Change AdjustIntervalForTypmod to not discard higher-order field values on the

grounds that they don't fit into the specified interval qualifier (typmod).
This behavior, while of long standing, is clearly wrong per spec --- for
example the value INTERVAL '999' SECOND means 999 seconds and should not be
reduced to less than 60 seconds.

In some cases there could be grounds to raise an error if higher-order field
values are not given as zero; for example '1 year 1 month'::INTERVAL MONTH
should arguably be taken as an error rather than equivalent to 13 months.
However our internal representation doesn't allow us to do that in a fashion
that would consistently reject all and only the cases that a strict reading
of the spec would suggest.  Also, seeing that for example INTERVAL '13' MONTH
will print out as '1 year 1 mon', we have to be careful not to create a
situation where valid data will fail to dump and reload.  The present patch
therefore takes the attitude of not throwing an error in any such case.
We might want to revisit that in future but it would take more redesign
than seems prudent in late beta.

Per a complaint from Sebastien Flaesch and subsequent discussion.  While
at other times we might have just postponed such an issue to the next
development cycle, 8.4 already has changed the parsing of interval literals
quite a bit in an effort to accept all spec-compliant cases correctly.
This seems like a change that should be part of that rather than coming
along later.

src/backend/utils/adt/timestamp.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.199 2009/05/26 02:17:50 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.200 2009/06/01 23:55:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -955,13 +955,32 @@ AdjustIntervalForTypmod(Interval *interval, int32 typmod)
 
 	/*
 	 * Unspecified range and precision? Then not necessary to adjust. Setting
-	 * typmod to -1 is the convention for all types.
+	 * typmod to -1 is the convention for all data types.
 	 */
 	if (typmod >= 0)
 	{
 		int			range = INTERVAL_RANGE(typmod);
 		int			precision = INTERVAL_PRECISION(typmod);
 
