/*
* OperatorGet
*
* finds an operator given an exact specification (name, namespace,
* left and right type IDs).
*
* *defined is set TRUE if defined (not a shell)
*/
static Oid
OperatorGet(const char *operatorName,
Oid operatorNamespace,
Oid leftObjectId,
Oid rightObjectId,
bool *defined)
{
HeapTuple tup;
Oid operatorObjectId;
tup = SearchSysCache4(OPERNAMENSP,
PointerGetDatum(operatorName),
ObjectIdGetDatum(leftObjectId),
ObjectIdGetDatum(rightObjectId),
ObjectIdGetDatum(operatorNamespace));
if (HeapTupleIsValid(tup))
{
RegProcedure oprcode = ((Form_pg_operator) GETSTRUCT(tup))->oprcode;
operatorObjectId = HeapTupleGetOid(tup);
*defined = RegProcedureIsValid(oprcode);
ReleaseSysCache(tup);
}
else
{
operatorObjectId = InvalidOid;
*defined = false;
}
return operatorObjectId;
}
/*
* ScanKeyEntryInitialize
* Initializes a scan key entry given all the field values.
* The target procedure is specified by OID (but can be invalid
* if SK_SEARCHNULL or SK_SEARCHNOTNULL is set).
*
* Note: CurrentMemoryContext at call should be as long-lived as the ScanKey
* itself, because that's what will be used for any subsidiary info attached
* to the ScanKey's FmgrInfo record.
*/
void
ScanKeyEntryInitialize(ScanKey entry,
int flags,
AttrNumber attributeNumber,
StrategyNumber strategy,
Oid subtype,
Oid collation,
RegProcedure procedure,
Datum argument)
{
entry->sk_flags = flags;
entry->sk_attno = attributeNumber;
entry->sk_strategy = strategy;
entry->sk_subtype = subtype;
entry->sk_collation = collation;
entry->sk_argument = argument;
if (RegProcedureIsValid(procedure))
{
fmgr_info(procedure, &entry->sk_func);
}
else
{
Assert(flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
MemSet(&entry->sk_func, 0, sizeof(entry->sk_func));
}
}
/*
* Cache and return the procedure for the given strategy.
*/
FmgrInfo *
minmax_get_strategy_procinfo(BrinDesc *bdesc, uint16 attno, Oid subtype,
uint16 strategynum)
{
MinmaxOpaque *opaque;
Assert(strategynum >= 1 &&
strategynum <= BTMaxStrategyNumber);
opaque = (MinmaxOpaque *) bdesc->bd_info[attno - 1]->oi_opaque;
/*
* We cache the procedures for the previous subtype in the opaque struct,
* to avoid repetitive syscache lookups. If the subtype changed,
* invalidate all the cached entries.
*/
if (opaque->cached_subtype != subtype)
{
uint16 i;
for (i = 1; i <= BTMaxStrategyNumber; i++)
opaque->strategy_procinfos[i - 1].fn_oid = InvalidOid;
opaque->cached_subtype = subtype;
}
if (opaque->strategy_procinfos[strategynum - 1].fn_oid == InvalidOid)
{
Form_pg_attribute attr;
HeapTuple tuple;
Oid opfamily,
oprid;
bool isNull;
opfamily = bdesc->bd_index->rd_opfamily[attno - 1];
attr = bdesc->bd_tupdesc->attrs[attno - 1];
tuple = SearchSysCache4(AMOPSTRATEGY, ObjectIdGetDatum(opfamily),
ObjectIdGetDatum(attr->atttypid),
ObjectIdGetDatum(subtype),
Int16GetDatum(strategynum));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
strategynum, attr->atttypid, subtype, opfamily);
oprid = DatumGetObjectId(SysCacheGetAttr(AMOPSTRATEGY, tuple,
Anum_pg_amop_amopopr, &isNull));
ReleaseSysCache(tuple);
Assert(!isNull && RegProcedureIsValid(oprid));
fmgr_info_cxt(get_opcode(oprid),
&opaque->strategy_procinfos[strategynum - 1],
bdesc->bd_context);
}
return &opaque->strategy_procinfos[strategynum - 1];
}
/* ----------------
* index_getprocinfo
*
* This routine allows index AMs to keep fmgr lookup info for
* support procs in the relcache. As above, only the "default"
* functions for any particular indexed attribute are cached.
*
* Note: the return value points into cached data that will be lost during
* any relcache rebuild! Therefore, either use the callinfo right away,
* or save it only after having acquired some type of lock on the index rel.
* ----------------
*/
FmgrInfo *
index_getprocinfo(Relation irel,
AttrNumber attnum,
uint16 procnum)
{
FmgrInfo *locinfo;
int nproc;
int procindex;
nproc = irel->rd_am->amsupport;
Assert(procnum > 0 && procnum <= (uint16) nproc);
procindex = (nproc * (attnum - 1)) + (procnum - 1);
locinfo = irel->rd_supportinfo;
Assert(locinfo != NULL);
locinfo += procindex;
/* Initialize the lookup info if first time through */
if (locinfo->fn_oid == InvalidOid)
{
RegProcedure *loc = irel->rd_support;
RegProcedure procId;
Assert(loc != NULL);
procId = loc[procindex];
/*
* Complain if function was not found during IndexSupportInitialize.
