Have crosstab variants treat NULL rowid as a category in its own right,

per suggestion from Tom Lane. This fixes crash-bug reported by Stefan
Schwarzer.

contrib/tablefunc/data/ct.data

@@ -12,3 +12,7 @@
 12	group2	test4	att1	val4
 13	group2	test4	att2	val5
 14	group2	test4	att3	val6
+15	group1	\N	att1	val9
+16	group1	\N	att2	val10
+17	group1	\N	att3	val11
+18	group1	\N	att4	val12

contrib/tablefunc/expected/tablefunc.out

@@ -23,42 +23,48 @@ SELECT * FROM crosstab2('SELECT rowid, attribute, val FROM ct where rowclass = '
 ----------+------------+------------
  test1    | val2       | val3
  test2    | val6       | val7
-(2 rows)
+          | val10      | val11
+(3 rows)
 
 SELECT * FROM crosstab3('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' and (attribute = ''att2'' or attribute = ''att3'') ORDER BY 1,2;');
  row_name | category_1 | category_2 | category_3 
 ----------+------------+------------+------------
  test1    | val2       | val3       | 
  test2    | val6       | val7       | 
-(2 rows)
+          | val10      | val11      | 
+(3 rows)
 
 SELECT * FROM crosstab4('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' and (attribute = ''att2'' or attribute = ''att3'') ORDER BY 1,2;');
  row_name | category_1 | category_2 | category_3 | category_4 
 ----------+------------+------------+------------+------------
  test1    | val2       | val3       |            | 
  test2    | val6       | val7       |            | 
-(2 rows)
+          | val10      | val11      |            | 
+(3 rows)
 
 SELECT * FROM crosstab2('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' ORDER BY 1,2;');
  row_name | category_1 | category_2 
 ----------+------------+------------
  test1    | val1       | val2
  test2    | val5       | val6
-(2 rows)
+          | val9       | val10
+(3 rows)
 
 SELECT * FROM crosstab3('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' ORDER BY 1,2;');
  row_name | category_1 | category_2 | category_3 
 ----------+------------+------------+------------
  test1    | val1       | val2       | val3
  test2    | val5       | val6       | val7
-(2 rows)
+          | val9       | val10      | val11
+(3 rows)
 
 SELECT * FROM crosstab4('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' ORDER BY 1,2;');
  row_name | category_1 | category_2 | category_3 | category_4 
 ----------+------------+------------+------------+------------
  test1    | val1       | val2       | val3       | val4
  test2    | val5       | val6       | val7       | val8
-(2 rows)
+          | val9       | val10      | val11      | val12
+(3 rows)
 
 SELECT * FROM crosstab2('SELECT rowid, attribute, val FROM ct where rowclass = ''group2'' and (attribute = ''att1'' or attribute = ''att2'') ORDER BY 1,2;');
  row_name | category_1 | category_2 
@@ -103,25 +109,28 @@ SELECT * FROM crosstab4('SELECT rowid, attribute, val FROM ct where rowclass = '
 (2 rows)
 
 SELECT * FROM crosstab('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' ORDER BY 1,2;') AS c(rowid text, att1 text, att2 text);
- rowid | att1 | att2 
--------+------+------
+ rowid | att1 | att2  
+-------+------+-------
  test1 | val1 | val2
  test2 | val5 | val6
-(2 rows)
+       | val9 | val10
+(3 rows)
 
 SELECT * FROM crosstab('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' ORDER BY 1,2;') AS c(rowid text, att1 text, att2 text, att3 text);
- rowid | att1 | att2 | att3 
--------+------+------+------
- test1 | val1 | val2 | val3
- test2 | val5 | val6 | val7
-(2 rows)
+ rowid | att1 | att2  | att3  
+-------+------+-------+-------
+ test1 | val1 | val2  | val3
+ test2 | val5 | val6  | val7
+       | val9 | val10 | val11
+(3 rows)
 