+		/*
+		 * Our interpretation of intervals with a limited set of fields
+		 * is that fields to the right of the last one specified are zeroed
+		 * out, but those to the left of it remain valid.  Thus for example
+		 * there is no operational difference between INTERVAL YEAR TO MONTH
+		 * and INTERVAL MONTH.  In some cases we could meaningfully enforce
+		 * that higher-order fields are zero; for example INTERVAL DAY could
+		 * reject nonzero "month" field.  However that seems a bit pointless
+		 * when we can't do it consistently.  (We cannot enforce a range limit
+		 * on the highest expected field, since we do not have any equivalent
+		 * of SQL's <interval leading field precision>.)
+		 *
+		 * Note: before PG 8.4 we interpreted a limited set of fields as
+		 * actually causing a "modulo" operation on a given value, potentially
+		 * losing high-order as well as low-order information.  But there is
+		 * no support for such behavior in the standard, and it seems fairly
+		 * undesirable on data consistency grounds anyway.  Now we only
+		 * perform truncation or rounding of low-order fields.
+		 */
 		if (range == INTERVAL_FULL_RANGE)
 		{
 			/* Do nothing... */
@@ -974,27 +993,21 @@ AdjustIntervalForTypmod(Interval *interval, int32 typmod)
 		}
 		else if (range == INTERVAL_MASK(MONTH))
 		{
-			interval->month %= MONTHS_PER_YEAR;
 			interval->day = 0;
 			interval->time = 0;
 		}
 		/* YEAR TO MONTH */
 		else if (range == (INTERVAL_MASK(YEAR) | INTERVAL_MASK(MONTH)))
 		{
-			/* month is already year to month */
 			interval->day = 0;
 			interval->time = 0;
 		}
 		else if (range == INTERVAL_MASK(DAY))
 		{
-			interval->month = 0;
 			interval->time = 0;
 		}
 		else if (range == INTERVAL_MASK(HOUR))
 		{
-			interval->month = 0;
-			interval->day = 0;
-
 #ifdef HAVE_INT64_TIMESTAMP
 			interval->time = (interval->time / USECS_PER_HOUR) *
 				USECS_PER_HOUR;
@@ -1004,42 +1017,21 @@ AdjustIntervalForTypmod(Interval *interval, int32 typmod)
 		}
 		else if (range == INTERVAL_MASK(MINUTE))
 		{
-			TimeOffset	hour;
-
-			interval->month = 0;
-			interval->day = 0;
-
 #ifdef HAVE_INT64_TIMESTAMP
-			hour = interval->time / USECS_PER_HOUR;
-			interval->time -= hour * USECS_PER_HOUR;
 			interval->time = (interval->time / USECS_PER_MINUTE) *
 				USECS_PER_MINUTE;
 #else
-			TMODULO(interval->time, hour, (double) SECS_PER_HOUR);
 			interval->time = ((int) (interval->time / SECS_PER_MINUTE)) * (double) SECS_PER_MINUTE;
 #endif
 		}
 		else if (range == INTERVAL_MASK(SECOND))
 		{
-			TimeOffset	minute;
-
-			interval->month = 0;
-			interval->day = 0;
-
-#ifdef HAVE_INT64_TIMESTAMP
-			minute = interval->time / USECS_PER_MINUTE;
-			interval->time -= minute * USECS_PER_MINUTE;
-#else
-			TMODULO(interval->time, minute, (double) SECS_PER_MINUTE);
-			/* return subseconds too */
-#endif
+			/* fractional-second rounding will be dealt with below */
 		}
 		/* DAY TO HOUR */
 		else if (range == (INTERVAL_MASK(DAY) |
 						   INTERVAL_MASK(HOUR)))
 		{
-			interval->month = 0;
-
 #ifdef HAVE_INT64_TIMESTAMP
 			interval->time = (interval->time / USECS_PER_HOUR) *
 				USECS_PER_HOUR;
@@ -1052,8 +1044,6 @@ AdjustIntervalForTypmod(Interval *interval, int32 typmod)
 						   INTERVAL_MASK(HOUR) |
 						   INTERVAL_MASK(MINUTE)))
 		{
-			interval->month = 0;
-
 #ifdef HAVE_INT64_TIMESTAMP
 			interval->time = (interval->time / USECS_PER_MINUTE) *
 				USECS_PER_MINUTE;
@@ -1066,15 +1056,13 @@ AdjustIntervalForTypmod(Interval *interval, int32 typmod)
 						   INTERVAL_MASK(HOUR) |
 						   INTERVAL_MASK(MINUTE) |
 						   INTERVAL_MASK(SECOND)))
-			interval->month = 0;
-
+		{
+			/* fractional-second rounding will be dealt with below */
+		}
 		/* HOUR TO MINUTE */
 		else if (range == (INTERVAL_MASK(HOUR) |
 						   INTERVAL_MASK(MINUTE)))
 		{
-			interval->month = 0;
-			interval->day = 0;
-
 #ifdef HAVE_INT64_TIMESTAMP
 			interval->time = (interval->time / USECS_PER_MINUTE) *
 				USECS_PER_MINUTE;
@@ -1087,25 +1075,13 @@ AdjustIntervalForTypmod(Interval *interval, int32 typmod)
 						   INTERVAL_MASK(MINUTE) |
 						   INTERVAL_MASK(SECOND)))
 		{
-			interval->month = 0;
-			interval->day = 0;
-			/* return subseconds too */
+			/* fractional-second rounding will be dealt with below */
 		}
 		/* MINUTE TO SECOND */
 		else if (range == (INTERVAL_MASK(MINUTE) |
 						   INTERVAL_MASK(SECOND)))
 		{
-			TimeOffset	hour;
-
-			interval->month = 0;
-			interval->day = 0;
-
-#ifdef HAVE_INT64_TIMESTAMP
-			hour = interval->time / USECS_PER_HOUR;
-			interval->time -= hour * USECS_PER_HOUR;
-#else
-			TMODULO(interval->time, hour, (double) SECS_PER_HOUR);
-#endif
+			/* fractional-second rounding will be dealt with below */
 		}
 		else
 			elog(ERROR, "unrecognized interval typmod: %d", typmod);
@@ -1148,8 +1124,6 @@ AdjustIntervalForTypmod(Interval *interval, int32 typmod)
 #endif
 		}
 	}
-
-	return;
 }
 
 

src/test/regress/expected/interval.out

@@ -358,12 +358,46 @@ SELECT '1:20:05 5 microseconds'::interval;          -- error
 ERROR:  invalid input syntax for type interval: "1:20:05 5 microseconds"
 LINE 1: SELECT '1:20:05 5 microseconds'::interval;
                ^
+SELECT '1 day 1 day'::interval;                     -- error
+ERROR:  invalid input syntax for type interval: "1 day 1 day"
+LINE 1: SELECT '1 day 1 day'::interval;
+               ^
 SELECT interval '1-2';  -- SQL year-month literal
    interval    
 ---------------
  1 year 2 mons
 (1 row)
 
+SELECT interval '999' second;  -- oversize leading field is ok
+ interval 
+----------
+ 00:16:39
+(1 row)
+
+SELECT interval '999' minute;
+ interval 
+----------
+ 16:39:00
+(1 row)
+
+SELECT interval '999' hour;
+ interval  
+-----------
+ 999:00:00
+(1 row)
+
+SELECT interval '999' day;
+ interval 
+----------
+ 999 days
+(1 row)
+
+SELECT interval '999' month;
+    interval     
+-----------------
+ 83 years 3 mons
+(1 row)
+
 -- test SQL-spec syntaxes for restricted field sets
 SELECT interval '1' year;
  interval 
@@ -472,15 +506,15 @@ ERROR:  invalid input syntax for type interval: "1 2"
 LINE 1: SELECT interval '1 2' hour to minute;
                         ^
 SELECT interval '1 2:03' hour to minute;
- interval 
-----------
- 02:03:00
+    interval    
+----------------
+ 1 day 02:03:00
 (1 row)
 
