/*
* See whether two tuples (presumably of the same hash value) match
*
* As above, the passed pointers are pointers to TupleHashEntryData.
*
* Also, the caller must select an appropriate memory context for running
* the compare functions. (dynahash.c doesn't change CurrentMemoryContext.)
*/
static int
TupleHashTableMatch(struct tuplehash_hash *tb, const MinimalTuple tuple1, const MinimalTuple tuple2)
{
TupleTableSlot *slot1;
TupleTableSlot *slot2;
TupleHashTable hashtable = (TupleHashTable) tb->private_data;
/*
* We assume that simplehash.h will only ever call us with the first
* argument being an actual table entry, and the second argument being
* LookupTupleHashEntry's dummy TupleHashEntryData. The other direction
* could be supported too, but is not currently required.
*/
Assert(tuple1 != NULL);
slot1 = hashtable->tableslot;
ExecStoreMinimalTuple(tuple1, slot1, false);
Assert(tuple2 == NULL);
slot2 = hashtable->inputslot;
/* For crosstype comparisons, the inputslot must be first */
if (execTuplesMatch(slot2,
slot1,
hashtable->numCols,
hashtable->keyColIdx,
hashtable->cur_eq_funcs,
hashtable->tempcxt))
return 0;
else
return 1;
}
/*
* tuplestore_gettupleslot - exported function to fetch a MinimalTuple
*
* If successful, put tuple in slot and return TRUE; else, clear the slot
* and return FALSE.
*
* If copy is TRUE, the slot receives a copied tuple (allocated in current
* memory context) that will stay valid regardless of future manipulations of
* the tuplestore's state. If copy is FALSE, the slot may just receive a
* pointer to a tuple held within the tuplestore. The latter is more
* efficient but the slot contents may be corrupted if additional writes to
* the tuplestore occur. (If using tuplestore_trim, see comments therein.)
*/
bool
tuplestore_gettupleslot(Tuplestorestate *state, bool forward,
bool copy, TupleTableSlot *slot)
{
MinimalTuple tuple;
bool should_free;
tuple = (MinimalTuple) tuplestore_gettuple(state, forward, &should_free);
if (tuple)
{
if (copy && !should_free)
{
tuple = heap_copy_minimal_tuple(tuple);
should_free = true;
}
ExecStoreMinimalTuple(tuple, slot, should_free);
return true;
}
else
{
ExecClearTuple(slot);
return false;
}
}
/*
* See whether two tuples (presumably of the same hash value) match
*
* As above, the passed pointers are pointers to TupleHashEntryData.
*
* CurTupleHashTable must be set before calling this, since dynahash.c
* doesn't provide any API that would let us get at the hashtable otherwise.
*
* Also, the caller must select an appropriate memory context for running
* the compare functions. (dynahash.c doesn't change CurrentMemoryContext.)
*/
static int
TupleHashTableMatch(const void *key1, const void *key2, Size keysize)
{
MinimalTuple tuple1 = ((const TupleHashEntryData *) key1)->firstTuple;
#ifdef USE_ASSERT_CHECKING
MinimalTuple tuple2 = ((const TupleHashEntryData *) key2)->firstTuple;
#endif
TupleTableSlot *slot1;
TupleTableSlot *slot2;
TupleHashTable hashtable = CurTupleHashTable;
/*
* We assume that dynahash.c will only ever call us with the first
* argument being an actual table entry, and the second argument being
* LookupTupleHashEntry's dummy TupleHashEntryData. The other direction
* could be supported too, but is not currently used by dynahash.c.
*/
Assert(tuple1 != NULL);
slot1 = hashtable->tableslot;
ExecStoreMinimalTuple(tuple1, slot1, false);
Assert(tuple2 == NULL);
slot2 = hashtable->inputslot;
if (execTuplesMatch(slot1,
slot2,
hashtable->numCols,
hashtable->keyColIdx,
hashtable->eqfunctions,
hashtable->tempcxt))
return 0;
else
return 1;
}
/*
* See whether two tuples (presumably of the same hash value) match
*
* As above, the passed pointers are pointers to TupleHashEntryData.