 SELECT * FROM crosstab('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' ORDER BY 1,2;') AS c(rowid text, att1 text, att2 text, att3 text, att4 text);
- rowid | att1 | att2 | att3 | att4 
--------+------+------+------+------
- test1 | val1 | val2 | val3 | val4
- test2 | val5 | val6 | val7 | val8
-(2 rows)
+ rowid | att1 | att2  | att3  | att4  
+-------+------+-------+-------+-------
+ test1 | val1 | val2  | val3  | val4
+ test2 | val5 | val6  | val7  | val8
+       | val9 | val10 | val11 | val12
+(3 rows)
 
 -- check it works with OUT parameters, too
 CREATE FUNCTION crosstab_out(text,
@@ -130,11 +139,12 @@ RETURNS setof record
 AS '$libdir/tablefunc','crosstab'
 LANGUAGE C STABLE STRICT;
 SELECT * FROM crosstab_out('SELECT rowid, attribute, val FROM ct where rowclass = ''group1'' ORDER BY 1,2;');
- rowid | att1 | att2 | att3 
--------+------+------+------
- test1 | val1 | val2 | val3
- test2 | val5 | val6 | val7
-(2 rows)
+ rowid | att1 | att2  | att3  
+-------+------+-------+-------
+ test1 | val1 | val2  | val3
+ test2 | val5 | val6  | val7
+       | val9 | val10 | val11
+(3 rows)
 
 --
 -- hash based crosstab
@@ -150,38 +160,46 @@ insert into cth values(DEFAULT,'test2','02 March 2003','temperature','53');
 insert into cth values(DEFAULT,'test2','02 March 2003','test_result','FAIL');
 insert into cth values(DEFAULT,'test2','02 March 2003','test_startdate','01 March 2003');
 insert into cth values(DEFAULT,'test2','02 March 2003','volts','3.1234');
+-- next group tests for NULL rowids
+insert into cth values(DEFAULT,NULL,'25 October 2007','temperature','57');
+insert into cth values(DEFAULT,NULL,'25 October 2007','test_result','PASS');
+insert into cth values(DEFAULT,NULL,'25 October 2007','test_startdate','24 October 2007');
+insert into cth values(DEFAULT,NULL,'25 October 2007','volts','1.41234');
 -- return attributes as plain text
 SELECT * FROM crosstab(
   'SELECT rowid, rowdt, attribute, val FROM cth ORDER BY 1',
   'SELECT DISTINCT attribute FROM cth ORDER BY 1')
 AS c(rowid text, rowdt timestamp, temperature text, test_result text, test_startdate text, volts text);
- rowid |          rowdt           | temperature | test_result | test_startdate | volts  
--------+--------------------------+-------------+-------------+----------------+--------
- test1 | Sat Mar 01 00:00:00 2003 | 42          | PASS        |                | 2.6987
- test2 | Sun Mar 02 00:00:00 2003 | 53          | FAIL        | 01 March 2003  | 3.1234
-(2 rows)
+ rowid |          rowdt           | temperature | test_result | test_startdate  |  volts  
+-------+--------------------------+-------------+-------------+-----------------+---------
+ test1 | Sat Mar 01 00:00:00 2003 | 42          | PASS        |                 | 2.6987
+ test2 | Sun Mar 02 00:00:00 2003 | 53          | FAIL        | 01 March 2003   | 3.1234
+       | Thu Oct 25 00:00:00 2007 | 57          | PASS        | 24 October 2007 | 1.41234
+(3 rows)
 
 -- this time without rowdt
 SELECT * FROM crosstab(
   'SELECT rowid, attribute, val FROM cth ORDER BY 1',
   'SELECT DISTINCT attribute FROM cth ORDER BY 1')
 AS c(rowid text, temperature text, test_result text, test_startdate text, volts text);
- rowid | temperature | test_result | test_startdate | volts  
--------+-------------+-------------+----------------+--------
- test1 | 42          | PASS        |                | 2.6987
- test2 | 53          | FAIL        | 01 March 2003  | 3.1234
-(2 rows)
+ rowid | temperature | test_result | test_startdate  |  volts  
+-------+-------------+-------------+-----------------+---------
+ test1 | 42          | PASS        |                 | 2.6987
+ test2 | 53          | FAIL        | 01 March 2003   | 3.1234
+       | 57          | PASS        | 24 October 2007 | 1.41234
+(3 rows)
 
