/*
* Execute the index scan.
*
* This works by reading index TIDs from the revmap, and obtaining the index
* tuples pointed to by them; the summary values in the index tuples are
* compared to the scan keys. We return into the TID bitmap all the pages in
* ranges corresponding to index tuples that match the scan keys.
*
* If a TID from the revmap is read as InvalidTID, we know that range is
* unsummarized. Pages in those ranges need to be returned regardless of scan
* keys.
*/
int64
bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
{
Relation idxRel = scan->indexRelation;
Buffer buf = InvalidBuffer;
BrinDesc *bdesc;
Oid heapOid;
Relation heapRel;
BrinOpaque *opaque;
BlockNumber nblocks;
BlockNumber heapBlk;
int totalpages = 0;
FmgrInfo *consistentFn;
MemoryContext oldcxt;
MemoryContext perRangeCxt;
opaque = (BrinOpaque *) scan->opaque;
bdesc = opaque->bo_bdesc;
pgstat_count_index_scan(idxRel);
/*
* We need to know the size of the table so that we know how long to
* iterate on the revmap.
*/
heapOid = IndexGetRelation(RelationGetRelid(idxRel), false);
heapRel = heap_open(heapOid, AccessShareLock);
nblocks = RelationGetNumberOfBlocks(heapRel);
heap_close(heapRel, AccessShareLock);
/*
* Make room for the consistent support procedures of indexed columns. We
* don't look them up here; we do that lazily the first time we see a scan
* key reference each of them. We rely on zeroing fn_oid to InvalidOid.
*/
consistentFn = palloc0(sizeof(FmgrInfo) * bdesc->bd_tupdesc->natts);
/*
* Setup and use a per-range memory context, which is reset every time we
* loop below. This avoids having to free the tuples within the loop.
*/
perRangeCxt = AllocSetContextCreate(CurrentMemoryContext,
"bringetbitmap cxt",
ALLOCSET_DEFAULT_SIZES);
oldcxt = MemoryContextSwitchTo(perRangeCxt);
/*
* Now scan the revmap. We start by querying for heap page 0,
* incrementing by the number of pages per range; this gives us a full
* view of the table.
*/
for (heapBlk = 0; heapBlk < nblocks; heapBlk += opaque->bo_pagesPerRange)
{
bool addrange;
BrinTuple *tup;
OffsetNumber off;
Size size;
CHECK_FOR_INTERRUPTS();
MemoryContextResetAndDeleteChildren(perRangeCxt);
tup = brinGetTupleForHeapBlock(opaque->bo_rmAccess, heapBlk, &buf,
&off, &size, BUFFER_LOCK_SHARE,
scan->xs_snapshot);
if (tup)
{
tup = brin_copy_tuple(tup, size);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
/*
* For page ranges with no indexed tuple, we must return the whole
* range; otherwise, compare it to the scan keys.
*/
if (tup == NULL)
{
addrange = true;
}
else
{
BrinMemTuple *dtup;
dtup = brin_deform_tuple(bdesc, tup);
if (dtup->bt_placeholder)
{
/*
* Placeholder tuples are always returned, regardless of the
* values stored in them.
*/
addrange = true;
}
else
{
int keyno;
/*
* Compare scan keys with summary values stored for the range.
* If scan keys are matched, the page range must be added to
* the bitmap. We initially assume the range needs to be
* added; in particular this serves the case where there are
* no keys.
*/
addrange = true;
for (keyno = 0; keyno < scan->numberOfKeys; keyno++)
{
ScanKey key = &scan->keyData[keyno];
AttrNumber keyattno = key->sk_attno;
BrinValues *bval = &dtup->bt_columns[keyattno - 1];
Datum add;
/*
* The collation of the scan key must match the collation
* used in the index column (but only if the search is not
* IS NULL/ IS NOT NULL). Otherwise we shouldn't be using
* this index ...
*/
Assert((key->sk_flags & SK_ISNULL) ||
(key->sk_collation ==
bdesc->bd_tupdesc->attrs[keyattno - 1]->attcollation));
/* First time this column? look up consistent function */
if (consistentFn[keyattno - 1].fn_oid == InvalidOid)
{
FmgrInfo *tmp;
tmp = index_getprocinfo(idxRel, keyattno,
BRIN_PROCNUM_CONSISTENT);
fmgr_info_copy(&consistentFn[keyattno - 1], tmp,
CurrentMemoryContext);
}
/*
* Check whether the scan key is consistent with the page
* range values; if so, have the pages in the range added
* to the output bitmap.
*
* When there are multiple scan keys, failure to meet the
* criteria for a single one of them is enough to discard
* the range as a whole, so break out of the loop as soon
* as a false return value is obtained.