 SELECT interval '1 2:03:04' hour to minute;
- interval 
-----------
- 02:03:00
+    interval    
+----------------
+ 1 day 02:03:00
 (1 row)
 
 SELECT interval '1 2' hour to second;
@@ -488,15 +522,15 @@ ERROR:  invalid input syntax for type interval: "1 2"
 LINE 1: SELECT interval '1 2' hour to second;
                         ^
 SELECT interval '1 2:03' hour to second;
- interval 
-----------
- 02:03:00
+    interval    
+----------------
+ 1 day 02:03:00
 (1 row)
 
 SELECT interval '1 2:03:04' hour to second;
- interval 
-----------
- 02:03:04
+    interval    
+----------------
+ 1 day 02:03:04
 (1 row)
 
 SELECT interval '1 2' minute to second;
@@ -504,17 +538,31 @@ ERROR:  invalid input syntax for type interval: "1 2"
 LINE 1: SELECT interval '1 2' minute to second;
                         ^
 SELECT interval '1 2:03' minute to second;
- interval 
-----------
- 00:02:03
+    interval    
+----------------
+ 1 day 00:02:03
 (1 row)
 
 SELECT interval '1 2:03:04' minute to second;
- interval 
-----------
- 00:03:04
+    interval    
+----------------
+ 1 day 02:03:04
 (1 row)
 
+SELECT interval '123 11' day to hour; -- ok
+     interval      
+-------------------
+ 123 days 11:00:00
+(1 row)
+
+SELECT interval '123 11' day; -- not ok
+ERROR:  invalid input syntax for type interval: "123 11"
+LINE 1: SELECT interval '123 11' day;
+                        ^
+SELECT interval '123 11'; -- not ok, too ambiguous
+ERROR:  invalid input syntax for type interval: "123 11"
+LINE 1: SELECT interval '123 11';
+                        ^
 -- test syntaxes for restricted precision
 SELECT interval(0) '1 day 01:23:45.6789';
     interval    
@@ -585,15 +633,15 @@ ERROR:  invalid input syntax for type interval: "1 2.345"
 LINE 1: SELECT interval '1 2.345' hour to second(2);
                         ^
 SELECT interval '1 2:03.45678' hour to second(2);
-  interval   
--------------
- 00:02:03.46
+     interval      
+-------------------
+ 1 day 00:02:03.46
 (1 row)
 
 SELECT interval '1 2:03:04.5678' hour to second(2);
-  interval   
--------------
- 02:03:04.57
+     interval      
+-------------------
+ 1 day 02:03:04.57
 (1 row)
 
 SELECT interval '1 2.3456' minute to second(2);
@@ -601,15 +649,15 @@ ERROR:  invalid input syntax for type interval: "1 2.3456"
 LINE 1: SELECT interval '1 2.3456' minute to second(2);
                         ^
 SELECT interval '1 2:03.5678' minute to second(2);
-  interval   
--------------
- 00:02:03.57
+     interval      
+-------------------
+ 1 day 00:02:03.57
 (1 row)
 
 SELECT interval '1 2:03:04.5678' minute to second(2);
-  interval   
--------------
- 00:03:04.57
+     interval      
+-------------------
+ 1 day 02:03:04.57
 (1 row)
 
 -- test inputting and outputting SQL standard interval literals

src/test/regress/sql/interval.sql

@@ -130,7 +130,13 @@ SELECT '1 second 2 seconds'::interval;              -- error
 SELECT '10 milliseconds 20 milliseconds'::interval; -- error
 SELECT '5.5 seconds 3 milliseconds'::interval;      -- error
 SELECT '1:20:05 5 microseconds'::interval;          -- error
+SELECT '1 day 1 day'::interval;                     -- error
 SELECT interval '1-2';  -- SQL year-month literal
+SELECT interval '999' second;  -- oversize leading field is ok
+SELECT interval '999' minute;
+SELECT interval '999' hour;
+SELECT interval '999' day;
+SELECT interval '999' month;
 
 -- test SQL-spec syntaxes for restricted field sets
 SELECT interval '1' year;
@@ -159,6 +165,9 @@ SELECT interval '1 2:03:04' hour to second;
 SELECT interval '1 2' minute to second;
 SELECT interval '1 2:03' minute to second;
 SELECT interval '1 2:03:04' minute to second;
+SELECT interval '123 11' day to hour; -- ok
+SELECT interval '123 11' day; -- not ok
+SELECT interval '123 11'; -- not ok, too ambiguous
 
 -- test syntaxes for restricted precision
 SELECT interval(0) '1 day 01:23:45.6789';