예제 #1
0
/*
 * Accept one tuple and append it to the tuplestore.
 *
 * Note that the input tuple is always copied; the caller need not save it.
 *
 * If the active read pointer is currently "at EOF", it remains so (the read
 * pointer implicitly advances along with the write pointer); otherwise the
 * read pointer is unchanged.  Non-active read pointers do not move, which
 * means they are certain to not be "at EOF" immediately after puttuple.
 * This curious-seeming behavior is for the convenience of nodeMaterial.c and
 * nodeCtescan.c, which would otherwise need to do extra pointer repositioning
 * steps.
 *
 * tuplestore_puttupleslot() is a convenience routine to collect data from
 * a TupleTableSlot without an extra copy operation.
 */
void
tuplestore_puttupleslot(Tuplestorestate *state,
						TupleTableSlot *slot)
{
	MinimalTuple tuple;

	/*
	 * Form a MinimalTuple in working memory
	 */
	tuple = ExecCopySlotMinimalTuple(slot);
	USEMEM(state, GetMemoryChunkSpace(tuple));

	tuplestore_puttuple_common(state, (void *) tuple);
}
예제 #2
0
/*
 * Find or create a hashtable entry for the tuple group containing the
 * given tuple.  The tuple must be the same type as the hashtable entries.
 *
 * If isnew is NULL, we do not create new entries; we return NULL if no
 * match is found.
 *
 * If isnew isn't NULL, then a new entry is created if no existing entry
 * matches.  On return, *isnew is true if the entry is newly created,
 * false if it existed already.  ->additional_data in the new entry has
 * been zeroed.
 */
TupleHashEntry
LookupTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
					 bool *isnew)
{
	TupleHashEntryData *entry;
	MemoryContext oldContext;
	bool		found;
	MinimalTuple key;

	/* Need to run the hash functions in short-lived context */
	oldContext = MemoryContextSwitchTo(hashtable->tempcxt);

	/* set up data needed by hash and match functions */
	hashtable->inputslot = slot;
	hashtable->in_hash_funcs = hashtable->tab_hash_funcs;
	hashtable->cur_eq_func = hashtable->tab_eq_func;

	key = NULL;					/* flag to reference inputslot */

	if (isnew)
	{
		entry = tuplehash_insert(hashtable->hashtab, key, &found);

		if (found)
		{
			/* found pre-existing entry */
			*isnew = false;
		}
		else
		{
			/* created new entry */
			*isnew = true;
			/* zero caller data */
			entry->additional = NULL;
			MemoryContextSwitchTo(hashtable->tablecxt);
			/* Copy the first tuple into the table context */
			entry->firstTuple = ExecCopySlotMinimalTuple(slot);
		}
	}
	else
	{
		entry = tuplehash_lookup(hashtable->hashtab, key);
	}

	MemoryContextSwitchTo(oldContext);

	return entry;
}
예제 #3
0
/*
 * Find or create a hashtable entry for the tuple group containing the
 * given tuple.  The tuple must be the same type as the hashtable entries.
 *
 * If isnew is NULL, we do not create new entries; we return NULL if no
 * match is found.
 *
 * If isnew isn't NULL, then a new entry is created if no existing entry
 * matches.  On return, *isnew is true if the entry is newly created,
 * false if it existed already.  ->additional_data in the new entry has
 * been zeroed.
 */
TupleHashEntry
LookupTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
					 bool *isnew)
{
	TupleHashEntryData *entry;
	MemoryContext oldContext;
	bool		found;
	MinimalTuple key;

	/* If first time through, clone the input slot to make table slot */
	if (hashtable->tableslot == NULL)
	{
		TupleDesc	tupdesc;

		oldContext = MemoryContextSwitchTo(hashtable->tablecxt);

		/*
		 * We copy the input tuple descriptor just for safety --- we assume
		 * all input tuples will have equivalent descriptors.
		 */
		tupdesc = CreateTupleDescCopy(slot->tts_tupleDescriptor);
		hashtable->tableslot = MakeSingleTupleTableSlot(tupdesc);
		MemoryContextSwitchTo(oldContext);
	}