 -- convert attributes to specific datatypes
 SELECT * FROM crosstab(
   'SELECT rowid, rowdt, attribute, val FROM cth ORDER BY 1',
   'SELECT DISTINCT attribute FROM cth ORDER BY 1')
 AS c(rowid text, rowdt timestamp, temperature int4, test_result text, test_startdate timestamp, volts float8);
- rowid |          rowdt           | temperature | test_result |      test_startdate      | volts  
--------+--------------------------+-------------+-------------+--------------------------+--------
- test1 | Sat Mar 01 00:00:00 2003 |          42 | PASS        |                          | 2.6987
- test2 | Sun Mar 02 00:00:00 2003 |          53 | FAIL        | Sat Mar 01 00:00:00 2003 | 3.1234
-(2 rows)
+ rowid |          rowdt           | temperature | test_result |      test_startdate      |  volts  
+-------+--------------------------+-------------+-------------+--------------------------+---------
+ test1 | Sat Mar 01 00:00:00 2003 |          42 | PASS        |                          |  2.6987
+ test2 | Sun Mar 02 00:00:00 2003 |          53 | FAIL        | Sat Mar 01 00:00:00 2003 |  3.1234
+       | Thu Oct 25 00:00:00 2007 |          57 | PASS        | Wed Oct 24 00:00:00 2007 | 1.41234
+(3 rows)
 
 -- source query and category query out of sync
 SELECT * FROM crosstab(
@@ -192,7 +210,8 @@ AS c(rowid text, rowdt timestamp, temperature int4, test_result text, test_start
 -------+--------------------------+-------------+-------------+--------------------------
  test1 | Sat Mar 01 00:00:00 2003 |          42 | PASS        | 
  test2 | Sun Mar 02 00:00:00 2003 |          53 | FAIL        | Sat Mar 01 00:00:00 2003
-(2 rows)
+       | Thu Oct 25 00:00:00 2007 |          57 | PASS        | Wed Oct 24 00:00:00 2007
+(3 rows)
 
 -- if category query generates no rows, get expected error
 SELECT * FROM crosstab(
@@ -235,11 +254,12 @@ LANGUAGE C STABLE STRICT;
 SELECT * FROM crosstab_named(
   'SELECT rowid, rowdt, attribute, val FROM cth ORDER BY 1',
   'SELECT DISTINCT attribute FROM cth ORDER BY 1');
- rowid |          rowdt           | temperature | test_result |      test_startdate      | volts  
--------+--------------------------+-------------+-------------+--------------------------+--------
- test1 | Sat Mar 01 00:00:00 2003 |          42 | PASS        |                          | 2.6987
- test2 | Sun Mar 02 00:00:00 2003 |          53 | FAIL        | Sat Mar 01 00:00:00 2003 | 3.1234
-(2 rows)
+ rowid |          rowdt           | temperature | test_result |      test_startdate      |  volts  
+-------+--------------------------+-------------+-------------+--------------------------+---------
+ test1 | Sat Mar 01 00:00:00 2003 |          42 | PASS        |                          |  2.6987
+ test2 | Sun Mar 02 00:00:00 2003 |          53 | FAIL        | Sat Mar 01 00:00:00 2003 |  3.1234
+       | Thu Oct 25 00:00:00 2007 |          57 | PASS        | Wed Oct 24 00:00:00 2007 | 1.41234
+(3 rows)
 