* This should not happen unless the system tables contain bogus
* entries for the index opclass. (If an AM wants to allow a support
* function to be optional, it can use index_getprocid.)
*/
if (!RegProcedureIsValid(procId))
elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
procnum, attnum, RelationGetRelationName(irel));
fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
fmgr_info_collation(irel->rd_index->indcollation.values[attnum-1],
locinfo);
}
return locinfo;
}
/* ----------------
* index_can_return - does index support index-only scans?
* ----------------
*/
bool
index_can_return(Relation indexRelation)
{
FmgrInfo *procedure;
RELATION_CHECKS;
/* amcanreturn is optional; assume FALSE if not provided by AM */
if (!RegProcedureIsValid(indexRelation->rd_am->amcanreturn))
return false;
GET_REL_PROCEDURE(amcanreturn);
return DatumGetBool(FunctionCall1(procedure,
PointerGetDatum(indexRelation)));
}
/*
* _hash_datum2hashkey_type -- given a Datum of a specified type,
* hash it in a fashion compatible with this index
*
* This is much more expensive than _hash_datum2hashkey, so use it only in
* cross-type situations.
*/
uint32
_hash_datum2hashkey_type(Relation rel, Datum key, Oid keytype)
{
RegProcedure hash_proc;
/* XXX assumes index has only one attribute */
hash_proc = get_opfamily_proc(rel->rd_opfamily[0],
keytype,
keytype,
HASHPROC);
if (!RegProcedureIsValid(hash_proc))
elog(ERROR, "missing support function %d(%u,%u) for index \"%s\"",
HASHPROC, keytype, keytype,
RelationGetRelationName(rel));
return DatumGetUInt32(OidFunctionCall1(hash_proc, key));
}
/*
* OperatorGet
*
* finds an operator given an exact specification (name, namespace,
* left and right type IDs).
*
* *defined is set TRUE if defined (not a shell)
*/
static Oid
OperatorGet(const char *operatorName,
Oid operatorNamespace,
Oid leftObjectId,
Oid rightObjectId,
bool *defined)
{
HeapTuple tup;
Oid operatorObjectId;
cqContext *pcqCtx;
pcqCtx = caql_beginscan(
NULL,
cql("SELECT * FROM pg_operator "
" WHERE oprname = :1 "
" AND oprleft = :2 "
" AND oprright = :3 "
" AND oprnamespace = :4 ",
CStringGetDatum((char *) operatorName),
ObjectIdGetDatum(leftObjectId),
ObjectIdGetDatum(rightObjectId),
ObjectIdGetDatum(operatorNamespace)));
tup = caql_getnext(pcqCtx);
if (HeapTupleIsValid(tup))
{
RegProcedure oprcode = ((Form_pg_operator) GETSTRUCT(tup))->oprcode;
operatorObjectId = HeapTupleGetOid(tup);
*defined = RegProcedureIsValid(oprcode);
}
else
{
operatorObjectId = InvalidOid;
*defined = false;
}
caql_endscan(pcqCtx);
return operatorObjectId;
}
/*
* OperatorLookup
*
* looks up an operator given a possibly-qualified name and
* left and right type IDs.
*
* *defined is set TRUE if defined (not a shell)
*/
static Oid
OperatorLookup(List *operatorName,
Oid leftObjectId,
Oid rightObjectId,
bool *defined)
{
Oid operatorObjectId;
RegProcedure oprcode;
operatorObjectId = LookupOperName(operatorName, leftObjectId,
rightObjectId, true);
if (!OidIsValid(operatorObjectId))
{
*defined = false;
return InvalidOid;
}
oprcode = get_opcode(operatorObjectId);
*defined = RegProcedureIsValid(oprcode);
return operatorObjectId;
}
/* ----------------
* index_vacuum_cleanup - do post-deletion cleanup of an index
*
* return value is an optional palloc'd struct of statistics
* ----------------
*/
IndexBulkDeleteResult *
index_vacuum_cleanup(Relation indexRelation,
IndexVacuumCleanupInfo *info,
IndexBulkDeleteResult *stats)
{
RegProcedure procedure;
IndexBulkDeleteResult *result;
RELATION_CHECKS;
/* It's okay for an index AM not to have a vacuumcleanup procedure */
if (!RegProcedureIsValid(indexRelation->rd_am->amvacuumcleanup))
return stats;
GET_REL_PROCEDURE(vacuum_cleanup, amvacuumcleanup);
result = (IndexBulkDeleteResult *)
DatumGetPointer(OidFunctionCall3(procedure,
PointerGetDatum(indexRelation),
PointerGetDatum((Pointer) info),
PointerGetDatum((Pointer) stats)));
return result;
}
/*
* index_build - invoke access-method-specific index build procedure
*/
void
index_build(Relation heapRelation,
Relation indexRelation,
IndexInfo *indexInfo)
{
RegProcedure procedure;
/*
* sanity checks
*/
Assert(RelationIsValid(indexRelation));
Assert(PointerIsValid(indexRelation->rd_am));
procedure = indexRelation->rd_am->ambuild;
Assert(RegProcedureIsValid(procedure));
/*
* Call the access method's build procedure
*/
OidFunctionCall3(procedure,
PointerGetDatum(heapRelation),
PointerGetDatum(indexRelation),
PointerGetDatum(indexInfo));
}
/*
* _bt_first() -- Find the first item in a scan.