*/
add = FunctionCall3Coll(&consistentFn[keyattno - 1],
key->sk_collation,
PointerGetDatum(bdesc),
PointerGetDatum(bval),
PointerGetDatum(key));
addrange = DatumGetBool(add);
if (!addrange)
break;
}
}
}
/* add the pages in the range to the output bitmap, if needed */
if (addrange)
{
BlockNumber pageno;
for (pageno = heapBlk;
pageno <= heapBlk + opaque->bo_pagesPerRange - 1;
pageno++)
{
MemoryContextSwitchTo(oldcxt);
tbm_add_page(tbm, pageno);
totalpages++;
MemoryContextSwitchTo(perRangeCxt);
}
}
}
MemoryContextSwitchTo(oldcxt);
MemoryContextDelete(perRangeCxt);
if (buf != InvalidBuffer)
ReleaseBuffer(buf);
/*
* XXX We have an approximation of the number of *pages* that our scan
* returns, but we don't have a precise idea of the number of heap tuples
* involved.
*/
return totalpages * 10;
}
/*
* Summarize the given page range of the given index.
*
* This routine can run in parallel with insertions into the heap. To avoid
* missing those values from the summary tuple, we first insert a placeholder
* index tuple into the index, then execute the heap scan; transactions
* concurrent with the scan update the placeholder tuple. After the scan, we
* union the placeholder tuple with the one computed by this routine. The
* update of the index value happens in a loop, so that if somebody updates
* the placeholder tuple after we read it, we detect the case and try again.
* This ensures that the concurrently inserted tuples are not lost.
*/
static void
summarize_range(IndexInfo *indexInfo, BrinBuildState *state, Relation heapRel,
BlockNumber heapBlk, BlockNumber heapNumBlks)
{
Buffer phbuf;
BrinTuple *phtup;
Size phsz;
OffsetNumber offset;
BlockNumber scanNumBlks;
/*
* Insert the placeholder tuple
*/
phbuf = InvalidBuffer;
phtup = brin_form_placeholder_tuple(state->bs_bdesc, heapBlk, &phsz);
offset = brin_doinsert(state->bs_irel, state->bs_pagesPerRange,
state->bs_rmAccess, &phbuf,
heapBlk, phtup, phsz);
/*
* Execute the partial heap scan covering the heap blocks in the specified
* page range, summarizing the heap tuples in it. This scan stops just
* short of brinbuildCallback creating the new index entry.
*
* Note that it is critical we use the "any visible" mode of
* IndexBuildHeapRangeScan here: otherwise, we would miss tuples inserted
* by transactions that are still in progress, among other corner cases.
*/
state->bs_currRangeStart = heapBlk;
scanNumBlks = heapBlk + state->bs_pagesPerRange <= heapNumBlks ?
state->bs_pagesPerRange : heapNumBlks - heapBlk;
IndexBuildHeapRangeScan(heapRel, state->bs_irel, indexInfo, false, true,
heapBlk, scanNumBlks,
brinbuildCallback, (void *) state);
/*
* Now we update the values obtained by the scan with the placeholder
* tuple. We do this in a loop which only terminates if we're able to
* update the placeholder tuple successfully; if we are not, this means
* somebody else modified the placeholder tuple after we read it.
*/
for (;;)
{
BrinTuple *newtup;
Size newsize;
bool didupdate;
bool samepage;
CHECK_FOR_INTERRUPTS();
/*
* Update the summary tuple and try to update.
*/
newtup = brin_form_tuple(state->bs_bdesc,
heapBlk, state->bs_dtuple, &newsize);
samepage = brin_can_do_samepage_update(phbuf, phsz, newsize);
didupdate =
brin_doupdate(state->bs_irel, state->bs_pagesPerRange,
state->bs_rmAccess, heapBlk, phbuf, offset,
phtup, phsz, newtup, newsize, samepage);
brin_free_tuple(phtup);
brin_free_tuple(newtup);
/* If the update succeeded, we're done. */
if (didupdate)
break;
/*
* If the update didn't work, it might be because somebody updated the
* placeholder tuple concurrently. Extract the new version, union it
* with the values we have from the scan, and start over. (There are
* other reasons for the update to fail, but it's simple to treat them
* the same.)
*/
phtup = brinGetTupleForHeapBlock(state->bs_rmAccess, heapBlk, &phbuf,
&offset, &phsz, BUFFER_LOCK_SHARE,
NULL);
/* the placeholder tuple must exist */
if (phtup == NULL)
elog(ERROR, "missing placeholder tuple");
phtup = brin_copy_tuple(phtup, phsz);
LockBuffer(phbuf, BUFFER_LOCK_UNLOCK);
/* merge it into the tuple from the heap scan */
union_tuples(state->bs_bdesc, state->bs_dtuple, phtup);
}
ReleaseBuffer(phbuf);
}
/*
* Scan a complete BRIN index, and summarize each page range that's not already
* summarized. The index and heap must have been locked by caller in at
* least ShareUpdateExclusiveLock mode.
