/*
* Visibility map information for a single block of a relation.
*/
Datum
pg_visibility_map(PG_FUNCTION_ARGS)
{
Oid relid = PG_GETARG_OID(0);
int64 blkno = PG_GETARG_INT64(1);
int32 mapbits;
Relation rel;
Buffer vmbuffer = InvalidBuffer;
TupleDesc tupdesc;
Datum values[2];
bool nulls[2];
rel = relation_open(relid, AccessShareLock);
if (blkno < 0 || blkno > MaxBlockNumber)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid block number")));
tupdesc = pg_visibility_tupdesc(false, false);
MemSet(nulls, 0, sizeof(nulls));
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
if (vmbuffer != InvalidBuffer)
ReleaseBuffer(vmbuffer);
values[0] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0);
values[1] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0);
relation_close(rel, AccessShareLock);
PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
/*
* Collect visibility data about a relation.
*/
static vbits *
collect_visibility_data(Oid relid, bool include_pd)
{
Relation rel;
BlockNumber nblocks;
vbits *info;
BlockNumber blkno;
Buffer vmbuffer = InvalidBuffer;
BufferAccessStrategy bstrategy = GetAccessStrategy(BAS_BULKREAD);
rel = relation_open(relid, AccessShareLock);
nblocks = RelationGetNumberOfBlocks(rel);
info = palloc0(offsetof(vbits, bits) + nblocks);
info->next = 0;
info->count = nblocks;
for (blkno = 0; blkno < nblocks; ++blkno)
{
int32 mapbits;
/* Make sure we are interruptible. */
CHECK_FOR_INTERRUPTS();
/* Get map info. */
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
if ((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0)
info->bits[blkno] |= (1 << 0);
if ((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0)
info->bits[blkno] |= (1 << 1);
/*
* Page-level data requires reading every block, so only get it if
* the caller needs it. Use a buffer access strategy, too, to prevent
* cache-trashing.
*/
if (include_pd)
{
Buffer buffer;
Page page;
buffer = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL,
bstrategy);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
if (PageIsAllVisible(page))
info->bits[blkno] |= (1 << 2);
UnlockReleaseBuffer(buffer);
}
}
/* Clean up. */
if (vmbuffer != InvalidBuffer)
ReleaseBuffer(vmbuffer);
relation_close(rel, AccessShareLock);
return info;
}
/*
* Visibility map information for a single block of a relation, plus the
* page-level information for the same block.
*/
Datum
pg_visibility(PG_FUNCTION_ARGS)
{
Oid relid = PG_GETARG_OID(0);
int64 blkno = PG_GETARG_INT64(1);
int32 mapbits;
Relation rel;
Buffer vmbuffer = InvalidBuffer;
Buffer buffer;
Page page;
TupleDesc tupdesc;
Datum values[3];
bool nulls[3];
rel = relation_open(relid, AccessShareLock);
/* Only some relkinds have a visibility map */
check_relation_relkind(rel);
if (blkno < 0 || blkno > MaxBlockNumber)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid block number")));
tupdesc = pg_visibility_tupdesc(false, true);
MemSet(nulls, 0, sizeof(nulls));
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
if (vmbuffer != InvalidBuffer)
ReleaseBuffer(vmbuffer);
values[0] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0);
values[1] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0);
/* Here we have to explicitly check rel size ... */
if (blkno < RelationGetNumberOfBlocks(rel))
{
buffer = ReadBuffer(rel, blkno);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = BufferGetPage(buffer);
values[2] = BoolGetDatum(PageIsAllVisible(page));
UnlockReleaseBuffer(buffer);
}
else
{
/* As with the vismap, silently return 0 for pages past EOF */
values[2] = BoolGetDatum(false);
}
relation_close(rel, AccessShareLock);
PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
/*
* Count the number of all-visible and all-frozen pages in the visibility
* map for a particular relation.
*/
Datum
pg_visibility_map_summary(PG_FUNCTION_ARGS)
{
Oid relid = PG_GETARG_OID(0);
Relation rel;
BlockNumber nblocks;
BlockNumber blkno;
Buffer vmbuffer = InvalidBuffer;
int64 all_visible = 0;
int64 all_frozen = 0;
TupleDesc tupdesc;
Datum values[2];
bool nulls[2];
rel = relation_open(relid, AccessShareLock);
/* Only some relkinds have a visibility map */
check_relation_relkind(rel);
nblocks = RelationGetNumberOfBlocks(rel);
for (blkno = 0; blkno < nblocks; ++blkno)
{
int32 mapbits;
/* Make sure we are interruptible. */
CHECK_FOR_INTERRUPTS();
/* Get map info. */
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
if ((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0)
++all_visible;
if ((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0)
++all_frozen;
}
/* Clean up. */
if (vmbuffer != InvalidBuffer)
ReleaseBuffer(vmbuffer);
relation_close(rel, AccessShareLock);
tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "all_visible", INT8OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "all_frozen", INT8OID, -1, 0);
tupdesc = BlessTupleDesc(tupdesc);
MemSet(nulls, 0, sizeof(nulls));
values[0] = Int64GetDatum(all_visible);
values[1] = Int64GetDatum(all_frozen);
PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
/*
* Visibility map information for a single block of a relation, plus the
* page-level information for the same block.
*/
Datum
pg_visibility(PG_FUNCTION_ARGS)
{
Oid relid = PG_GETARG_OID(0);
int64 blkno = PG_GETARG_INT64(1);
int32 mapbits;
Relation rel;
Buffer vmbuffer = InvalidBuffer;
Buffer buffer;
Page page;
TupleDesc tupdesc;
Datum values[3];
bool nulls[3];
rel = relation_open(relid, AccessShareLock);
if (blkno < 0 || blkno > MaxBlockNumber)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid block number")));
tupdesc = pg_visibility_tupdesc(false, true);
MemSet(nulls, 0, sizeof(nulls));
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
if (vmbuffer != InvalidBuffer)
ReleaseBuffer(vmbuffer);
values[0] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0);
values[1] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0);
buffer = ReadBuffer(rel, blkno);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
values[2] = BoolGetDatum(PageIsAllVisible(page));
UnlockReleaseBuffer(buffer);
relation_close(rel, AccessShareLock);
PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