*
* We need to be clever about the direction of scan, the search
* conditions, and the tree ordering. We find the first item (or,
* if backwards scan, the last item) in the tree that satisfies the
* qualifications in the scan key. On success exit, the page containing
* the current index tuple is pinned but not locked, and data about
* the matching tuple(s) on the page has been loaded into so->currPos.
* scan->xs_ctup.t_self is set to the heap TID of the current tuple,
* and if requested, scan->xs_itup points to a copy of the index tuple.
*
* If there are no matching items in the index, we return FALSE, with no
* pins or locks held.
*
* Note that scan->keyData[], and the so->keyData[] scankey built from it,
* are both search-type scankeys (see nbtree/README for more about this).
* Within this routine, we build a temporary insertion-type scankey to use
* in locating the scan start position.
*/
bool
_bt_first(IndexScanDesc scan, ScanDirection dir)
{
Relation rel = scan->indexRelation;
BTScanOpaque so = (BTScanOpaque) scan->opaque;
Buffer buf;
BTStack stack;
OffsetNumber offnum;
StrategyNumber strat;
bool nextkey;
bool goback;
ScanKey startKeys[INDEX_MAX_KEYS];
ScanKeyData scankeys[INDEX_MAX_KEYS];
ScanKeyData notnullkeys[INDEX_MAX_KEYS];
int keysCount = 0;
int i;
StrategyNumber strat_total;
BTScanPosItem *currItem;
pgstat_count_index_scan(rel);
/*
* Examine the scan keys and eliminate any redundant keys; also mark the
* keys that must be matched to continue the scan.
*/
_bt_preprocess_keys(scan);
/*
* Quit now if _bt_preprocess_keys() discovered that the scan keys can
* never be satisfied (eg, x == 1 AND x > 2).
*/
if (!so->qual_ok)
return false;
/*----------
* Examine the scan keys to discover where we need to start the scan.
*
* We want to identify the keys that can be used as starting boundaries;
* these are =, >, or >= keys for a forward scan or =, <, <= keys for
* a backwards scan. We can use keys for multiple attributes so long as
* the prior attributes had only =, >= (resp. =, <=) keys. Once we accept
* a > or < boundary or find an attribute with no boundary (which can be
* thought of as the same as "> -infinity"), we can't use keys for any
* attributes to its right, because it would break our simplistic notion
* of what initial positioning strategy to use.
*
* When the scan keys include cross-type operators, _bt_preprocess_keys
* may not be able to eliminate redundant keys; in such cases we will
* arbitrarily pick a usable one for each attribute. This is correct
* but possibly not optimal behavior. (For example, with keys like
* "x >= 4 AND x >= 5" we would elect to scan starting at x=4 when
* x=5 would be more efficient.) Since the situation only arises given
* a poorly-worded query plus an incomplete opfamily, live with it.
*
* When both equality and inequality keys appear for a single attribute
* (again, only possible when cross-type operators appear), we *must*
* select one of the equality keys for the starting point, because
* _bt_checkkeys() will stop the scan as soon as an equality qual fails.
* For example, if we have keys like "x >= 4 AND x = 10" and we elect to
* start at x=4, we will fail and stop before reaching x=10. If multiple
* equality quals survive preprocessing, however, it doesn't matter which
* one we use --- by definition, they are either redundant or
* contradictory.
*
* Any regular (not SK_SEARCHNULL) key implies a NOT NULL qualifier.
* If the index stores nulls at the end of the index we'll be starting
* from, and we have no boundary key for the column (which means the key
* we deduced NOT NULL from is an inequality key that constrains the other
* end of the index), then we cons up an explicit SK_SEARCHNOTNULL key to
* use as a boundary key. If we didn't do this, we might find ourselves
* traversing a lot of null entries at the start of the scan.
*
* In this loop, row-comparison keys are treated the same as keys on their
* first (leftmost) columns. We'll add on lower-order columns of the row
* comparison below, if possible.
*
* The selected scan keys (at most one per index column) are remembered by
* storing their addresses into the local startKeys[] array.
*----------
*/
strat_total = BTEqualStrategyNumber;
if (so->numberOfKeys > 0)
{
AttrNumber curattr;
ScanKey chosen;
ScanKey impliesNN;
ScanKey cur;
/*
* chosen is the so-far-chosen key for the current attribute, if any.
* We don't cast the decision in stone until we reach keys for the
* next attribute.
*/
curattr = 1;
chosen = NULL;
/* Also remember any scankey that implies a NOT NULL constraint */
impliesNN = NULL;
/*
* Loop iterates from 0 to numberOfKeys inclusive; we use the last
* pass to handle after-last-key processing. Actual exit from the
* loop is at one of the "break" statements below.
*/
for (cur = so->keyData, i = 0;; cur++, i++)
{
if (i >= so->numberOfKeys || cur->sk_attno != curattr)
{
/*
* Done looking at keys for curattr. If we didn't find a
* usable boundary key, see if we can deduce a NOT NULL key.
*/
if (chosen == NULL && impliesNN != NULL &&
((impliesNN->sk_flags & SK_BT_NULLS_FIRST) ?
