Function build_inserttuple

src/backend/access/bitmap/bitmapinsert.c:2278–2412

* build_inserttuple() -- insert a new tuple into the bitmap index * during the bitmap index construction. * * Each new tuple has an assigned number -- tidnum, called a * tid location, which represents the bit location for this tuple in * a bitmap vector. To speed up the construction, this function does not * write this tid location into its bitmap vector immediately. We maintain * a buffer

 * for enough distinct values to disk to accommodate this new tuple.
 */
static void
build_inserttuple(Relation rel, uint64 tidnum,
				  ItemPointerData ht_ctid  pg_attribute_unused(), TupleDesc tupDesc,
				  Datum *attdata, bool *nulls, BMBuildState *state)
{
	Buffer 			metabuf;
	BlockNumber		lovBlock;
	OffsetNumber	lovOffset;
	bool			blockNull;
	bool			offsetNull;
	BMTidBuildBuf *tidLocsBuffer;
	int				attno;
	bool			allNulls = true;
	BMBuildHashKey  *entry;

	CHECK_FOR_INTERRUPTS();

	tidLocsBuffer = state->bm_tidLocsBuffer;

	/* Check if all attributes have value of NULL. */
	for (attno = 0; attno < tupDesc->natts; attno++)
	{
		if (!nulls[attno])
		{
			allNulls = false;
			break;
		}
	}

	metabuf = _bitmap_getbuf(rel, BM_METAPAGE, BM_WRITE);
	
	/*
	 * if the inserting tuple has the value of NULL, then
	 * the corresponding tid array is the first.
	 */
	if (allNulls)
	{
		lovBlock = BM_LOV_STARTPAGE;
		lovOffset = 1;
	}
	else
	{
		bool found;
		BMBuildLovData *lov;

		if (state->lovitem_hash)
		{
		    BMBuildHashKey toLookup;
		    toLookup.attributeValueArr = attdata;
		    toLookup.isNullArr = nulls;

			/* look up the hash to see if we can find the lov data that way */
			entry = (BMBuildHashKey *)hash_search(state->lovitem_hash,
												  (void*)&toLookup,
												  HASH_ENTER, &found);
			if (!found)
			{
				/* Copy the key values in case someone modifies them */