Add set_system_time function

Makefile

@@ -11,6 +11,7 @@ performance_test:
 	@echo "\nDB Setup\n"
 	@createdb temporal_tables_test
 	@psql temporal_tables_test -q -f versioning_function.sql
+	@psql temporal_tables_test -q -f system_time_function.sql
 	@psql temporal_tables_test -q -f test/performance/setup.sql
 
 	@echo "\nRun Test\n"
@@ -32,6 +33,7 @@ performance_test_nochecks:
 	@echo "\nDB Setup\n"
 	@createdb temporal_tables_test
 	@psql temporal_tables_test -q -f versioning_function_nochecks.sql
+	@psql temporal_tables_test -q -f system_time_function.sql
 	@psql temporal_tables_test -q -f test/performance/setup.sql
 
 	@echo "\nRun Test for NOCHECKS version\n"

README.md

@@ -8,8 +8,6 @@ The goal is to be able to use it on AWS RDS and other hosted solutions, where us
 
 The version provided in `versioning_function.sql` is a drop-in replacement.
 
-It works exactly the same way, but lacks the [set_system_time](https://github.com/arkhipov/temporal_tables#advanced-usage) function to work with the current time.
-
 The version in `versioning_function_nochecks.sql` is similar to the previous one, but all validation checks have been removed. This version is 2x faster than the normal one, but more dangerous and prone to errors.
 
 With time, added some new functionality diverging from the original implementations. New functionalities are however still retro-compatible:
@@ -27,6 +25,11 @@ createdb temporal_test
 psql temporal_test < versioning_function.sql
 ```
 
+If you would like to have `set_system_time` function available (more details [below](#system-time)) you should run the following as well:
+```sh
+psql temporal_test < system_time_function.sql
+```
+
 Connect to the db:
 
 ```
@@ -82,7 +85,7 @@ DELETE FROM subscriptions WHERE name = 'test1';
 
 Take some time between a query and the following, otherwise the difference in the time periods won't be noticeable.
 
-After all the query are completed, you should check the tables content.
+After all the queries are completed, you should check the tables content.
 
 ```sql
 SELECT * FROM subscriptions;
@@ -91,7 +94,7 @@ SELECT * FROM subscriptions;
 Should return 0 rows
 