*/
static int
TupleHashTableMatch(struct tuplehash_hash *tb, const MinimalTuple tuple1, const MinimalTuple tuple2)
{
TupleTableSlot *slot1;
TupleTableSlot *slot2;
TupleHashTable hashtable = (TupleHashTable) tb->private_data;
ExprContext *econtext = hashtable->exprcontext;
/*
* We assume that simplehash.h will only ever call us with the first
* argument being an actual table entry, and the second argument being
* LookupTupleHashEntry's dummy TupleHashEntryData. The other direction
* could be supported too, but is not currently required.
*/
Assert(tuple1 != NULL);
slot1 = hashtable->tableslot;
ExecStoreMinimalTuple(tuple1, slot1, false);
Assert(tuple2 == NULL);
slot2 = hashtable->inputslot;
/* For crosstype comparisons, the inputslot must be first */
econtext->ecxt_innertuple = slot2;
econtext->ecxt_outertuple = slot1;
return !ExecQualAndReset(hashtable->cur_eq_func, econtext);
}
/*
* Compute the hash value for a tuple
*
* The passed-in key is a pointer to TupleHashEntryData. In an actual hash
* table entry, the firstTuple field points to a tuple (in MinimalTuple
* format). LookupTupleHashEntry sets up a dummy TupleHashEntryData with a
* NULL firstTuple field --- that cues us to look at the inputslot instead.
* This convention avoids the need to materialize virtual input tuples unless
* they actually need to get copied into the table.
*
* Also, the caller must select an appropriate memory context for running
* the hash functions. (dynahash.c doesn't change CurrentMemoryContext.)
*/
static uint32
TupleHashTableHash(struct tuplehash_hash *tb, const MinimalTuple tuple)
{
TupleHashTable hashtable = (TupleHashTable) tb->private_data;
int numCols = hashtable->numCols;
AttrNumber *keyColIdx = hashtable->keyColIdx;
uint32 hashkey = hashtable->hash_iv;
TupleTableSlot *slot;
FmgrInfo *hashfunctions;
int i;
if (tuple == NULL)
{
/* Process the current input tuple for the table */
slot = hashtable->inputslot;
hashfunctions = hashtable->in_hash_funcs;
}
else
{
/*
* Process a tuple already stored in the table.
*
* (this case never actually occurs due to the way simplehash.h is
* used, as the hash-value is stored in the entries)
*/
slot = hashtable->tableslot;
ExecStoreMinimalTuple(tuple, slot, false);
hashfunctions = hashtable->tab_hash_funcs;
}
for (i = 0; i < numCols; i++)
{
AttrNumber att = keyColIdx[i];
Datum attr;
bool isNull;
/* rotate hashkey left 1 bit at each step */
hashkey = (hashkey << 1) | ((hashkey & 0x80000000) ? 1 : 0);
attr = slot_getattr(slot, att, &isNull);
if (!isNull) /* treat nulls as having hash key 0 */
{
uint32 hkey;
hkey = DatumGetUInt32(FunctionCall1(&hashfunctions[i],
attr));
hashkey ^= hkey;
}
}
/*
* The way hashes are combined above, among each other and with the IV,
* doesn't lead to good bit perturbation. As the IV's goal is to lead to
* achieve that, perform a round of hashing of the combined hash -
* resulting in near perfect perturbation.
*/
return murmurhash32(hashkey);
}
/*
* Compute the hash value for a tuple
*
* The passed-in key is a pointer to TupleHashEntryData. In an actual hash
* table entry, the firstTuple field points to a tuple (in MinimalTuple
* format). LookupTupleHashEntry sets up a dummy TupleHashEntryData with a
* NULL firstTuple field --- that cues us to look at the inputslot instead.
* This convention avoids the need to materialize virtual input tuples unless
* they actually need to get copied into the table.
*
* Also, the caller must select an appropriate memory context for running
* the hash functions. (dynahash.c doesn't change CurrentMemoryContext.)
*/
static uint32
TupleHashTableHash(struct tuplehash_hash *tb, const MinimalTuple tuple)
{
TupleHashTable hashtable = (TupleHashTable) tb->private_data;
int numCols = hashtable->numCols;
AttrNumber *keyColIdx = hashtable->keyColIdx;
uint32 hashkey = hashtable->hash_iv;
TupleTableSlot *slot;
FmgrInfo *hashfunctions;
int i;
if (tuple == NULL)
{
/* Process the current input tuple for the table */
slot = hashtable->inputslot;
hashfunctions = hashtable->in_hash_funcs;
}
else
{
/*
* Process a tuple already stored in the table.