*
* For each new index tuple inserted, *numSummarized (if not NULL) is
* incremented; for each existing tuple, *numExisting (if not NULL) is
* incremented.
*/
static void
brinsummarize(Relation index, Relation heapRel, double *numSummarized,
double *numExisting)
{
BrinRevmap *revmap;
BrinBuildState *state = NULL;
IndexInfo *indexInfo = NULL;
BlockNumber heapNumBlocks;
BlockNumber heapBlk;
BlockNumber pagesPerRange;
Buffer buf;
revmap = brinRevmapInitialize(index, &pagesPerRange, NULL);
/*
* Scan the revmap to find unsummarized items.
*/
buf = InvalidBuffer;
heapNumBlocks = RelationGetNumberOfBlocks(heapRel);
for (heapBlk = 0; heapBlk < heapNumBlocks; heapBlk += pagesPerRange)
{
BrinTuple *tup;
OffsetNumber off;
CHECK_FOR_INTERRUPTS();
tup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off, NULL,
BUFFER_LOCK_SHARE, NULL);
if (tup == NULL)
{
/* no revmap entry for this heap range. Summarize it. */
if (state == NULL)
{
/* first time through */
Assert(!indexInfo);
state = initialize_brin_buildstate(index, revmap,
pagesPerRange);
indexInfo = BuildIndexInfo(index);
}
summarize_range(indexInfo, state, heapRel, heapBlk, heapNumBlocks);
/* and re-initialize state for the next range */
brin_memtuple_initialize(state->bs_dtuple, state->bs_bdesc);
if (numSummarized)
*numSummarized += 1.0;
}
else
{
if (numExisting)
*numExisting += 1.0;
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
}
if (BufferIsValid(buf))
ReleaseBuffer(buf);
/* free resources */
brinRevmapTerminate(revmap);
if (state)
{
terminate_brin_buildstate(state);
pfree(indexInfo);
}
}
/*
* A tuple in the heap is being inserted. To keep a brin index up to date,
* we need to obtain the relevant index tuple and compare its stored values
* with those of the new tuple. If the tuple values are not consistent with
* the summary tuple, we need to update the index tuple.
*
* If the range is not currently summarized (i.e. the revmap returns NULL for
* it), there's nothing to do.
*/
bool
brininsert(Relation idxRel, Datum *values, bool *nulls,
ItemPointer heaptid, Relation heapRel,
IndexUniqueCheck checkUnique)
{
BlockNumber pagesPerRange;
BrinDesc *bdesc = NULL;
BrinRevmap *revmap;
Buffer buf = InvalidBuffer;
MemoryContext tupcxt = NULL;
MemoryContext oldcxt = NULL;
revmap = brinRevmapInitialize(idxRel, &pagesPerRange, NULL);
for (;;)
{
bool need_insert = false;
OffsetNumber off;
BrinTuple *brtup;
BrinMemTuple *dtup;
BlockNumber heapBlk;
int keyno;
CHECK_FOR_INTERRUPTS();
heapBlk = ItemPointerGetBlockNumber(heaptid);
/* normalize the block number to be the first block in the range */
heapBlk = (heapBlk / pagesPerRange) * pagesPerRange;
brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off, NULL,
BUFFER_LOCK_SHARE, NULL);
/* if range is unsummarized, there's nothing to do */
if (!brtup)
break;
/* First time through? */
if (bdesc == NULL)
{
bdesc = brin_build_desc(idxRel);
tupcxt = AllocSetContextCreate(CurrentMemoryContext,
"brininsert cxt",
ALLOCSET_DEFAULT_SIZES);
oldcxt = MemoryContextSwitchTo(tupcxt);
}
dtup = brin_deform_tuple(bdesc, brtup);
/*
* Compare the key values of the new tuple to the stored index values;
* our deformed tuple will get updated if the new tuple doesn't fit
* the original range (note this means we can't break out of the loop
* early). Make a note of whether this happens, so that we know to
* insert the modified tuple later.
*/
for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
{
Datum result;
BrinValues *bval;
FmgrInfo *addValue;
bval = &dtup->bt_columns[keyno];
addValue = index_getprocinfo(idxRel, keyno + 1,
BRIN_PROCNUM_ADDVALUE);
result = FunctionCall4Coll(addValue,
idxRel->rd_indcollation[keyno],
PointerGetDatum(bdesc),
PointerGetDatum(bval),
values[keyno],
nulls[keyno]);
/* if that returned true, we need to insert the updated tuple */
need_insert |= DatumGetBool(result);
}
if (!need_insert)
{
/*
* The tuple is consistent with the new values, so there's nothing
* to do.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
else
{
Page page = BufferGetPage(buf);
ItemId lp = PageGetItemId(page, off);
Size origsz;
BrinTuple *origtup;
Size newsz;
BrinTuple *newtup;
bool samepage;
/*
* Make a copy of the old tuple, so that we can compare it after
* re-acquiring the lock.