 ```sql
-SELECT * FROM subscriptions_history
+SELECT * FROM subscriptions_history;
 ```
 
 Should return something similar to:
@@ -102,6 +105,57 @@ Should return something similar to:
 | test1 | updated       | ["2017-08-01 16:09:54.984179+02","2017-08-01 16:10:08.880571+02") |
 | test1 | updated twice | ["2017-08-01 16:10:08.880571+02","2017-08-01 16:10:17.33659+02")  |
 
+<a name="system-time"></a>
+## Setting custom system time
+If you want to take advantage of setting a custom system time you can use the `set_system_time` function. It is a port of the original [set_system_time](https://github.com/arkhipov/temporal_tables#advanced-usage).
+The function accepts string representation of timestamp in the following format: `YYYY-MM-DD HH:MI:SS.MS.US` - where hours are in 24-hour format 00-23 and the MS (milliseconds) and US (microseconds) portions are optional. 
+Same as the original function, calling it with `null` will reset to default setting (using the CURRENT_TIMESTAMP):
+
+```sql
+SELECT set_system_time(null);
+```
+Below is an example on how to use this function (continues using the example from above):
+
+Create the set_system_time function:
+
+```sh
+psql temporal_test < system_time_function.sql
+```
+
+Set a custom value for the system time:
+```sql
+SELECT set_system_time('1999-12-31 23:59:59');
+```
+
+Now test with some data:
+
+```sql
+INSERT INTO subscriptions (name, state) VALUES ('test2', 'inserted');
+UPDATE subscriptions SET state = 'updated' WHERE name = 'test2';
+UPDATE subscriptions SET state = 'updated twice' WHERE name = 'test2';
+DELETE FROM subscriptions WHERE name = 'test2';
+```
+
+Take some time between a query and the following, otherwise the difference in the time periods won't be noticeable.
+
+After all the queries are completed, you should check the `subscriptions_history` table content:
+
+```sql
+SELECT * FROM subscriptions_history;
+```
+
+Should return something similar to:
+
+name  |     state     |                            sys_period
+----- | ------------- | -------------------------------------------------------------------
+ test1 | inserted      | ["2017-08-01 16:09:45.542983+02","2017-08-01 16:09:54.984179+02")
+ test1 | updated       | ["2017-08-01 16:09:54.984179+02","2017-08-01 16:10:08.880571+02")
+ test1 | updated twice | ["2017-08-01 16:10:08.880571+02","2017-08-01 16:10:17.33659+02")
+ test2 | inserted      | ["1999-12-31 23:59:59+01","1999-12-31 23:59:59.000001+01")
+ test2 | updated       | ["1999-12-31 23:59:59.000001+01","1999-12-31 23:59:59.000002+01")
+ test2 | updated twice | ["1999-12-31 23:59:59.000002+01","1999-12-31 23:59:59.000003+01")
+
+
 <a name="additional-features"></a>
 
 ## Additional features

scripts/update-version.js

@@ -4,7 +4,7 @@ console.log("UPDATING VERSION ...");
 
 const packageJson = require("../package.json");
 const newVersion = packageJson.version;
-const files = ["versioning_function", "versioning_function_nochecks"];
+const files = ["versioning_function", "versioning_function_nochecks", "system_time_function"];
 
 files.forEach((fileName) => {
   const data = readFileSync(__dirname + `/../${fileName}.sql`, {

system_time_function.sql

@@ -0,0 +1,27 @@
+-- version 0.5.0
+
+CREATE OR REPLACE FUNCTION set_system_time(user_timestamp text)
+RETURNS text AS $$
+DECLARE
+  custom_system_time text;
+BEGIN
+  IF user_timestamp IS NULL THEN
+    custom_system_time := null;
+  ELSE
+    PERFORM 
+      REGEXP_MATCHES(user_timestamp, 
+          '(\d){4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2]\d|3[0-1]) ([0-1]\d|2[0-3]):[0-5]\d:[0-5]\d(\.\d{1,3})?(\.\d{1,6})?', 
+          'g');
+    IF NOT FOUND THEN
+      RAISE 'You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)';
+    ELSE
+      custom_system_time := user_timestamp;
+    END IF;
+  END IF;
+
+  PERFORM set_config('user_defined.system_time', custom_system_time, false);
+
+  return custom_system_time;
+
+END; 
+$$ LANGUAGE plpgsql;

test/expected/invalid_set_system_time.out

@@ -0,0 +1,31 @@
+-- Invalid dates
