Datum
readindex(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
readindexinfo *info;
Relation irel = NULL;
Relation hrel = NULL;
MIRROREDLOCK_BUFMGR_DECLARE;
if (SRF_IS_FIRSTCALL())
{
Oid irelid = PG_GETARG_OID(0);
TupleDesc tupdesc;
MemoryContext oldcontext;
AttrNumber outattnum;
TupleDesc itupdesc;
int i;
AttrNumber attno;
irel = index_open(irelid, AccessShareLock);
itupdesc = RelationGetDescr(irel);
outattnum = FIXED_COLUMN + itupdesc->natts;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
tupdesc = CreateTemplateTupleDesc(outattnum, false);
attno = 1;
TupleDescInitEntry(tupdesc, attno++, "ictid", TIDOID, -1, 0);
TupleDescInitEntry(tupdesc, attno++, "hctid", TIDOID, -1, 0);
TupleDescInitEntry(tupdesc, attno++, "aotid", TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, attno++, "istatus", TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, attno++, "hstatus", TEXTOID, -1, 0);
for (i = 0; i < itupdesc->natts; i++)
{
Form_pg_attribute attr = itupdesc->attrs[i];
TupleDescInitEntry(tupdesc, attno++, NameStr(attr->attname), attr->atttypid, attr->atttypmod, 0);
}
funcctx->tuple_desc = BlessTupleDesc(tupdesc);
info = (readindexinfo *) palloc(sizeof(readindexinfo));
funcctx->user_fctx = (void *) info;
info->outattnum = outattnum;
info->ireloid = irelid;
hrel = relation_open(irel->rd_index->indrelid, AccessShareLock);
if (hrel->rd_rel != NULL &&
(hrel->rd_rel->relstorage == 'a' ||
hrel->rd_rel->relstorage == 'c'))
{
relation_close(hrel, AccessShareLock);
hrel = NULL;
info->hreloid = InvalidOid;
}
else
info->hreloid = irel->rd_index->indrelid;
info->num_pages = RelationGetNumberOfBlocks(irel);
info->blkno = BTREE_METAPAGE + 1;
info->page = NULL;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
info = (readindexinfo *) funcctx->user_fctx;
/*
* Open the relations (on first call, we did that above already).
* We unfortunately have to look up the relcache entry on every call,
* because if we store it in the cross-call context, we won't get a
* chance to release it if the function isn't run to completion,
* e.g. because of a LIMIT clause. We only lock the relation on the
* first call, and keep the lock until completion, however.
*/
if (!irel)
irel = index_open(info->ireloid, NoLock);
if (!hrel && info->hreloid != InvalidOid)
hrel = heap_open(info->hreloid, NoLock);
while (info->blkno < info->num_pages)
{
Datum values[255];
bool nulls[255];
ItemPointerData itid;
HeapTuple tuple;
Datum result;
if (info->page == NULL)
{
Buffer buf;
/*
* Make copy of the page, because we cannot hold a buffer pin
* across calls (we wouldn't have a chance to release it, if the
* function isn't run to completion.)