*/
origsz = ItemIdGetLength(lp);
origtup = brin_copy_tuple(brtup, origsz);
/*
* Before releasing the lock, check if we can attempt a same-page
* update. Another process could insert a tuple concurrently in
* the same page though, so downstream we must be prepared to cope
* if this turns out to not be possible after all.
*/
newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
samepage = brin_can_do_samepage_update(buf, origsz, newsz);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/*
* Try to update the tuple. If this doesn't work for whatever
* reason, we need to restart from the top; the revmap might be
* pointing at a different tuple for this block now, so we need to
* recompute to ensure both our new heap tuple and the other
* inserter's are covered by the combined tuple. It might be that
* we don't need to update at all.
*/
if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
buf, off, origtup, origsz, newtup, newsz,
samepage))
{
/* no luck; start over */
MemoryContextResetAndDeleteChildren(tupcxt);
continue;
}
}
/* success! */
break;
}
brinRevmapTerminate(revmap);
if (BufferIsValid(buf))
ReleaseBuffer(buf);
if (bdesc != NULL)
{
brin_free_desc(bdesc);
MemoryContextSwitchTo(oldcxt);
MemoryContextDelete(tupcxt);
}
return false;
}
/*
* On the given BRIN index, summarize the heap page range that corresponds
* to the heap block number given.
*
* This routine can run in parallel with insertions into the heap. To avoid
* missing those values from the summary tuple, we first insert a placeholder
* index tuple into the index, then execute the heap scan; transactions
* concurrent with the scan update the placeholder tuple. After the scan, we
* union the placeholder tuple with the one computed by this routine. The
* update of the index value happens in a loop, so that if somebody updates
* the placeholder tuple after we read it, we detect the case and try again.
* This ensures that the concurrently inserted tuples are not lost.
*
* A further corner case is this routine being asked to summarize the partial
* range at the end of the table. heapNumBlocks is the (possibly outdated)
* table size; if we notice that the requested range lies beyond that size,
* we re-compute the table size after inserting the placeholder tuple, to
* avoid missing pages that were appended recently.
*/
static void
summarize_range(IndexInfo *indexInfo, BrinBuildState *state, Relation heapRel,
BlockNumber heapBlk, BlockNumber heapNumBlks)
{
Buffer phbuf;
BrinTuple *phtup;
Size phsz;
OffsetNumber offset;
BlockNumber scanNumBlks;
/*
* Insert the placeholder tuple
*/
phbuf = InvalidBuffer;
phtup = brin_form_placeholder_tuple(state->bs_bdesc, heapBlk, &phsz);
offset = brin_doinsert(state->bs_irel, state->bs_pagesPerRange,
state->bs_rmAccess, &phbuf,
heapBlk, phtup, phsz);
/*
* Compute range end. We hold ShareUpdateExclusive lock on table, so it
* cannot shrink concurrently (but it can grow).
*/
Assert(heapBlk % state->bs_pagesPerRange == 0);
if (heapBlk + state->bs_pagesPerRange > heapNumBlks)
{
/*
* If we're asked to scan what we believe to be the final range on the
* table (i.e. a range that might be partial) we need to recompute our
* idea of what the latest page is after inserting the placeholder
* tuple. Anyone that grows the table later will update the
* placeholder tuple, so it doesn't matter that we won't scan these
* pages ourselves. Careful: the table might have been extended
* beyond the current range, so clamp our result.
*
* Fortunately, this should occur infrequently.
*/
scanNumBlks = Min(RelationGetNumberOfBlocks(heapRel) - heapBlk,
state->bs_pagesPerRange);
}
else
{
/* Easy case: range is known to be complete */
scanNumBlks = state->bs_pagesPerRange;
}
/*
* Execute the partial heap scan covering the heap blocks in the specified
* page range, summarizing the heap tuples in it. This scan stops just
* short of brinbuildCallback creating the new index entry.
*
* Note that it is critical we use the "any visible" mode of
* IndexBuildHeapRangeScan here: otherwise, we would miss tuples inserted
* by transactions that are still in progress, among other corner cases.
*/
state->bs_currRangeStart = heapBlk;
IndexBuildHeapRangeScan(heapRel, state->bs_irel, indexInfo, false, true,
heapBlk, scanNumBlks,
brinbuildCallback, (void *) state);
/*
* Now we update the values obtained by the scan with the placeholder
* tuple. We do this in a loop which only terminates if we're able to
* update the placeholder tuple successfully; if we are not, this means
* somebody else modified the placeholder tuple after we read it.
*/
for (;;)
{
BrinTuple *newtup;
Size newsize;
bool didupdate;
bool samepage;
CHECK_FOR_INTERRUPTS();
/*
* Update the summary tuple and try to update.