ScanDirectionIsForward(dir) :
ScanDirectionIsBackward(dir)))
{
/* Yes, so build the key in notnullkeys[keysCount] */
chosen = ¬nullkeys[keysCount];
ScanKeyEntryInitialize(chosen,
(SK_SEARCHNOTNULL | SK_ISNULL |
(impliesNN->sk_flags &
(SK_BT_DESC | SK_BT_NULLS_FIRST))),
curattr,
((impliesNN->sk_flags & SK_BT_NULLS_FIRST) ?
BTGreaterStrategyNumber :
BTLessStrategyNumber),
InvalidOid,
InvalidOid,
InvalidOid,
(Datum) 0);
}
/*
* If we still didn't find a usable boundary key, quit; else
* save the boundary key pointer in startKeys.
*/
if (chosen == NULL)
break;
startKeys[keysCount++] = chosen;
/*
* Adjust strat_total, and quit if we have stored a > or <
* key.
*/
strat = chosen->sk_strategy;
if (strat != BTEqualStrategyNumber)
{
strat_total = strat;
if (strat == BTGreaterStrategyNumber ||
strat == BTLessStrategyNumber)
break;
}
/*
* Done if that was the last attribute, or if next key is not
* in sequence (implying no boundary key is available for the
* next attribute).
*/
if (i >= so->numberOfKeys ||
cur->sk_attno != curattr + 1)
break;
/*
* Reset for next attr.
*/
curattr = cur->sk_attno;
chosen = NULL;
impliesNN = NULL;
}
/*
* Can we use this key as a starting boundary for this attr?
*
* If not, does it imply a NOT NULL constraint? (Because
* SK_SEARCHNULL keys are always assigned BTEqualStrategyNumber,
* *any* inequality key works for that; we need not test.)
*/
switch (cur->sk_strategy)
{
case BTLessStrategyNumber:
case BTLessEqualStrategyNumber:
if (chosen == NULL)
{
if (ScanDirectionIsBackward(dir))
chosen = cur;
else
impliesNN = cur;
}
break;
case BTEqualStrategyNumber:
/* override any non-equality choice */
chosen = cur;
break;
case BTGreaterEqualStrategyNumber:
case BTGreaterStrategyNumber:
if (chosen == NULL)
{
if (ScanDirectionIsForward(dir))
chosen = cur;
else
impliesNN = cur;
}
break;
}
}
}
/*
* If we found no usable boundary keys, we have to start from one end of
* the tree. Walk down that edge to the first or last key, and scan from
* there.
*/
if (keysCount == 0)
return _bt_endpoint(scan, dir);
/*
* We want to start the scan somewhere within the index. Set up an
* insertion scankey we can use to search for the boundary point we
* identified above. The insertion scankey is built in the local
* scankeys[] array, using the keys identified by startKeys[].
*/
Assert(keysCount <= INDEX_MAX_KEYS);
for (i = 0; i < keysCount; i++)
{
ScanKey cur = startKeys[i];
Assert(cur->sk_attno == i + 1);
if (cur->sk_flags & SK_ROW_HEADER)
{
/*
* Row comparison header: look to the first row member instead.
*
* The member scankeys are already in insertion format (ie, they
* have sk_func = 3-way-comparison function), but we have to watch
* out for nulls, which _bt_preprocess_keys didn't check. A null
* in the first row member makes the condition unmatchable, just
* like qual_ok = false.
*/
ScanKey subkey = (ScanKey) DatumGetPointer(cur->sk_argument);
Assert(subkey->sk_flags & SK_ROW_MEMBER);
if (subkey->sk_flags & SK_ISNULL)
return false;
memcpy(scankeys + i, subkey, sizeof(ScanKeyData));
/*
* If the row comparison is the last positioning key we accepted,
* try to add additional keys from the lower-order row members.
* (If we accepted independent conditions on additional index
* columns, we use those instead --- doesn't seem worth trying to
* determine which is more restrictive.) Note that this is OK
* even if the row comparison is of ">" or "<" type, because the
* condition applied to all but the last row member is effectively
* ">=" or "<=", and so the extra keys don't break the positioning
* scheme. But, by the same token, if we aren't able to use all
* the row members, then the part of the row comparison that we
* did use has to be treated as just a ">=" or "<=" condition, and
* so we'd better adjust strat_total accordingly.
*/
if (i == keysCount - 1)
{
bool used_all_subkeys = false;
Assert(!(subkey->sk_flags & SK_ROW_END));
for (;;)
{
subkey++;
Assert(subkey->sk_flags & SK_ROW_MEMBER);
if (subkey->sk_attno != keysCount + 1)
break; /* out-of-sequence, can't use it */
if (subkey->sk_strategy != cur->sk_strategy)
break; /* wrong direction, can't use it */
if (subkey->sk_flags & SK_ISNULL)
break; /* can't use null keys */
Assert(keysCount < INDEX_MAX_KEYS);
memcpy(scankeys + keysCount, subkey, sizeof(ScanKeyData));
keysCount++;
if (subkey->sk_flags & SK_ROW_END)
{
used_all_subkeys = true;
break;
}
}
if (!used_all_subkeys)
{
switch (strat_total)
{
case BTLessStrategyNumber:
strat_total = BTLessEqualStrategyNumber;
break;
case BTGreaterStrategyNumber:
strat_total = BTGreaterEqualStrategyNumber;
break;
}
}
break; /* done with outer loop */
}
}
else
{
/*
* Ordinary comparison key. Transform the search-style scan key
* to an insertion scan key by replacing the sk_func with the
* appropriate btree comparison function.