+SELECT set_system_time('2022-13-01 22:59:59');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+SELECT set_system_time('22-13-01 22:59:59');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+SELECT set_system_time('2022-12-99 22:59:59');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+-- Invalid time
+SELECT set_system_time('2022-01-11 99:59:59');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+SELECT set_system_time('2022-01-11 22:99:59');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+SELECT set_system_time('2022-01-11 22:59:99');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+SELECT set_system_time('2022-01-11 22:59');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+SELECT set_system_time('2022-01-11 22');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+-- Invalid values
+SELECT set_system_time('Invalid string value');
+ERROR:  You must enter a timestamp in the following format: YYYY-MM-DD HH24:MI:SS.MS.US (hours are in 24-hour format 00-23, MS and US are optional)
+SELECT set_system_time(123);
+ERROR:  function set_system_time(integer) does not exist
+LINE 1: SELECT set_system_time(123);
+               ^
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT set_system_time();
+ERROR:  function set_system_time() does not exist
+LINE 1: SELECT set_system_time();
+               ^
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

test/expected/non_equality_types.out

@@ -1,7 +1,7 @@
-SET client_min_messages TO error
-CREATE TABLE non_equality_types (json json, sys_period tstzrange)
+SET client_min_messages TO error;
+CREATE TABLE non_equality_types (json json, sys_period tstzrange);
 CREATE TRIGGER versioning_trigger
 BEFORE INSERT OR UPDATE OR DELETE ON non_equality_types
-FOR EACH ROW EXECUTE PROCEDURE versioning('sys_period', 'non_equality_types', false)
-INSERT INTO non_equality_types VALUES ('{"a":1}'::json)
-UPDATE non_equality_types SET json = '{"a":2}'::json WHERE 1=1
+FOR EACH ROW EXECUTE PROCEDURE versioning('sys_period', 'non_equality_types', false);
+INSERT INTO non_equality_types VALUES ('{"a":1}'::json);
+UPDATE non_equality_types SET json = '{"a":2}'::json WHERE 1=1;

test/expected/non_equality_types_unchanged_values.out

@@ -1,9 +1,8 @@
-SET client_min_messages TO error
-CREATE TABLE non_equality_types_unchanged_values (json json, sys_period tstzrange)
+SET client_min_messages TO error;
+CREATE TABLE non_equality_types_unchanged_values (json json, sys_period tstzrange);
 CREATE TRIGGER versioning_trigger
 BEFORE INSERT OR UPDATE OR DELETE ON non_equality_types_unchanged_values
-FOR EACH ROW EXECUTE PROCEDURE versioning('sys_period', 'non_equality_types_unchanged_values', false, true)
-INSERT INTO non_equality_types_unchanged_values VALUES ('{"a":1}'::json)
-UPDATE non_equality_types_unchanged_values SET json = '{"a":2}'::json WHERE 1=1
+FOR EACH ROW EXECUTE PROCEDURE versioning('sys_period', 'non_equality_types_unchanged_values', false, true);
+INSERT INTO non_equality_types_unchanged_values VALUES ('{"a":1}'::json);
+UPDATE non_equality_types_unchanged_values SET json = '{"a":2}'::json WHERE 1=1;
 ERROR:  could not identify an equality operator for type json
-CONTEXT:  PL/pgSQL function versioning() line 39 at IF

test/expected/set_system_time.out

@@ -0,0 +1,78 @@
+CREATE TABLE versioning (a bigint, "b b" date, sys_period tstzrange);
+-- Insert some data before versioning is enabled.
+INSERT INTO versioning (a, sys_period) VALUES (1, tstzrange('-infinity', NULL));
+INSERT INTO versioning (a, sys_period) VALUES (2, tstzrange('2000-01-01', NULL));
+CREATE TABLE versioning_history (a bigint, c date, sys_period tstzrange);
+CREATE TRIGGER versioning_trigger
+BEFORE INSERT OR UPDATE OR DELETE ON versioning
+FOR EACH ROW EXECUTE PROCEDURE versioning('sys_period', 'versioning_history', false);
+-- Insert.
+BEGIN;
+SELECT set_system_time('2001-01-01 22:59:59.001.000234');
+   set_system_time   
+--------------------------------
+ 2001-01-01 22:59:59.001.000234
+(1 row)
+
+INSERT INTO versioning (a) VALUES (3);
+SELECT * FROM versioning_history;
+ a | c | sys_period 
+---+---+------------
+(0 rows)
+
+COMMIT;
+-- Update.
+BEGIN;
+UPDATE versioning SET a = 4 WHERE a = 3;
+SELECT * FROM versioning_history;
+ a | c |         sys_period          
+---+---+------------------------------------