*/
newtup = brin_form_tuple(state->bs_bdesc,
heapBlk, state->bs_dtuple, &newsize);
samepage = brin_can_do_samepage_update(phbuf, phsz, newsize);
didupdate =
brin_doupdate(state->bs_irel, state->bs_pagesPerRange,
state->bs_rmAccess, heapBlk, phbuf, offset,
phtup, phsz, newtup, newsize, samepage);
brin_free_tuple(phtup);
brin_free_tuple(newtup);
/* If the update succeeded, we're done. */
if (didupdate)
break;
/*
* If the update didn't work, it might be because somebody updated the
* placeholder tuple concurrently. Extract the new version, union it
* with the values we have from the scan, and start over. (There are
* other reasons for the update to fail, but it's simple to treat them
* the same.)
*/
phtup = brinGetTupleForHeapBlock(state->bs_rmAccess, heapBlk, &phbuf,
&offset, &phsz, BUFFER_LOCK_SHARE,
NULL);
/* the placeholder tuple must exist */
if (phtup == NULL)
elog(ERROR, "missing placeholder tuple");
phtup = brin_copy_tuple(phtup, phsz);
LockBuffer(phbuf, BUFFER_LOCK_UNLOCK);
/* merge it into the tuple from the heap scan */
union_tuples(state->bs_bdesc, state->bs_dtuple, phtup);
}
ReleaseBuffer(phbuf);
}
/*
* A tuple in the heap is being inserted. To keep a brin index up to date,
* we need to obtain the relevant index tuple and compare its stored values
* with those of the new tuple. If the tuple values are not consistent with
* the summary tuple, we need to update the index tuple.
*
* If the range is not currently summarized (i.e. the revmap returns NULL for
* it), there's nothing to do.
*/
Datum
brininsert(PG_FUNCTION_ARGS)
{
Relation idxRel = (Relation) PG_GETARG_POINTER(0);
Datum *values = (Datum *) PG_GETARG_POINTER(1);
bool *nulls = (bool *) PG_GETARG_POINTER(2);
ItemPointer heaptid = (ItemPointer) PG_GETARG_POINTER(3);
/* we ignore the rest of our arguments */
BlockNumber pagesPerRange;
BrinDesc *bdesc = NULL;
BrinRevmap *revmap;
Buffer buf = InvalidBuffer;
MemoryContext tupcxt = NULL;
MemoryContext oldcxt = NULL;
revmap = brinRevmapInitialize(idxRel, &pagesPerRange);
for (;;)
{
bool need_insert = false;
OffsetNumber off;
BrinTuple *brtup;
BrinMemTuple *dtup;
BlockNumber heapBlk;
int keyno;
#ifdef USE_ASSERT_CHECKING
BrinTuple *tmptup;
BrinMemTuple *tmpdtup;
Size tmpsiz;
#endif
CHECK_FOR_INTERRUPTS();
heapBlk = ItemPointerGetBlockNumber(heaptid);
/* normalize the block number to be the first block in the range */
heapBlk = (heapBlk / pagesPerRange) * pagesPerRange;
brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off, NULL,
BUFFER_LOCK_SHARE);
/* if range is unsummarized, there's nothing to do */
if (!brtup)
break;
/* First time through? */
if (bdesc == NULL)
{
bdesc = brin_build_desc(idxRel);
tupcxt = AllocSetContextCreate(CurrentMemoryContext,
"brininsert cxt",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
oldcxt = MemoryContextSwitchTo(tupcxt);
}
dtup = brin_deform_tuple(bdesc, brtup);
#ifdef USE_ASSERT_CHECKING
{
/*
* When assertions are enabled, we use this as an opportunity to
* test the "union" method, which would otherwise be used very
* rarely: first create a placeholder tuple, and addValue the
* value we just got into it. Then union the existing index tuple
* with the updated placeholder tuple. The tuple resulting from
* that union should be identical to the one resulting from the
* regular operation (straight addValue) below.
*
* Here we create the tuple to compare with; the actual comparison
* is below.
*/
tmptup = brin_form_placeholder_tuple(bdesc, heapBlk, &tmpsiz);
tmpdtup = brin_deform_tuple(bdesc, tmptup);
for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
{
BrinValues *bval;
FmgrInfo *addValue;
bval = &tmpdtup->bt_columns[keyno];
addValue = index_getprocinfo(idxRel, keyno + 1,
BRIN_PROCNUM_ADDVALUE);
FunctionCall4Coll(addValue,
idxRel->rd_indcollation[keyno],
PointerGetDatum(bdesc),
PointerGetDatum(bval),
values[keyno],
nulls[keyno]);
}
union_tuples(bdesc, tmpdtup, brtup);
tmpdtup->bt_placeholder = dtup->bt_placeholder;
tmptup = brin_form_tuple(bdesc, heapBlk, tmpdtup, &tmpsiz);
}
#endif
/*
* Compare the key values of the new tuple to the stored index values;
* our deformed tuple will get updated if the new tuple doesn't fit
* the original range (note this means we can't break out of the loop
* early). Make a note of whether this happens, so that we know to
* insert the modified tuple later.