*
* If scankey operator is not a cross-type comparison, we can use
* the cached comparison function; otherwise gotta look it up in
* the catalogs. (That can't lead to infinite recursion, since no
* indexscan initiated by syscache lookup will use cross-data-type
* operators.)
*
* We support the convention that sk_subtype == InvalidOid means
* the opclass input type; this is a hack to simplify life for
* ScanKeyInit().
*/
if (cur->sk_subtype == rel->rd_opcintype[i] ||
cur->sk_subtype == InvalidOid)
{
FmgrInfo *procinfo;
procinfo = index_getprocinfo(rel, cur->sk_attno, BTORDER_PROC);
ScanKeyEntryInitializeWithInfo(scankeys + i,
cur->sk_flags,
cur->sk_attno,
InvalidStrategy,
cur->sk_subtype,
cur->sk_collation,
procinfo,
cur->sk_argument);
}
else
{
RegProcedure cmp_proc;
cmp_proc = get_opfamily_proc(rel->rd_opfamily[i],
rel->rd_opcintype[i],
cur->sk_subtype,
BTORDER_PROC);
if (!RegProcedureIsValid(cmp_proc))
elog(ERROR, "missing support function %d(%u,%u) for attribute %d of index \"%s\"",
BTORDER_PROC, rel->rd_opcintype[i], cur->sk_subtype,
cur->sk_attno, RelationGetRelationName(rel));
ScanKeyEntryInitialize(scankeys + i,
cur->sk_flags,
cur->sk_attno,
InvalidStrategy,
cur->sk_subtype,
cur->sk_collation,
cmp_proc,
cur->sk_argument);
}
}
}
/*----------
* Examine the selected initial-positioning strategy to determine exactly
* where we need to start the scan, and set flag variables to control the
* code below.
*
* If nextkey = false, _bt_search and _bt_binsrch will locate the first
* item >= scan key. If nextkey = true, they will locate the first
* item > scan key.
*
* If goback = true, we will then step back one item, while if
* goback = false, we will start the scan on the located item.
*----------
*/
switch (strat_total)
{
case BTLessStrategyNumber:
/*
* Find first item >= scankey, then back up one to arrive at last
* item < scankey. (Note: this positioning strategy is only used
* for a backward scan, so that is always the correct starting
* position.)
*/
nextkey = false;
goback = true;
break;
case BTLessEqualStrategyNumber:
/*
* Find first item > scankey, then back up one to arrive at last
* item <= scankey. (Note: this positioning strategy is only used
* for a backward scan, so that is always the correct starting
* position.)
*/
nextkey = true;
goback = true;
break;
case BTEqualStrategyNumber:
/*
* If a backward scan was specified, need to start with last equal
* item not first one.
*/
if (ScanDirectionIsBackward(dir))
{
/*
* This is the same as the <= strategy. We will check at the
* end whether the found item is actually =.
*/
nextkey = true;
goback = true;
}
else
{
/*
* This is the same as the >= strategy. We will check at the
* end whether the found item is actually =.
*/
nextkey = false;
goback = false;
}
break;
case BTGreaterEqualStrategyNumber:
/*
* Find first item >= scankey. (This is only used for forward
* scans.)
*/
nextkey = false;
goback = false;
break;
case BTGreaterStrategyNumber:
/*
* Find first item > scankey. (This is only used for forward
* scans.)
*/
nextkey = true;
goback = false;
break;
default:
/* can't get here, but keep compiler quiet */
elog(ERROR, "unrecognized strat_total: %d", (int) strat_total);
return false;
}
/*
* Use the manufactured insertion scan key to descend the tree and
* position ourselves on the target leaf page.
*/
stack = _bt_search(rel, keysCount, scankeys, nextkey, &buf, BT_READ);
/* don't need to keep the stack around... */
_bt_freestack(stack);
/* remember which buffer we have pinned, if any */
so->currPos.buf = buf;
if (!BufferIsValid(buf))
{
/*
* We only get here if the index is completely empty. Lock relation
* because nothing finer to lock exists.
*/
PredicateLockRelation(rel, scan->xs_snapshot);
return false;
}
else
PredicateLockPage(rel, BufferGetBlockNumber(buf),
scan->xs_snapshot);
/* initialize moreLeft/moreRight appropriately for scan direction */
if (ScanDirectionIsForward(dir))
{
so->currPos.moreLeft = false;
so->currPos.moreRight = true;
}
else
{
so->currPos.moreLeft = true;
so->currPos.moreRight = false;
}
so->numKilled = 0; /* just paranoia */
so->markItemIndex = -1; /* ditto */
/* position to the precise item on the page */
offnum = _bt_binsrch(rel, buf, keysCount, scankeys, nextkey);
/*
* If nextkey = false, we are positioned at the first item >= scan key, or
* possibly at the end of a page on which all the existing items are less
* than the scan key and we know that everything on later pages is greater
* than or equal to scan key.
*
* If nextkey = true, we are positioned at the first item > scan key, or
* possibly at the end of a page on which all the existing items are less
* than or equal to the scan key and we know that everything on later
* pages is greater than scan key.
