Adjust timestamp regression tests to prevent two low-probability failure

cases.  Recent buildfarm experience shows that it is sometimes possible
to execute several SQL commands in less time than the granularity of
Windows' not-very-high-resolution gettimeofday(), leading to a failure
because the tests expect the value of now() to change and it doesn't.
Also, it was recognized some time ago that the same area of the tests
could fail if local midnight passes between the insertion and the checking
of the values for 'yesterday', 'tomorrow', etc.  Clean all this up per
ideas from myself and Greg Stark.

There remains a window for failure if the transaction block is entered
exactly at local midnight (so that 'now' and 'today' have the same value),
but that seems low-probability enough to live with.

Since the point of this change is mostly to eliminate buildfarm noise,
back-patch to all versions we are still actively testing.

4 files changed, 74 insertions, 39 deletions

diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out
index d6f14ff6ef3..773281f4a58 100644
--- a/src/test/regress/expected/timestamp.out
+++ b/src/test/regress/expected/timestamp.out
@@ -3,18 +3,20 @@
 --
 -- needed so tests pass even in Australia
 SET australian_timezones = 'off';
-CREATE TABLE TIMESTAMP_TBL ( d1 timestamp(2) without time zone);
--- Shorthand values
--- Not directly usable for regression testing since these are not constants.
--- So, just try to test parser and hope for the best - thomas 97/04/26
--- NB: could get a failure if local midnight passes during the next few
--- statements.
+CREATE TABLE TIMESTAMP_TBL (d1 timestamp(2) without time zone);
+-- Test shorthand input values
+-- We can't just "select" the results since they aren't constants; test for
+-- equality instead.  We can do that by running the test inside a transaction
+-- block, within which the value of 'now' shouldn't change.
+-- NOTE: it is possible for this part of the test to fail if the transaction
+-- block is entered exactly at local midnight; then 'now' and 'today' have
+-- the same values and the counts will come out different.
+BEGIN;
 INSERT INTO TIMESTAMP_TBL VALUES ('now');
-INSERT INTO TIMESTAMP_TBL VALUES ('current');
-ERROR:  date/time value "current" is no longer supported
 INSERT INTO TIMESTAMP_TBL VALUES ('today');
 INSERT INTO TIMESTAMP_TBL VALUES ('yesterday');
 INSERT INTO TIMESTAMP_TBL VALUES ('tomorrow');
+-- time zone should be ignored by this data type
 INSERT INTO TIMESTAMP_TBL VALUES ('tomorrow EST');
 INSERT INTO TIMESTAMP_TBL VALUES ('tomorrow zulu');
 SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'today';
@@ -23,10 +25,10 @@ SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone
    1
 (1 row)
 
-SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'tomorrow';
- one 
------
-   3
+SELECT count(*) AS Three FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'tomorrow';
+ three 
+-------
+     3
 (1 row)
 
 SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'yesterday';
@@ -35,12 +37,13 @@ SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone
    1
 (1 row)
 
-SELECT count(*) AS None FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'now';
- none 
-------
-    0
+SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp(2) without time zone 'now';
+ one 
+-----
+   1
 (1 row)
 
+COMMIT;
 DELETE FROM TIMESTAMP_TBL;
 -- verify uniform transaction time within transaction block
 BEGIN;
@@ -52,7 +55,7 @@ SELECT count(*) AS two FROM TIMESTAMP_TBL WHERE d1 = timestamp(2) without time z
    2
 (1 row)
 