 -- check it works with OUT parameters
 CREATE FUNCTION crosstab_out(text, text,
@@ -252,11 +272,12 @@ LANGUAGE C STABLE STRICT;
 SELECT * FROM crosstab_out(
   'SELECT rowid, rowdt, attribute, val FROM cth ORDER BY 1',
   'SELECT DISTINCT attribute FROM cth ORDER BY 1');
- rowid |          rowdt           | temperature | test_result |      test_startdate      | volts  
--------+--------------------------+-------------+-------------+--------------------------+--------
- test1 | Sat Mar 01 00:00:00 2003 |          42 | PASS        |                          | 2.6987
- test2 | Sun Mar 02 00:00:00 2003 |          53 | FAIL        | Sat Mar 01 00:00:00 2003 | 3.1234
-(2 rows)
+ rowid |          rowdt           | temperature | test_result |      test_startdate      |  volts  
+-------+--------------------------+-------------+-------------+--------------------------+---------
+ test1 | Sat Mar 01 00:00:00 2003 |          42 | PASS        |                          |  2.6987
+ test2 | Sun Mar 02 00:00:00 2003 |          53 | FAIL        | Sat Mar 01 00:00:00 2003 |  3.1234
+       | Thu Oct 25 00:00:00 2007 |          57 | PASS        | Wed Oct 24 00:00:00 2007 | 1.41234
+(3 rows)
 
 --
 -- connectby

contrib/tablefunc/sql/tablefunc.sql

@@ -61,6 +61,11 @@ insert into cth values(DEFAULT,'test2','02 March 2003','temperature','53');
 insert into cth values(DEFAULT,'test2','02 March 2003','test_result','FAIL');
 insert into cth values(DEFAULT,'test2','02 March 2003','test_startdate','01 March 2003');
 insert into cth values(DEFAULT,'test2','02 March 2003','volts','3.1234');
+-- next group tests for NULL rowids
+insert into cth values(DEFAULT,NULL,'25 October 2007','temperature','57');
+insert into cth values(DEFAULT,NULL,'25 October 2007','test_result','PASS');
+insert into cth values(DEFAULT,NULL,'25 October 2007','test_startdate','24 October 2007');
+insert into cth values(DEFAULT,NULL,'25 October 2007','volts','1.41234');
 
 -- return attributes as plain text
 SELECT * FROM crosstab(

contrib/tablefunc/tablefunc.c

@@ -106,6 +106,18 @@ typedef struct
 		} \
 	} while (0)
 
+#define xpstrdup(tgtvar_, srcvar_) \
+	do { \
+		if (srcvar_) \
+			tgtvar_ = pstrdup(srcvar_); \
+		else \
+			tgtvar_ = NULL; \
+	} while (0)
+
+#define xstreq(tgtvar_, srcvar_) \
+	(((tgtvar_ == NULL) && (srcvar_ == NULL)) || \
+	 ((tgtvar_ != NULL) && (srcvar_ != NULL) && (strcmp(tgtvar_, srcvar_) == 0)))
+
 /* sign, 10 digits, '\0' */
 #define INT32_STRLEN	12
 
@@ -355,6 +367,7 @@ crosstab(PG_FUNCTION_ARGS)
 	crosstab_fctx *fctx;
 	int			i;
 	int			num_categories;
+	bool		firstpass = false;
 	MemoryContext oldcontext;
 
 	/* stuff done only on the first call of the function */
@@ -469,6 +482,7 @@ crosstab(PG_FUNCTION_ARGS)
 		funcctx->max_calls = proc;
 
 		MemoryContextSwitchTo(oldcontext);
+		firstpass = true;
 	}
 
 	/* stuff done on every call of the function */
@@ -500,7 +514,7 @@ crosstab(PG_FUNCTION_ARGS)
 		HeapTuple	tuple;
 		Datum		result;
 		char	  **values;
-		bool		allnulls = true;
+		bool		skip_tuple = false;
 
 		while (true)
 		{
@@ -530,26 +544,35 @@ crosstab(PG_FUNCTION_ARGS)
 				rowid = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
 
 				/*
-				 * If this is the first pass through the values for this rowid
-				 * set it, otherwise make sure it hasn't changed on us. Also
-				 * check to see if the rowid is the same as that of the last
-				 * tuple sent -- if so, skip this tuple entirely
+				 * If this is the first pass through the values for this
+				 * rowid, set the first column to rowid
 				 */
 				if (i == 0)
-					values[0] = pstrdup(rowid);
-
-				if ((rowid != NULL) && (strcmp(rowid, values[0]) == 0))
 				{
-					if ((lastrowid != NULL) && (strcmp(rowid, lastrowid) == 0))
+					xpstrdup(values[0], rowid);
+
+					/*
+					 * Check to see if the rowid is the same as that of the last
+					 * tuple sent -- if so, skip this tuple entirely
+					 */
+					if (!firstpass && xstreq(lastrowid, rowid))
+					{
+						skip_tuple = true;
 						break;
-					else if (allnulls == true)
-						allnulls = false;
+					}
+				}
 