*
* The actually desired starting point is either this item or the prior
* one, or in the end-of-page case it's the first item on the next page or
* the last item on this page. Adjust the starting offset if needed. (If
* this results in an offset before the first item or after the last one,
* _bt_readpage will report no items found, and then we'll step to the
* next page as needed.)
*/
if (goback)
offnum = OffsetNumberPrev(offnum);
/*
* Now load data from the first page of the scan.
*/
if (!_bt_readpage(scan, dir, offnum))
{
/*
* There's no actually-matching data on this page. Try to advance to
* the next page. Return false if there's no matching data at all.
*/
if (!_bt_steppage(scan, dir))
return false;
}
/* Drop the lock, but not pin, on the current page */
LockBuffer(so->currPos.buf, BUFFER_LOCK_UNLOCK);
/* OK, itemIndex says what to return */
currItem = &so->currPos.items[so->currPos.itemIndex];
scan->xs_ctup.t_self = currItem->heapTid;
if (scan->xs_want_itup)
scan->xs_itup = (IndexTuple) (so->currTuples + currItem->tupleOffset);
return true;
}
/*
* make_scalar_array_op()
* Build expression tree for "scalar op ANY/ALL (array)" construct.
*/
Expr *
make_scalar_array_op(ParseState *pstate, List *opname,
bool useOr,
Node *ltree, Node *rtree,
int location)
{
Oid ltypeId,
rtypeId,
atypeId,
res_atypeId;
Operator tup;
Form_pg_operator opform;
Oid actual_arg_types[2];
Oid declared_arg_types[2];
List *args;
Oid rettype;
ScalarArrayOpExpr *result;
ltypeId = exprType(ltree);
atypeId = exprType(rtree);
/*
* The right-hand input of the operator will be the element type of the
* array. However, if we currently have just an untyped literal on the
* right, stay with that and hope we can resolve the operator.
*/
if (atypeId == UNKNOWNOID)
rtypeId = UNKNOWNOID;
else
{
rtypeId = get_base_element_type(atypeId);
if (!OidIsValid(rtypeId))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("op ANY/ALL (array) requires array on right side"),
parser_errposition(pstate, location)));
}
/* Now resolve the operator */
tup = oper(pstate, opname, ltypeId, rtypeId, false, location);
opform = (Form_pg_operator) GETSTRUCT(tup);
/* Check it's not a shell */
if (!RegProcedureIsValid(opform->oprcode))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("operator is only a shell: %s",
op_signature_string(opname,
opform->oprkind,
opform->oprleft,
opform->oprright)),
parser_errposition(pstate, location)));
args = list_make2(ltree, rtree);
actual_arg_types[0] = ltypeId;
actual_arg_types[1] = rtypeId;
declared_arg_types[0] = opform->oprleft;
declared_arg_types[1] = opform->oprright;
/*
* enforce consistency with polymorphic argument and return types,
* possibly adjusting return type or declared_arg_types (which will be
* used as the cast destination by make_fn_arguments)
*/
rettype = enforce_generic_type_consistency(actual_arg_types,
declared_arg_types,
2,
opform->oprresult,
false);
/*
* Check that operator result is boolean
*/
if (rettype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("op ANY/ALL (array) requires operator to yield boolean"),
parser_errposition(pstate, location)));
if (get_func_retset(opform->oprcode))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("op ANY/ALL (array) requires operator not to return a set"),
parser_errposition(pstate, location)));
/*
* Now switch back to the array type on the right, arranging for any
* needed cast to be applied. Beware of polymorphic operators here;
* enforce_generic_type_consistency may or may not have replaced a
* polymorphic type with a real one.
*/
if (IsPolymorphicType(declared_arg_types[1]))
{
/* assume the actual array type is OK */
res_atypeId = atypeId;
}
else
{
res_atypeId = get_array_type(declared_arg_types[1]);
if (!OidIsValid(res_atypeId))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(declared_arg_types[1])),
parser_errposition(pstate, location)));
}
actual_arg_types[1] = atypeId;
declared_arg_types[1] = res_atypeId;
/* perform the necessary typecasting of arguments */
make_fn_arguments(pstate, args, actual_arg_types, declared_arg_types);
/* and build the expression node */
result = makeNode(ScalarArrayOpExpr);
result->opno = oprid(tup);
result->opfuncid = opform->oprcode;
result->useOr = useOr;
/* inputcollid will be set by parse_collate.c */
result->args = args;
result->location = location;
ReleaseSysCache(tup);
return (Expr *) result;
}
/*
* make_op()
* Operator expression construction.
*
* Transform operator expression ensuring type compatibility.
* This is where some type conversion happens.
*
* As with coerce_type, pstate may be NULL if no special unknown-Param
* processing is wanted.