*/
for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
{
Datum result;
BrinValues *bval;
FmgrInfo *addValue;
bval = &dtup->bt_columns[keyno];
addValue = index_getprocinfo(idxRel, keyno + 1,
BRIN_PROCNUM_ADDVALUE);
result = FunctionCall4Coll(addValue,
idxRel->rd_indcollation[keyno],
PointerGetDatum(bdesc),
PointerGetDatum(bval),
values[keyno],
nulls[keyno]);
/* if that returned true, we need to insert the updated tuple */
need_insert |= DatumGetBool(result);
}
#ifdef USE_ASSERT_CHECKING
{
/*
* Now we can compare the tuple produced by the union function
* with the one from plain addValue.
*/
BrinTuple *cmptup;
Size cmpsz;
cmptup = brin_form_tuple(bdesc, heapBlk, dtup, &cmpsz);
Assert(brin_tuples_equal(tmptup, tmpsiz, cmptup, cmpsz));
}
#endif
if (!need_insert)
{
/*
* The tuple is consistent with the new values, so there's nothing
* to do.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
else
{
Page page = BufferGetPage(buf);
ItemId lp = PageGetItemId(page, off);
Size origsz;
BrinTuple *origtup;
Size newsz;
BrinTuple *newtup;
bool samepage;
/*
* Make a copy of the old tuple, so that we can compare it after
* re-acquiring the lock.
*/
origsz = ItemIdGetLength(lp);
origtup = brin_copy_tuple(brtup, origsz);
/*
* Before releasing the lock, check if we can attempt a same-page
* update. Another process could insert a tuple concurrently in
* the same page though, so downstream we must be prepared to cope
* if this turns out to not be possible after all.
*/
newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
samepage = brin_can_do_samepage_update(buf, origsz, newsz);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/*
* Try to update the tuple. If this doesn't work for whatever
* reason, we need to restart from the top; the revmap might be
* pointing at a different tuple for this block now, so we need to
* recompute to ensure both our new heap tuple and the other
* inserter's are covered by the combined tuple. It might be that
* we don't need to update at all.
*/
if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
buf, off, origtup, origsz, newtup, newsz,
samepage))
{
/* no luck; start over */
MemoryContextResetAndDeleteChildren(tupcxt);
continue;
}
}
/* success! */
break;
}
brinRevmapTerminate(revmap);
if (BufferIsValid(buf))
ReleaseBuffer(buf);
if (bdesc != NULL)
{
brin_free_desc(bdesc);
MemoryContextSwitchTo(oldcxt);
MemoryContextDelete(tupcxt);
}
return BoolGetDatum(false);
}
/*
* Scan a complete BRIN index, and summarize each page range that's not already
* summarized. The index and heap must have been locked by caller in at
* least ShareUpdateExclusiveLock mode.
*
* For each new index tuple inserted, *numSummarized (if not NULL) is
* incremented; for each existing tuple, numExisting (if not NULL) is
* incremented.
*/
static void
brinsummarize(Relation index, Relation heapRel, double *numSummarized,
double *numExisting)
{
BrinRevmap *revmap;
BrinBuildState *state = NULL;
IndexInfo *indexInfo = NULL;
BlockNumber heapNumBlocks;
BlockNumber heapBlk;
BlockNumber pagesPerRange;
Buffer buf;
revmap = brinRevmapInitialize(index, &pagesPerRange);
/*
* Scan the revmap to find unsummarized items.
*/
buf = InvalidBuffer;
heapNumBlocks = RelationGetNumberOfBlocks(heapRel);
for (heapBlk = 0; heapBlk < heapNumBlocks; heapBlk += pagesPerRange)
{
BrinTuple *tup;
OffsetNumber off;
CHECK_FOR_INTERRUPTS();
tup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off, NULL,
BUFFER_LOCK_SHARE);
if (tup == NULL)
{
/* no revmap entry for this heap range. Summarize it. */
if (state == NULL)
{
/* first time through */
Assert(!indexInfo);
state = initialize_brin_buildstate(index, revmap,
pagesPerRange);
indexInfo = BuildIndexInfo(index);
/*
* We only have ShareUpdateExclusiveLock on the table, and
* therefore other sessions may insert tuples into the range
* we're going to scan. This is okay, because we take
* additional precautions to avoid losing the additional
* tuples; see comments in summarize_range. Set the
* concurrent flag, which causes IndexBuildHeapRangeScan to
* use a snapshot other than SnapshotAny, and silences
* warnings emitted there.
*/
indexInfo->ii_Concurrent = true;
/*
* If using transaction-snapshot mode, it would be possible
* for another transaction to insert a tuple that's not
* visible to our snapshot if we have already acquired one,
* when in snapshot-isolation mode; therefore, disallow this
* from running in such a transaction unless a snapshot hasn't
* been acquired yet.