*
* (this case never actually occurs due to the way simplehash.h is
* used, as the hash-value is stored in the entries)
*/
slot = hashtable->tableslot;
ExecStoreMinimalTuple(tuple, slot, false);
hashfunctions = hashtable->tab_hash_funcs;
}
for (i = 0; i < numCols; i++)
{
AttrNumber att = keyColIdx[i];
Datum attr;
bool isNull;
/* rotate hashkey left 1 bit at each step */
hashkey = (hashkey << 1) | ((hashkey & 0x80000000) ? 1 : 0);
attr = slot_getattr(slot, att, &isNull);
if (!isNull) /* treat nulls as having hash key 0 */
{
uint32 hkey;
hkey = DatumGetUInt32(FunctionCall1(&hashfunctions[i],
attr));
hashkey ^= hkey;
}
}
return hashkey;
}
/*
* Compute the hash value for a tuple
*
* The passed-in key is a pointer to TupleHashEntryData. In an actual hash
* table entry, the firstTuple field points to a tuple (in MinimalTuple
* format). LookupTupleHashEntry sets up a dummy TupleHashEntryData with a
* NULL firstTuple field --- that cues us to look at the inputslot instead.
* This convention avoids the need to materialize virtual input tuples unless
* they actually need to get copied into the table.
*
* CurTupleHashTable must be set before calling this, since dynahash.c
* doesn't provide any API that would let us get at the hashtable otherwise.
*
* Also, the caller must select an appropriate memory context for running
* the hash functions. (dynahash.c doesn't change CurrentMemoryContext.)
*/
static uint32
TupleHashTableHash(const void *key, Size keysize)
{
MinimalTuple tuple = ((const TupleHashEntryData *) key)->firstTuple;
TupleTableSlot *slot;
TupleHashTable hashtable = CurTupleHashTable;
int numCols = hashtable->numCols;
AttrNumber *keyColIdx = hashtable->keyColIdx;
FmgrInfo *hashfunctions;
uint32 hashkey = 0;
int i;
if (tuple == NULL)
{
/* Process the current input tuple for the table */
slot = hashtable->inputslot;
hashfunctions = hashtable->in_hash_funcs;
}
else
{
/* Process a tuple already stored in the table */
/* (this case never actually occurs in current dynahash.c code) */
slot = hashtable->tableslot;
ExecStoreMinimalTuple(tuple, slot, false);
hashfunctions = hashtable->tab_hash_funcs;
}
for (i = 0; i < numCols; i++)
{
AttrNumber att = keyColIdx[i];
Datum attr;
bool isNull;
/* rotate hashkey left 1 bit at each step */
hashkey = (hashkey << 1) | ((hashkey & 0x80000000) ? 1 : 0);
attr = slot_getattr(slot, att, &isNull);
if (!isNull) /* treat nulls as having hash key 0 */
{
uint32 hkey;
hkey = DatumGetUInt32(FunctionCall1(&hashfunctions[i],
attr));
hashkey ^= hkey;
}
}
return hashkey;
}
/*
* ExecSetOp for hashed case: phase 2, retrieving groups from hash table
*/
static TupleTableSlot *
setop_retrieve_hash_table(SetOpState *setopstate)
{
TupleHashEntryData *entry;
TupleTableSlot *resultTupleSlot;
/*
* get state info from node
*/
resultTupleSlot = setopstate->ps.ps_ResultTupleSlot;
/*
* We loop retrieving groups until we find one we should return
*/
while (!setopstate->setop_done)
{
CHECK_FOR_INTERRUPTS();
/*
* Find the next entry in the hash table
*/
entry = ScanTupleHashTable(setopstate->hashtable, &setopstate->hashiter);
if (entry == NULL)
{
/* No more entries in hashtable, so done */
setopstate->setop_done = true;
return NULL;
}
/*
* See if we should emit any copies of this tuple, and if so return
* the first copy.