*/
Expr *
make_op(ParseState *pstate, List *opname, Node *ltree, Node *rtree,
int location)
{
Oid ltypeId,
rtypeId;
Operator tup;
Form_pg_operator opform;
Oid actual_arg_types[2];
Oid declared_arg_types[2];
int nargs;
List *args;
Oid rettype;
OpExpr *result;
/* Select the operator */
if (rtree == NULL)
{
/* right operator */
ltypeId = exprType(ltree);
rtypeId = InvalidOid;
tup = right_oper(pstate, opname, ltypeId, false, location);
}
else if (ltree == NULL)
{
/* left operator */
rtypeId = exprType(rtree);
ltypeId = InvalidOid;
tup = left_oper(pstate, opname, rtypeId, false, location);
}
else
{
/* otherwise, binary operator */
ltypeId = exprType(ltree);
rtypeId = exprType(rtree);
tup = oper(pstate, opname, ltypeId, rtypeId, false, location);
}
opform = (Form_pg_operator) GETSTRUCT(tup);
/* Check it's not a shell */
if (!RegProcedureIsValid(opform->oprcode))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("operator is only a shell: %s",
op_signature_string(opname,
opform->oprkind,
opform->oprleft,
opform->oprright)),
parser_errposition(pstate, location)));
/* Do typecasting and build the expression tree */
if (rtree == NULL)
{
/* right operator */
args = list_make1(ltree);
actual_arg_types[0] = ltypeId;
declared_arg_types[0] = opform->oprleft;
nargs = 1;
}
else if (ltree == NULL)
{
/* left operator */
args = list_make1(rtree);
actual_arg_types[0] = rtypeId;
declared_arg_types[0] = opform->oprright;
nargs = 1;
}
else
{
/* otherwise, binary operator */
args = list_make2(ltree, rtree);
actual_arg_types[0] = ltypeId;
actual_arg_types[1] = rtypeId;
declared_arg_types[0] = opform->oprleft;
declared_arg_types[1] = opform->oprright;
nargs = 2;
}
/*
* enforce consistency with polymorphic argument and return types,
* possibly adjusting return type or declared_arg_types (which will be
* used as the cast destination by make_fn_arguments)
*/
rettype = enforce_generic_type_consistency(actual_arg_types,
declared_arg_types,
nargs,
opform->oprresult,
false);
/* perform the necessary typecasting of arguments */
make_fn_arguments(pstate, args, actual_arg_types, declared_arg_types);
/* and build the expression node */
result = makeNode(OpExpr);
result->opno = oprid(tup);
result->opfuncid = opform->oprcode;
result->opresulttype = rettype;
result->opretset = get_func_retset(opform->oprcode);
/* opcollid and inputcollid will be set by parse_collate.c */
result->args = args;
result->location = location;
ReleaseSysCache(tup);
return (Expr *) result;
}
/*
* Compare two scankey values using a specified operator. Both values
* must be already known non-NULL.
*
* The test we want to perform is logically "leftarg op rightarg", where
* leftarg and rightarg are the sk_argument values in those ScanKeys, and
* the comparison operator is the one in the op ScanKey. However, in
* cross-data-type situations we may need to look up the correct operator in
* the index's opfamily: it is the one having amopstrategy = op->sk_strategy
* and amoplefttype/amoprighttype equal to the two argument datatypes.
*
* If the opfamily doesn't supply a complete set of cross-type operators we
* may not be able to make the comparison. If we can make the comparison
* we store the operator result in *result and return TRUE. We return FALSE
* if the comparison could not be made.
*
* Note: op always points at the same ScanKey as either leftarg or rightarg.
* Since we don't scribble on the scankeys, this aliasing should cause no
* trouble.
*
* Note: this routine needs to be insensitive to any DESC option applied
* to the index column. For example, "x < 4" is a tighter constraint than
* "x < 5" regardless of which way the index is sorted. We don't worry about
* NULLS FIRST/LAST either, since the given values are never nulls.
*/
static bool
_bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
ScanKey leftarg, ScanKey rightarg,
bool *result)
{
Relation rel = scan->indexRelation;
Oid lefttype,
righttype,
optype,
opcintype,
cmp_op;
StrategyNumber strat;
/*
* The opfamily we need to worry about is identified by the index column.
*/
Assert(leftarg->sk_attno == rightarg->sk_attno);
opcintype = rel->rd_opcintype[leftarg->sk_attno - 1];
/*
* Determine the actual datatypes of the ScanKey arguments. We have to
* support the convention that sk_subtype == InvalidOid means the opclass
* input type; this is a hack to simplify life for ScanKeyInit().
*/
lefttype = leftarg->sk_subtype;
if (lefttype == InvalidOid)
lefttype = opcintype;
righttype = rightarg->sk_subtype;
if (righttype == InvalidOid)
righttype = opcintype;
optype = op->sk_subtype;
if (optype == InvalidOid)
optype = opcintype;
/*
* If leftarg and rightarg match the types expected for the "op" scankey,
* we can use its already-looked-up comparison function.
*/
if (lefttype == opcintype && righttype == optype)
{
*result = DatumGetBool(FunctionCall2(&op->sk_func,
leftarg->sk_argument,
rightarg->sk_argument));
return true;
}
/*
* Otherwise, we need to go to the syscache to find the appropriate
* operator. (This cannot result in infinite recursion, since no
* indexscan initiated by syscache lookup will use cross-data-type
* operators.)
*
* If the sk_strategy was flipped by _bt_mark_scankey_with_indoption, we
* have to un-flip it to get the correct opfamily member.
