indicated by needSpace. We use the lastUsedPages
* cache to assign the same buffer previously requested when possible.
* The returned buffer is already pinned and exclusive-locked.
*
* *isNew is set true if the page was initialized here, false if it was
* already valid.
*/
Buffer
SpGistGetBuffer(Relation index, int flags, int needSpace, bool *isNew)
{
SpGistCache *cache = spgGetCache(index);
SpGistLastUsedPage *lup;
/* Bail out if even an empty page wouldn't meet the demand */
if (needSpace > SPGIST_PAGE_CAPACITY)
elog(ERROR, "desired SPGiST tuple size is too big");
/*
* If possible, increase the space request to include relation's
* fillfactor. This ensures that when we add unrelated tuples to a page,
* we try to keep 100-fillfactor% available for adding tuples that are
* related to the ones already on it. But fillfactor mustn't cause an
* error for requests that would otherwise be legal.
*/
needSpace += RelationGetTargetPageFreeSpace(index,
SPGIST_DEFAULT_FILLFACTOR);
needSpace = Min(needSpace, SPGIST_PAGE_CAPACITY);
/* Get the cache entry for this flags setting */
lup = GET_LUP(cache, flags);
/* If we have nothing cached, just turn it over to allocNewBuffer */
if (lup->blkno == InvalidBlockNumber)
{
*isNew = true;
return allocNewBuffer(index, flags);
}
/* fixed pages should never be in cache */
Assert(!SpGistBlockIsFixed(lup->blkno));
/* If cached freeSpace isn't enough, don't bother looking at the page */
if (lup->freeSpace >= needSpace)
{
Buffer buffer;
Page page;
buffer = ReadBuffer(index, lup->blkno);
if (!ConditionalLockBuffer(buffer))
{
/*
* buffer is locked by another process, so return a new buffer
*/
ReleaseBuffer(buffer);
*isNew = true;
return allocNewBuffer(index, flags);
}
page = BufferGetPage(buffer);
if (PageIsNew(page) || SpGistPageIsDeleted(page) || PageIsEmpty(page))
{
/* OK to initialize the page */
uint16 pageflags = 0;
if (GBUF_REQ_LEAF(flags))
pageflags |= SPGIST_LEAF;
if (GBUF_REQ_NULLS(flags))
pageflags |= SPGIST_NULLS;
SpGistInitBuffer(buffer, pageflags);
lup->freeSpace = PageGetExactFreeSpace(page) - needSpace;
*isNew = true;
return buffer;
}
/*
* Check that page is of right type and has enough space. We must
* recheck this since our cache isn't necessarily up to date.
*/
if ((GBUF_REQ_LEAF(flags) ? SpGistPageIsLeaf(page) : !SpGistPageIsLeaf(page)) &&
(GBUF_REQ_NULLS(flags) ? SpGistPageStoresNulls(page) : !SpGistPageStoresNulls(page)))
{
int freeSpace = PageGetExactFreeSpace(page);
if (freeSpace >= needSpace)
{
/* Success, update freespace info and return the buffer */
lup->freeSpace = freeSpace - needSpace;
*isNew = false;
return buffer;
}
}
/*
* fallback to allocation of new buffer
*/
UnlockReleaseBuffer(buffer);
}
/* No success with cache, so return a new buffer */
*isNew = true;
return allocNewBuffer(index, flags);
}