*/
set_output_count(setopstate, (SetOpStatePerGroup) entry->additional);
if (setopstate->numOutput > 0)
{
setopstate->numOutput--;
return ExecStoreMinimalTuple(entry->firstTuple,
resultTupleSlot,
false);
}
}
/* No more groups */
ExecClearTuple(resultTupleSlot);
return NULL;
}
/*
* tuplestore_gettupleslot - exported function to fetch a MinimalTuple
*
* If successful, put tuple in slot and return TRUE; else, clear the slot
* and return FALSE.
*/
bool
tuplestore_gettupleslot_pos(Tuplestorestate *state, TuplestorePos *pos, bool forward,
TupleTableSlot *slot)
{
MemTuple tuple;
bool should_free = false;
tuple = (MemTuple) tuplestore_gettuple(state, pos, forward, &should_free);
if (tuple)
{
ExecStoreMinimalTuple(tuple, slot, should_free);
return true;
}
else
{
ExecClearTuple(slot);
return false;
}
}
/* --------------------------------
* ExecStoreTuple
*
* This function is used to store a physical tuple into a specified
* slot in the tuple table.
*
* tuple: tuple to store
* slot: slot to store it in
* buffer: disk buffer if tuple is in a disk page, else InvalidBuffer
* shouldFree: true if ExecClearTuple should pfree() the tuple
* when done with it
*
* If 'buffer' is not InvalidBuffer, the tuple table code acquires a pin
* on the buffer which is held until the slot is cleared, so that the tuple
* won't go away on us.
*
* shouldFree is normally set 'true' for tuples constructed on-the-fly.
* It must always be 'false' for tuples that are stored in disk pages,
* since we don't want to try to pfree those.
*
* Another case where it is 'false' is when the referenced tuple is held
* in a tuple table slot belonging to a lower-level executor Proc node.
* In this case the lower-level slot retains ownership and responsibility
* for eventually releasing the tuple. When this method is used, we must
* be certain that the upper-level Proc node will lose interest in the tuple
* sooner than the lower-level one does! If you're not certain, copy the
* lower-level tuple with heap_copytuple and let the upper-level table
* slot assume ownership of the copy!
*
* Return value is just the passed-in slot pointer.
*
* NOTE: before PostgreSQL 8.1, this function would accept a NULL tuple
* pointer and effectively behave like ExecClearTuple (though you could
* still specify a buffer to pin, which would be an odd combination).
* This saved a couple lines of code in a few places, but seemed more likely
* to mask logic errors than to be really useful, so it's now disallowed.
* --------------------------------
*/
TupleTableSlot *
ExecStoreHeapTuple(HeapTuple tuple,
TupleTableSlot *slot,
Buffer buffer,
bool shouldFree)
{
/*
* sanity checks
*/
Assert(tuple != NULL);
Assert(slot != NULL);
Assert(slot->tts_tupleDescriptor != NULL);
/* passing shouldFree=true for a tuple on a disk page is not sane */
Assert(BufferIsValid(buffer) ? (!shouldFree) : true);
/*
* Actually we are storing a memtuple!
*/
if(is_heaptuple_memtuple(tuple))
{
Assert(buffer == InvalidBuffer);
return ExecStoreMinimalTuple((MemTuple) tuple, slot, shouldFree);
}
/*
* Free any old physical tuple belonging to the slot.
*/
free_heaptuple_memtuple(slot);
/*
* Store the new tuple into the specified slot.
*/
/* Clear tts_flags, here isempty set to false */
slot->PRIVATE_tts_flags = shouldFree ? TTS_SHOULDFREE : 0;
/* store the tuple */
slot->PRIVATE_tts_heaptuple = (void *) tuple;
/* Mark extracted state invalid */
slot->PRIVATE_tts_nvalid = 0;
/*
* If tuple is on a disk page, keep the page pinned as long as we hold a
* pointer into it. We assume the caller already has such a pin.
*
* This is coded to optimize the case where the slot previously held a
* tuple on the same disk page: in that case releasing and re-acquiring
* the pin is a waste of cycles. This is a common situation during
* seqscans, so it's worth troubling over.
*/
if (slot->tts_buffer != buffer)
{
if (BufferIsValid(slot->tts_buffer))
ReleaseBuffer(slot->tts_buffer);
slot->tts_buffer = buffer;
if (BufferIsValid(buffer))
IncrBufferRefCount(buffer);
}
return slot;
}