+ 3 |   | (,"2001-01-01 22:59:59.001234+01")
+(1 row)
+
+COMMIT;
+-- Reset system time and do multiple updates.
+BEGIN;
+UPDATE versioning SET a = 5 WHERE a = 4;
+UPDATE versioning SET "b b" = '2012-01-01' WHERE a = 5;
+SELECT * FROM versioning_history;
+ a | c |         sys_period          
+---+---+------------------------------------
+ 3 |   | (,"2001-01-01 22:59:59.001234+01")
+ 4 |   | (,"2001-01-01 22:59:59.001234+01")
+(2 rows)
+
+COMMIT;
+-- Delete.
+BEGIN;
+SELECT set_system_time('2022-01-11 12:00:00.000.000000');
+   set_system_time   
+--------------------------------
+ 2022-01-11 12:00:00.000.000000
+(1 row)
+
+DELETE FROM versioning WHERE a = 4;
+SELECT * FROM versioning_history;
+ a | c |         sys_period          
+---+---+------------------------------------
+ 3 |   | (,"2001-01-01 22:59:59.001234+01")
+ 4 |   | (,"2001-01-01 22:59:59.001234+01")
+(2 rows)
+
+END;
+-- Delete.
+BEGIN;
+DELETE FROM versioning;
+SELECT * FROM versioning_history;
+ a | c |         sys_period          
+---+---+------------------------------------
+ 3 |   | (,"2001-01-01 22:59:59.001234+01")
+ 4 |   | (,"2001-01-01 22:59:59.001234+01")
+ 1 |   | (,"2022-01-11 12:00:00+01")
+ 2 |   | (,"2022-01-11 12:00:00+01")
+ 5 |   | (,"2022-01-11 12:00:00+01")
+(5 rows)
+
+END;
+DROP TABLE versioning;
+DROP TABLE versioning_history;

test/runTest.sh

@@ -2,6 +2,7 @@
 
 createdb temporal_tables_test
 psql temporal_tables_test -q -f versioning_function.sql
+psql temporal_tables_test -q -f system_time_function.sql
 
 mkdir -p test/result
 
@@ -10,7 +11,9 @@ TESTS="
   invalid_system_period_values invalid_system_period invalid_types
   versioning upper_case structure combinations
   different_schema unchanged_values unchanged_version_values
-  non_equality_types non_equality_types_unchanged_values"
+  non_equality_types non_equality_types_unchanged_values
+  set_system_time invalid_set_system_time
+  "
 
 for name in $TESTS; do
   echo ""

test/runTestNochecks.sh

@@ -2,6 +2,7 @@
 
 createdb temporal_tables_test
 psql temporal_tables_test -q -f versioning_function_nochecks.sql
+psql temporal_tables_test -q -f system_time_function.sql
 
 mkdir -p test/result
 

test/sql/invalid_set_system_time.sql

@@ -0,0 +1,16 @@
+-- Invalid dates
+SELECT set_system_time('2022-13-01 22:59:59');
+SELECT set_system_time('22-13-01 22:59:59');
+SELECT set_system_time('2022-12-99 22:59:59');
+
+-- Invalid time
+SELECT set_system_time('2022-01-11 99:59:59');
+SELECT set_system_time('2022-01-11 22:99:59');
+SELECT set_system_time('2022-01-11 22:59:99');
+SELECT set_system_time('2022-01-11 22:59');
+SELECT set_system_time('2022-01-11 22');
+
+-- Invalid values
+SELECT set_system_time('Invalid string value');
+SELECT set_system_time(123);
+SELECT set_system_time();

test/sql/set_system_time.sql

@@ -0,0 +1,64 @@
+CREATE TABLE versioning (a bigint, "b b" date, sys_period tstzrange);
+
+-- Insert some data before versioning is enabled.
+INSERT INTO versioning (a, sys_period) VALUES (1, tstzrange('-infinity', NULL));
+INSERT INTO versioning (a, sys_period) VALUES (2, tstzrange('2000-01-01', NULL));
+
+CREATE TABLE versioning_history (a bigint, c date, sys_period tstzrange);
+
+CREATE TRIGGER versioning_trigger
+BEFORE INSERT OR UPDATE OR DELETE ON versioning
+FOR EACH ROW EXECUTE PROCEDURE versioning('sys_period', 'versioning_history', false);
+
+-- Insert.
+BEGIN;
+
+SELECT set_system_time('2001-01-01 22:59:59.001.000234');
+
+INSERT INTO versioning (a) VALUES (3);
+
+SELECT * FROM versioning_history;
+
+COMMIT;
+
+-- Update.
+BEGIN;
+
+UPDATE versioning SET a = 4 WHERE a = 3;
+
+SELECT * FROM versioning_history;
+
+COMMIT;
+
+-- Reset system time and do multiple updates.
+BEGIN;
+
+UPDATE versioning SET a = 5 WHERE a = 4;
+UPDATE versioning SET "b b" = '2012-01-01' WHERE a = 5;
+
+SELECT * FROM versioning_history;
+
+COMMIT;
+
+-- Delete.
+BEGIN;
+
+SELECT set_system_time('2022-01-11 12:00:00.000.000000');
+
+DELETE FROM versioning WHERE a = 4;
+
+SELECT * FROM versioning_history;
+
+END;
+
+-- Delete.
+BEGIN;
+
+DELETE FROM versioning;
+
+SELECT * FROM versioning_history;
+
+END;
+
+DROP TABLE versioning;
+DROP TABLE versioning_history;