	/* Need to run the hash functions in short-lived context */
	oldContext = MemoryContextSwitchTo(hashtable->tempcxt);

	/* set up data needed by hash and match functions */
	hashtable->inputslot = slot;
	hashtable->in_hash_funcs = hashtable->tab_hash_funcs;
	hashtable->cur_eq_funcs = hashtable->tab_eq_funcs;

	key = NULL; /* flag to reference inputslot */

	if (isnew)
	{
		entry = tuplehash_insert(hashtable->hashtab, key, &found);

		if (found)
		{
			/* found pre-existing entry */
			*isnew = false;
		}
		else
		{
			/* created new entry */
			*isnew = true;
			/* zero caller data */
			entry->additional = NULL;
			MemoryContextSwitchTo(hashtable->tablecxt);
			/* Copy the first tuple into the table context */
			entry->firstTuple = ExecCopySlotMinimalTuple(slot);
		}
	}
	else
	{
		entry = tuplehash_lookup(hashtable->hashtab, key);
	}

	MemoryContextSwitchTo(oldContext);

	return entry;
}
예제 #4
0
/*
 * Find or create a hashtable entry for the tuple group containing the
 * given tuple.
 *
 * If isnew is NULL, we do not create new entries; we return NULL if no
 * match is found.
 *
 * If isnew isn't NULL, then a new entry is created if no existing entry
 * matches.  On return, *isnew is true if the entry is newly created,
 * false if it existed already.  Any extra space in a new entry has been
 * zeroed.
 */
TupleHashEntry
LookupTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
					 bool *isnew)
{
	TupleHashEntry entry;
	MemoryContext oldContext;
	TupleHashTable saveCurHT;
	TupleHashEntryData dummy;
	bool		found;

	/* If first time through, clone the input slot to make table slot */
	if (hashtable->tableslot == NULL)
	{
		TupleDesc	tupdesc;

		oldContext = MemoryContextSwitchTo(hashtable->tablecxt);

		/*
		 * We copy the input tuple descriptor just for safety --- we assume
		 * all input tuples will have equivalent descriptors.
		 */
		tupdesc = CreateTupleDescCopy(slot->tts_tupleDescriptor);
		hashtable->tableslot = MakeSingleTupleTableSlot(tupdesc);
		MemoryContextSwitchTo(oldContext);
	}

	/* Need to run the hash functions in short-lived context */
	oldContext = MemoryContextSwitchTo(hashtable->tempcxt);

	/*
	 * Set up data needed by hash and match functions
	 *
	 * We save and restore CurTupleHashTable just in case someone manages to
	 * invoke this code re-entrantly.
	 */
	hashtable->inputslot = slot;
	saveCurHT = CurTupleHashTable;
	CurTupleHashTable = hashtable;

	/* Search the hash table */
	dummy.firstTuple = NULL;	/* flag to reference inputslot */
	entry = (TupleHashEntry) hash_search(hashtable->hashtab,
										 &dummy,
										 isnew ? HASH_ENTER : HASH_FIND,
										 &found);

	if (isnew)
	{
		if (found)
		{
			/* found pre-existing entry */
			*isnew = false;
		}
		else
		{
			/*
			 * created new entry
			 *
			 * Zero any caller-requested space in the entry.  (This zaps the
			 * "key data" dynahash.c copied into the new entry, but we don't
			 * care since we're about to overwrite it anyway.)
			 */
			MemSet(entry, 0, hashtable->entrysize);
			/* Copy the first tuple into the table context */
			MemoryContextSwitchTo(hashtable->tablecxt);
			entry->firstTuple = ExecCopySlotMinimalTuple(slot);


			*isnew = true;
		}
	}

	CurTupleHashTable = saveCurHT;

	MemoryContextSwitchTo(oldContext);

	return entry;
}