*
* This code is called by VACUUM and
* brin_summarize_new_values. Have the error message mention
* the latter because VACUUM cannot run in a transaction and
* thus cannot cause this issue.
*/
if (IsolationUsesXactSnapshot() && FirstSnapshotSet)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("brin_summarize_new_values() cannot run in a transaction that has already obtained a snapshot")));
}
summarize_range(indexInfo, state, heapRel, heapBlk);
/* and re-initialize state for the next range */
brin_memtuple_initialize(state->bs_dtuple, state->bs_bdesc);
if (numSummarized)
*numSummarized += 1.0;
}
else
{
if (numExisting)
*numExisting += 1.0;
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
}
if (BufferIsValid(buf))
ReleaseBuffer(buf);
/* free resources */
brinRevmapTerminate(revmap);
if (state)
terminate_brin_buildstate(state);
}
/*
* A tuple in the heap is being inserted. To keep a brin index up to date,
* we need to obtain the relevant index tuple and compare its stored values
* with those of the new tuple. If the tuple values are not consistent with
* the summary tuple, we need to update the index tuple.
*
* If autosummarization is enabled, check if we need to summarize the previous
* page range.
*
* If the range is not currently summarized (i.e. the revmap returns NULL for
* it), there's nothing to do for this tuple.
*/
bool
brininsert(Relation idxRel, Datum *values, bool *nulls,
ItemPointer heaptid, Relation heapRel,
IndexUniqueCheck checkUnique,
IndexInfo *indexInfo)
{
BlockNumber pagesPerRange;
BlockNumber origHeapBlk;
BlockNumber heapBlk;
BrinDesc *bdesc = (BrinDesc *) indexInfo->ii_AmCache;
BrinRevmap *revmap;
Buffer buf = InvalidBuffer;
MemoryContext tupcxt = NULL;
MemoryContext oldcxt = CurrentMemoryContext;
bool autosummarize = BrinGetAutoSummarize(idxRel);
revmap = brinRevmapInitialize(idxRel, &pagesPerRange, NULL);
/*
* origHeapBlk is the block number where the insertion occurred. heapBlk
* is the first block in the corresponding page range.
*/
origHeapBlk = ItemPointerGetBlockNumber(heaptid);
heapBlk = (origHeapBlk / pagesPerRange) * pagesPerRange;
for (;;)
{
bool need_insert = false;
OffsetNumber off;
BrinTuple *brtup;
BrinMemTuple *dtup;
int keyno;
CHECK_FOR_INTERRUPTS();
/*
* If auto-summarization is enabled and we just inserted the first
* tuple into the first block of a new non-first page range, request a
* summarization run of the previous range.
*/
if (autosummarize &&
heapBlk > 0 &&
heapBlk == origHeapBlk &&
ItemPointerGetOffsetNumber(heaptid) == FirstOffsetNumber)
{
BlockNumber lastPageRange = heapBlk - 1;
BrinTuple *lastPageTuple;
lastPageTuple =
brinGetTupleForHeapBlock(revmap, lastPageRange, &buf, &off,
NULL, BUFFER_LOCK_SHARE, NULL);
if (!lastPageTuple)
{
bool recorded;
recorded = AutoVacuumRequestWork(AVW_BRINSummarizeRange,
RelationGetRelid(idxRel),
lastPageRange);
if (!recorded)
ereport(LOG,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("request for BRIN range summarization for index \"%s\" page %u was not recorded",
RelationGetRelationName(idxRel),
lastPageRange)));
}
else
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off,
NULL, BUFFER_LOCK_SHARE, NULL);
/* if range is unsummarized, there's nothing to do */
if (!brtup)
break;
/* First time through in this statement? */
if (bdesc == NULL)
{
MemoryContextSwitchTo(indexInfo->ii_Context);
bdesc = brin_build_desc(idxRel);
indexInfo->ii_AmCache = (void *) bdesc;
MemoryContextSwitchTo(oldcxt);
}
/* First time through in this brininsert call? */
if (tupcxt == NULL)
{
tupcxt = AllocSetContextCreate(CurrentMemoryContext,
"brininsert cxt",
ALLOCSET_DEFAULT_SIZES);
MemoryContextSwitchTo(tupcxt);
}
dtup = brin_deform_tuple(bdesc, brtup, NULL);
/*
* Compare the key values of the new tuple to the stored index values;
* our deformed tuple will get updated if the new tuple doesn't fit
* the original range (note this means we can't break out of the loop
* early). Make a note of whether this happens, so that we know to
* insert the modified tuple later.