-END;
+COMMIT;
 DELETE FROM TIMESTAMP_TBL;
 -- Special values
 INSERT INTO TIMESTAMP_TBL VALUES ('-infinity');
@@ -61,6 +64,8 @@ INSERT INTO TIMESTAMP_TBL VALUES ('epoch');
 -- Obsolete special values
 INSERT INTO TIMESTAMP_TBL VALUES ('invalid');
 ERROR:  date/time value "invalid" is no longer supported
+INSERT INTO TIMESTAMP_TBL VALUES ('current');
+ERROR:  date/time value "current" is no longer supported
 -- Postgres v6.0 standard output format
 INSERT INTO TIMESTAMP_TBL VALUES ('Mon Feb 10 17:32:01 1997 PST');
 INSERT INTO TIMESTAMP_TBL VALUES ('Invalid Abstime');
diff --git a/src/test/regress/expected/timestamptz.out b/src/test/regress/expected/timestamptz.out
index 20560b6bc87..3a0bf9b7388 100644
--- a/src/test/regress/expected/timestamptz.out
+++ b/src/test/regress/expected/timestamptz.out
@@ -3,10 +3,16 @@
 --
 -- needed so tests pass even in Australia
 SET australian_timezones = 'off';
-CREATE TABLE TIMESTAMPTZ_TBL ( d1 timestamp(2) with time zone);
+CREATE TABLE TIMESTAMPTZ_TBL (d1 timestamp(2) with time zone);
+-- Test shorthand input values
+-- We can't just "select" the results since they aren't constants; test for
+-- equality instead.  We can do that by running the test inside a transaction
+-- block, within which the value of 'now' shouldn't change.
+-- NOTE: it is possible for this part of the test to fail if the transaction
+-- block is entered exactly at local midnight; then 'now' and 'today' have
+-- the same values and the counts will come out different.
+BEGIN;
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('now');
-INSERT INTO TIMESTAMPTZ_TBL VALUES ('current');
-ERROR:  date/time value "current" is no longer supported
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('today');
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('yesterday');
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('tomorrow');
@@ -30,12 +36,13 @@ SELECT count(*) AS One FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp with time zone
    1
 (1 row)
 
-SELECT count(*) AS None FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp with time zone 'now';
- none 
-------
-    0
+SELECT count(*) AS One FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp(2) with time zone 'now';
+ one 
+-----
+   1
 (1 row)
 
+COMMIT;
 DELETE FROM TIMESTAMPTZ_TBL;
 -- verify uniform transaction time within transaction block
 BEGIN;
@@ -47,7 +54,7 @@ SELECT count(*) AS two FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp(2) with time zo
    2
 (1 row)
 
-END;
+COMMIT;
 DELETE FROM TIMESTAMPTZ_TBL;
 -- Special values
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('-infinity');
@@ -56,6 +63,8 @@ INSERT INTO TIMESTAMPTZ_TBL VALUES ('epoch');
 -- Obsolete special values
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('invalid');
 ERROR:  date/time value "invalid" is no longer supported
+INSERT INTO TIMESTAMPTZ_TBL VALUES ('current');
+ERROR:  date/time value "current" is no longer supported
 -- Postgres v6.0 standard output format
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('Mon Feb 10 17:32:01 1997 PST');
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('Invalid Abstime');
diff --git a/src/test/regress/sql/timestamp.sql b/src/test/regress/sql/timestamp.sql
index ceda76f546a..6d6640bd26d 100644
--- a/src/test/regress/sql/timestamp.sql
+++ b/src/test/regress/sql/timestamp.sql
@@ -4,26 +4,32 @@
 -- needed so tests pass even in Australia
 SET australian_timezones = 'off';
 
-CREATE TABLE TIMESTAMP_TBL ( d1 timestamp(2) without time zone);
+CREATE TABLE TIMESTAMP_TBL (d1 timestamp(2) without time zone);
 
--- Shorthand values
--- Not directly usable for regression testing since these are not constants.
--- So, just try to test parser and hope for the best - thomas 97/04/26
--- NB: could get a failure if local midnight passes during the next few
--- statements.
+-- Test shorthand input values
+-- We can't just "select" the results since they aren't constants; test for
+-- equality instead.  We can do that by running the test inside a transaction
+-- block, within which the value of 'now' shouldn't change.
+-- NOTE: it is possible for this part of the test to fail if the transaction
+-- block is entered exactly at local midnight; then 'now' and 'today' have
+-- the same values and the counts will come out different.
+
+BEGIN;
 
 INSERT INTO TIMESTAMP_TBL VALUES ('now');
-INSERT INTO TIMESTAMP_TBL VALUES ('current');
 INSERT INTO TIMESTAMP_TBL VALUES ('today');
 INSERT INTO TIMESTAMP_TBL VALUES ('yesterday');
 INSERT INTO TIMESTAMP_TBL VALUES ('tomorrow');
+-- time zone should be ignored by this data type
 INSERT INTO TIMESTAMP_TBL VALUES ('tomorrow EST');
 INSERT INTO TIMESTAMP_TBL VALUES ('tomorrow zulu');
 
 SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'today';
-SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'tomorrow';
+SELECT count(*) AS Three FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'tomorrow';
 SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'yesterday';
-SELECT count(*) AS None FROM TIMESTAMP_TBL WHERE d1 = timestamp without time zone 'now';
+SELECT count(*) AS One FROM TIMESTAMP_TBL WHERE d1 = timestamp(2) without time zone 'now';
+
+COMMIT;
 
 DELETE FROM TIMESTAMP_TBL;
 
@@ -32,7 +38,8 @@ BEGIN;
 INSERT INTO TIMESTAMP_TBL VALUES ('now');
 INSERT INTO TIMESTAMP_TBL VALUES ('now');
 SELECT count(*) AS two FROM TIMESTAMP_TBL WHERE d1 = timestamp(2) without time zone 'now';
-END;
+COMMIT;
+
 DELETE FROM TIMESTAMP_TBL;
 
 -- Special values
@@ -41,6 +48,7 @@ INSERT INTO TIMESTAMP_TBL VALUES ('infinity');
 INSERT INTO TIMESTAMP_TBL VALUES ('epoch');
 -- Obsolete special values
 INSERT INTO TIMESTAMP_TBL VALUES ('invalid');
+INSERT INTO TIMESTAMP_TBL VALUES ('current');
 
 -- Postgres v6.0 standard output format
 INSERT INTO TIMESTAMP_TBL VALUES ('Mon Feb 10 17:32:01 1997 PST');
diff --git a/src/test/regress/sql/timestamptz.sql b/src/test/regress/sql/timestamptz.sql
index 12572fa7ce4..81528d5d583 100644
--- a/src/test/regress/sql/timestamptz.sql
+++ b/src/test/regress/sql/timestamptz.sql
@@ -4,10 +4,19 @@
 -- needed so tests pass even in Australia
 SET australian_timezones = 'off';
 
-CREATE TABLE TIMESTAMPTZ_TBL ( d1 timestamp(2) with time zone);
+CREATE TABLE TIMESTAMPTZ_TBL (d1 timestamp(2) with time zone);
+
+-- Test shorthand input values
+-- We can't just "select" the results since they aren't constants; test for
+-- equality instead.  We can do that by running the test inside a transaction
+-- block, within which the value of 'now' shouldn't change.
+-- NOTE: it is possible for this part of the test to fail if the transaction
+-- block is entered exactly at local midnight; then 'now' and 'today' have
+-- the same values and the counts will come out different.
+
+BEGIN;
 
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('now');
-INSERT INTO TIMESTAMPTZ_TBL VALUES ('current');
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('today');
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('yesterday');
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('tomorrow');
@@ -17,7 +26,9 @@ INSERT INTO TIMESTAMPTZ_TBL VALUES ('tomorrow zulu');
 SELECT count(*) AS One FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp with time zone 'today';
 SELECT count(*) AS One FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp with time zone 'tomorrow';
 SELECT count(*) AS One FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp with time zone 'yesterday';
-SELECT count(*) AS None FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp with time zone 'now';
+SELECT count(*) AS One FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp(2) with time zone 'now';
+
+COMMIT;
 
 DELETE FROM TIMESTAMPTZ_TBL;
 
@@ -26,7 +37,8 @@ BEGIN;
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('now');
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('now');
 SELECT count(*) AS two FROM TIMESTAMPTZ_TBL WHERE d1 = timestamp(2) with time zone 'now';
-END;
+COMMIT;
+
 DELETE FROM TIMESTAMPTZ_TBL;
 
 -- Special values
@@ -35,6 +47,7 @@ INSERT INTO TIMESTAMPTZ_TBL VALUES ('infinity');
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('epoch');
 -- Obsolete special values
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('invalid');
+INSERT INTO TIMESTAMPTZ_TBL VALUES ('current');
 
 -- Postgres v6.0 standard output format
 INSERT INTO TIMESTAMPTZ_TBL VALUES ('Mon Feb 10 17:32:01 1997 PST');