*/
strat = op->sk_strategy;
if (op->sk_flags & SK_BT_DESC)
strat = BTCommuteStrategyNumber(strat);
cmp_op = get_opfamily_member(rel->rd_opfamily[leftarg->sk_attno - 1],
lefttype,
righttype,
strat);
if (OidIsValid(cmp_op))
{
RegProcedure cmp_proc = get_opcode(cmp_op);
if (RegProcedureIsValid(cmp_proc))
{
*result = DatumGetBool(OidFunctionCall2(cmp_proc,
leftarg->sk_argument,
rightarg->sk_argument));
return true;
}
}
/* Can't make the comparison */
*result = false; /* suppress compiler warnings */
return false;
}
/*
* Compare two scankey values using a specified operator.
*
* The test we want to perform is logically "leftarg op rightarg", where
* leftarg and rightarg are the sk_argument values in those ScanKeys, and
* the comparison operator is the one in the op ScanKey. However, in
* cross-data-type situations we may need to look up the correct operator in
* the index's opfamily: it is the one having amopstrategy = op->sk_strategy
* and amoplefttype/amoprighttype equal to the two argument datatypes.
*
* If the opfamily doesn't supply a complete set of cross-type operators we
* may not be able to make the comparison. If we can make the comparison
* we store the operator result in *result and return TRUE. We return FALSE
* if the comparison could not be made.
*
* Note: op always points at the same ScanKey as either leftarg or rightarg.
* Since we don't scribble on the scankeys, this aliasing should cause no
* trouble.
*
* Note: this routine needs to be insensitive to any DESC option applied
* to the index column. For example, "x < 4" is a tighter constraint than
* "x < 5" regardless of which way the index is sorted.
*/
static bool
_bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
ScanKey leftarg, ScanKey rightarg,
bool *result)
{
Relation rel = scan->indexRelation;
Oid lefttype,
righttype,
optype,
opcintype,
cmp_op;
StrategyNumber strat;
/*
* First, deal with cases where one or both args are NULL. This should
* only happen when the scankeys represent IS NULL/NOT NULL conditions.
*/
if ((leftarg->sk_flags | rightarg->sk_flags) & SK_ISNULL)
{
bool leftnull,
rightnull;
if (leftarg->sk_flags & SK_ISNULL)
{
Assert(leftarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
leftnull = true;
}
else
leftnull = false;
if (rightarg->sk_flags & SK_ISNULL)
{
Assert(rightarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
rightnull = true;
}
else
rightnull = false;
/*
* We treat NULL as either greater than or less than all other values.
* Since true > false, the tests below work correctly for NULLS LAST
* logic. If the index is NULLS FIRST, we need to flip the strategy.
*/
strat = op->sk_strategy;
if (op->sk_flags & SK_BT_NULLS_FIRST)
strat = BTCommuteStrategyNumber(strat);
switch (strat)
{
case BTLessStrategyNumber:
*result = (leftnull < rightnull);
break;
case BTLessEqualStrategyNumber:
*result = (leftnull <= rightnull);
break;
case BTEqualStrategyNumber:
*result = (leftnull == rightnull);
break;
case BTGreaterEqualStrategyNumber:
*result = (leftnull >= rightnull);
break;
case BTGreaterStrategyNumber:
*result = (leftnull > rightnull);
break;
default:
elog(ERROR, "unrecognized StrategyNumber: %d", (int) strat);
*result = false; /* keep compiler quiet */
break;
}
return true;
}
/*
* The opfamily we need to worry about is identified by the index column.
*/
Assert(leftarg->sk_attno == rightarg->sk_attno);
opcintype = rel->rd_opcintype[leftarg->sk_attno - 1];
/*
* Determine the actual datatypes of the ScanKey arguments. We have to
* support the convention that sk_subtype == InvalidOid means the opclass
* input type; this is a hack to simplify life for ScanKeyInit().
*/
lefttype = leftarg->sk_subtype;
if (lefttype == InvalidOid)
lefttype = opcintype;
righttype = rightarg->sk_subtype;
if (righttype == InvalidOid)
righttype = opcintype;
optype = op->sk_subtype;
if (optype == InvalidOid)
optype = opcintype;
/*
* If leftarg and rightarg match the types expected for the "op" scankey,
* we can use its already-looked-up comparison function.
*/
if (lefttype == opcintype && righttype == optype)
{
*result = DatumGetBool(FunctionCall2Coll(&op->sk_func,
op->sk_collation,
leftarg->sk_argument,
rightarg->sk_argument));
return true;
}
/*
* Otherwise, we need to go to the syscache to find the appropriate
* operator. (This cannot result in infinite recursion, since no
* indexscan initiated by syscache lookup will use cross-data-type
* operators.)
*
* If the sk_strategy was flipped by _bt_fix_scankey_strategy, we have to
* un-flip it to get the correct opfamily member.
*/
strat = op->sk_strategy;
if (op->sk_flags & SK_BT_DESC)
strat = BTCommuteStrategyNumber(strat);
cmp_op = get_opfamily_member(rel->rd_opfamily[leftarg->sk_attno - 1],
lefttype,
righttype,
strat);
if (OidIsValid(cmp_op))
{
RegProcedure cmp_proc = get_opcode(cmp_op);
if (RegProcedureIsValid(cmp_proc))
{
*result = DatumGetBool(OidFunctionCall2Coll(cmp_proc,
op->sk_collation,
leftarg->sk_argument,
rightarg->sk_argument));
return true;
}
}
/* Can't make the comparison */
*result = false; /* suppress compiler warnings */
return false;
}