*/
for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
{
Datum result;
BrinValues *bval;
FmgrInfo *addValue;
bval = &dtup->bt_columns[keyno];
addValue = index_getprocinfo(idxRel, keyno + 1,
BRIN_PROCNUM_ADDVALUE);
result = FunctionCall4Coll(addValue,
idxRel->rd_indcollation[keyno],
PointerGetDatum(bdesc),
PointerGetDatum(bval),
values[keyno],
nulls[keyno]);
/* if that returned true, we need to insert the updated tuple */
need_insert |= DatumGetBool(result);
}
if (!need_insert)
{
/*
* The tuple is consistent with the new values, so there's nothing
* to do.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
else
{
Page page = BufferGetPage(buf);
ItemId lp = PageGetItemId(page, off);
Size origsz;
BrinTuple *origtup;
Size newsz;
BrinTuple *newtup;
bool samepage;
/*
* Make a copy of the old tuple, so that we can compare it after
* re-acquiring the lock.
*/
origsz = ItemIdGetLength(lp);
origtup = brin_copy_tuple(brtup, origsz, NULL, NULL);
/*
* Before releasing the lock, check if we can attempt a same-page
* update. Another process could insert a tuple concurrently in
* the same page though, so downstream we must be prepared to cope
* if this turns out to not be possible after all.
*/
newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
samepage = brin_can_do_samepage_update(buf, origsz, newsz);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/*
* Try to update the tuple. If this doesn't work for whatever
* reason, we need to restart from the top; the revmap might be
* pointing at a different tuple for this block now, so we need to
* recompute to ensure both our new heap tuple and the other
* inserter's are covered by the combined tuple. It might be that
* we don't need to update at all.
*/
if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
buf, off, origtup, origsz, newtup, newsz,
samepage))
{
/* no luck; start over */
MemoryContextResetAndDeleteChildren(tupcxt);
continue;
}
}
/* success! */
break;
}
brinRevmapTerminate(revmap);
if (BufferIsValid(buf))
ReleaseBuffer(buf);
MemoryContextSwitchTo(oldcxt);
if (tupcxt != NULL)
MemoryContextDelete(tupcxt);
return false;
}
/*
* Summarize page ranges that are not already summarized. If pageRange is
* BRIN_ALL_BLOCKRANGES then the whole table is scanned; otherwise, only the
* page range containing the given heap page number is scanned.
* If include_partial is true, then the partial range at the end of the table
* is summarized, otherwise not.
*
* For each new index tuple inserted, *numSummarized (if not NULL) is
* incremented; for each existing tuple, *numExisting (if not NULL) is
* incremented.
*/
static void
brinsummarize(Relation index, Relation heapRel, BlockNumber pageRange,
bool include_partial, double *numSummarized, double *numExisting)
{
BrinRevmap *revmap;
BrinBuildState *state = NULL;
IndexInfo *indexInfo = NULL;
BlockNumber heapNumBlocks;
BlockNumber pagesPerRange;
Buffer buf;
BlockNumber startBlk;
revmap = brinRevmapInitialize(index, &pagesPerRange, NULL);
/* determine range of pages to process */
heapNumBlocks = RelationGetNumberOfBlocks(heapRel);
if (pageRange == BRIN_ALL_BLOCKRANGES)
startBlk = 0;
else
{
startBlk = (pageRange / pagesPerRange) * pagesPerRange;
heapNumBlocks = Min(heapNumBlocks, startBlk + pagesPerRange);
}
if (startBlk > heapNumBlocks)
{
/* Nothing to do if start point is beyond end of table */
brinRevmapTerminate(revmap);
return;
}
/*
* Scan the revmap to find unsummarized items.
*/
buf = InvalidBuffer;
for (; startBlk < heapNumBlocks; startBlk += pagesPerRange)
{
BrinTuple *tup;
OffsetNumber off;
/*
* Unless requested to summarize even a partial range, go away now if
* we think the next range is partial. Caller would pass true when it
* is typically run once bulk data loading is done
* (brin_summarize_new_values), and false when it is typically the
* result of arbitrarily-scheduled maintenance command (vacuuming).
*/
if (!include_partial &&
(startBlk + pagesPerRange > heapNumBlocks))
break;
CHECK_FOR_INTERRUPTS();
tup = brinGetTupleForHeapBlock(revmap, startBlk, &buf, &off, NULL,
BUFFER_LOCK_SHARE, NULL);
if (tup == NULL)
{
/* no revmap entry for this heap range. Summarize it. */
if (state == NULL)
{
/* first time through */
Assert(!indexInfo);
state = initialize_brin_buildstate(index, revmap,
pagesPerRange);
indexInfo = BuildIndexInfo(index);
}
summarize_range(indexInfo, state, heapRel, startBlk, heapNumBlocks);
/* and re-initialize state for the next range */
brin_memtuple_initialize(state->bs_dtuple, state->bs_bdesc);
if (numSummarized)
*numSummarized += 1.0;
}
else
{
if (numExisting)
*numExisting += 1.0;
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
}
if (BufferIsValid(buf))
ReleaseBuffer(buf);
/* free resources */
brinRevmapTerminate(revmap);
if (state)
{
terminate_brin_buildstate(state);
pfree(indexInfo);
}
}