+				/*
+				 * If rowid hasn't changed on us, continue building the
+				 * ouput tuple.
+				 */
+				if (xstreq(rowid, values[0]))
+				{
 					/*
-					 * Get the next category item value, which is alway
+					 * Get the next category item value, which is always
 					 * attribute number three.
 					 *
-					 * Be careful to sssign the value to the array index based
+					 * Be careful to assign the value to the array index based
 					 * on which category we are presently processing.
 					 */
 					values[1 + i] = SPI_getvalue(spi_tuple, spi_tupdesc, 3);
@@ -572,26 +595,22 @@ crosstab(PG_FUNCTION_ARGS)
 					call_cntr = --funcctx->call_cntr;
 					break;
 				}
-
-				if (rowid != NULL)
-					xpfree(rowid);
+				xpfree(rowid);
 			}
 
-			xpfree(fctx->lastrowid);
+			/*
+			 * switch to memory context appropriate for multiple function
+			 * calls
+			 */
+			oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
-			if (values[0] != NULL)
-			{
-				/*
-				 * switch to memory context appropriate for multiple function
-				 * calls
-				 */
-				oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+			xpfree(fctx->lastrowid);
+			xpstrdup(fctx->lastrowid, values[0]);
+			lastrowid = fctx->lastrowid;
 
-				lastrowid = fctx->lastrowid = pstrdup(values[0]);
-				MemoryContextSwitchTo(oldcontext);
-			}
+			MemoryContextSwitchTo(oldcontext);
 
-			if (!allnulls)
+			if (!skip_tuple)
 			{
 				/* build the tuple */
 				tuple = BuildTupleFromCStrings(attinmeta, values);
@@ -625,6 +644,9 @@ crosstab(PG_FUNCTION_ARGS)
 					SPI_finish();
 					SRF_RETURN_DONE(funcctx);
 				}
+
+				/* need to reset this before the next tuple is started */
+				skip_tuple = false;
 			}
 		}
 	}
@@ -856,6 +878,7 @@ get_crosstab_tuplestore(char *sql,
 		int			ncols = spi_tupdesc->natts;
 		char	   *rowid;
 		char	   *lastrowid = NULL;
+		bool		firstpass = true;
 		int			i,
 					j;
 		int			result_ncols;
@@ -918,21 +941,17 @@ get_crosstab_tuplestore(char *sql,
 			/* get the rowid from the current sql result tuple */
 			rowid = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
 
-			/* if rowid is null, skip this tuple entirely */
-			if (rowid == NULL)
-				continue;
-
 			/*
 			 * if we're on a new output row, grab the column values up to
 			 * column N-2 now
 			 */
-			if ((lastrowid == NULL) || (strcmp(rowid, lastrowid) != 0))
+			if (firstpass || !xstreq(lastrowid, rowid))
 			{
 				/*
 				 * a new row means we need to flush the old one first, unless
 				 * we're on the very first row
 				 */
-				if (lastrowid != NULL)
+				if (!firstpass)
 				{
 					/* rowid changed, flush the previous output row */
 					tuple = BuildTupleFromCStrings(attinmeta, values);
@@ -949,6 +968,9 @@ get_crosstab_tuplestore(char *sql,
 				values[0] = rowid;
 				for (j = 1; j < ncols - 2; j++)
 					values[j] = SPI_getvalue(spi_tuple, spi_tupdesc, j + 1);
+
+				/* we're no longer on the first pass */
+				firstpass = false;
 			}
 
 			/* look up the category and fill in the appropriate column */
@@ -964,7 +986,7 @@ get_crosstab_tuplestore(char *sql,
 			}
 
 			xpfree(lastrowid);
-			lastrowid = pstrdup(rowid);
+			xpstrdup(lastrowid, rowid);
 		}
 
 		/* flush the last output row */