*/
info->page = palloc(BLCKSZ);
MIRROREDLOCK_BUFMGR_LOCK;
buf = ReadBuffer(irel, info->blkno);
memcpy(info->page, BufferGetPage(buf), BLCKSZ);
ReleaseBuffer(buf);
MIRROREDLOCK_BUFMGR_UNLOCK;
info->opaque = (BTPageOpaque) PageGetSpecialPointer(info->page);
info->minoff = P_FIRSTDATAKEY(info->opaque);
info->maxoff = PageGetMaxOffsetNumber(info->page);
info->offnum = info->minoff;
}
if (!P_ISLEAF(info->opaque) || info->offnum > info->maxoff)
{
pfree(info->page);
info->page = NULL;
info->blkno++;
continue;
}
MemSet(nulls, false, info->outattnum * sizeof(bool));
ItemPointerSet(&itid, info->blkno, info->offnum);
values[0] = ItemPointerGetDatum(&itid);
readindextuple(info, irel, hrel, values, nulls);
info->offnum = OffsetNumberNext(info->offnum);
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
if (hrel != NULL)
heap_close(hrel, NoLock);
index_close(irel, NoLock);
SRF_RETURN_NEXT(funcctx, result);
}
if (hrel != NULL)
heap_close(hrel, AccessShareLock);
index_close(irel, AccessShareLock);
SRF_RETURN_DONE(funcctx);
}
Datum
readindex(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
readindexinfo *info;
MIRROREDLOCK_BUFMGR_DECLARE;
if (SRF_IS_FIRSTCALL())
{
Oid irelid = PG_GETARG_OID(0);
TupleDesc tupdesc;
MemoryContext oldcontext;
AttrNumber outattnum;
Relation irel;
TupleDesc itupdesc;
int i;
AttrNumber attno;
irel = index_open(irelid, AccessShareLock);
itupdesc = RelationGetDescr(irel);
outattnum = FIXED_COLUMN + itupdesc->natts;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
tupdesc = CreateTemplateTupleDesc(outattnum, false);
attno = 1;
TupleDescInitEntry(tupdesc, attno++, "ictid", TIDOID, -1, 0);
TupleDescInitEntry(tupdesc, attno++, "hctid", TIDOID, -1, 0);
TupleDescInitEntry(tupdesc, attno++, "aotid", TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, attno++, "istatus", TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, attno++, "hstatus", TEXTOID, -1, 0);
for (i = 0; i < itupdesc->natts; i++)
{
Form_pg_attribute attr = itupdesc->attrs[i];
TupleDescInitEntry(tupdesc, attno++, NameStr(attr->attname), attr->atttypid, attr->atttypmod, 0);
}
funcctx->tuple_desc = BlessTupleDesc(tupdesc);
info = (readindexinfo *) palloc(sizeof(readindexinfo));
funcctx->user_fctx = (void *) info;
info->outattnum = outattnum;
info->irel = irel;
info->hrel = relation_open(irel->rd_index->indrelid, AccessShareLock);
if (info->hrel->rd_rel != NULL &&
(info->hrel->rd_rel->relstorage == 'a' ||
info->hrel->rd_rel->relstorage == 'c'))
{
relation_close(info->hrel, AccessShareLock);
info->hrel = NULL;
}
info->num_pages = RelationGetNumberOfBlocks(irel);
info->blkno = BTREE_METAPAGE + 1;
info->page = NULL;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
info = (readindexinfo *) funcctx->user_fctx;
while (info->blkno < info->num_pages)
{
Datum values[255];
bool nulls[255];
ItemPointerData itid;
HeapTuple tuple;
Datum result;
if (info->page == NULL)
{
MIRROREDLOCK_BUFMGR_LOCK;
info->buf = ReadBuffer(info->irel, info->blkno);
info->page = BufferGetPage(info->buf);
info->opaque = (BTPageOpaque) PageGetSpecialPointer(info->page);
info->minoff = P_FIRSTDATAKEY(info->opaque);
info->maxoff = PageGetMaxOffsetNumber(info->page);
info->offnum = info->minoff;
MIRROREDLOCK_BUFMGR_UNLOCK;
}
if (!P_ISLEAF(info->opaque) || info->offnum > info->maxoff)
{
ReleaseBuffer(info->buf);
info->page = NULL;
info->blkno++;
continue;
}
MemSet(nulls, false, info->outattnum * sizeof(bool));
ItemPointerSet(&itid, info->blkno, info->offnum);
values[0] = ItemPointerGetDatum(&itid);
readindextuple(info, values, nulls);
info->offnum = OffsetNumberNext(info->offnum);
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
if (info->hrel != NULL)
relation_close(info->hrel, AccessShareLock);
index_close(info->irel, AccessShareLock);
SRF_RETURN_DONE(funcctx);
}
