[Erica Zhang <ericazhangy@qq.com>]

Hi All,
On the master branch, it is possible to install multiple versions of pg_stat_statements with CREATE EXTENSION, but all the tests in sql/ on look at the latest version available, without testing past compatibility. 

Since we support to install lowest version 1.4 currently, add some tests to verify compatibility, upgrade from lower versions of pg_stat_statements.

Attachments:

add_test_for_pg_stat_statements.patch (application/octet-stream, 7.2K) download
diff --git a/contrib/pg_stat_statements/expected/pg_stat_statements.out b/contrib/pg_stat_statements/expected/pg_stat_statements.out
index 16158525ca..cde6f29444 100644
--- a/contrib/pg_stat_statements/expected/pg_stat_statements.out
+++ b/contrib/pg_stat_statements/expected/pg_stat_statements.out
@@ -877,3 +877,137 @@ SELECT dealloc FROM pg_stat_statements_info;
 (1 row)

 DROP EXTENSION pg_stat_statements;
+--
+-- Verify compatible with older versions.
+-- Currently the lowest version from which upgrade is supported is 1.4.
+--
+CREATE EXTENSION pg_stat_statements with version '1.4';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.4';
+        name        | default_version | installed_version |                                comment
+--------------------+-----------------+-------------------+------------------------------------------------------------------------
+ pg_stat_statements | 1.9             | 1.4               | track planning and execution statistics of all SQL statements executed
+(1 row)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT count(query) FROM pg_stat_statements;
+ count
+-------
+     2
+(1 row)
+
+---
+--- Upgrade extension to 1.5
+---
+AlTER EXTENSION pg_stat_statements update to '1.5';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.5';
+        name        | default_version | installed_version |                                comment
+--------------------+-----------------+-------------------+------------------------------------------------------------------------
+ pg_stat_statements | 1.9             | 1.5               | track planning and execution statistics of all SQL statements executed
+(1 row)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT count(query) FROM pg_stat_statements;
+ count
+-------
+     2
+(1 row)
+
+---
+--- Upgrade extension to 1.6
+---
+AlTER EXTENSION pg_stat_statements update to '1.6';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.6';
+        name        | default_version | installed_version |                                comment
+--------------------+-----------------+-------------------+------------------------------------------------------------------------
+ pg_stat_statements | 1.9             | 1.6               | track planning and execution statistics of all SQL statements executed
+(1 row)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT count(query) FROM pg_stat_statements;
+ count
+-------
+     2
+(1 row)
+
+---
+--- Upgrade extension to 1.7
+---
+AlTER EXTENSION pg_stat_statements update to '1.7';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.7';
+        name        | default_version | installed_version |                                comment
+--------------------+-----------------+-------------------+------------------------------------------------------------------------
+ pg_stat_statements | 1.9             | 1.7               | track planning and execution statistics of all SQL statements executed
+(1 row)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT count(query) FROM pg_stat_statements;
+ count
+-------
+     2
+(1 row)
+
+---
+--- Upgrade extension to 1.8
+---
+AlTER EXTENSION pg_stat_statements update to '1.8';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.8';
+        name        | default_version | installed_version |                                comment
+--------------------+-----------------+-------------------+------------------------------------------------------------------------
+ pg_stat_statements | 1.9             | 1.8               | track planning and execution statistics of all SQL statements executed
+(1 row)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT count(plans) FROM pg_stat_statements;
+ count
+-------
+     2
+(1 row)
+
+---
+--- Upgrade extension to 1.9
+---
+AlTER EXTENSION pg_stat_statements update to '1.9';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.9';
+        name        | default_version | installed_version |                                comment
+--------------------+-----------------+-------------------+------------------------------------------------------------------------
+ pg_stat_statements | 1.9             | 1.9               | track planning and execution statistics of all SQL statements executed
+(1 row)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT dealloc FROM pg_stat_statements_info;
+ dealloc
+---------
+       0
+(1 row)
+
+DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/sql/pg_stat_statements.sql b/contrib/pg_stat_statements/sql/pg_stat_statements.sql
index 6f58d9d0f6..98d8a051b6 100644
--- a/contrib/pg_stat_statements/sql/pg_stat_statements.sql
+++ b/contrib/pg_stat_statements/sql/pg_stat_statements.sql
@@ -365,3 +365,54 @@ SELECT pg_stat_statements_reset();
 SELECT dealloc FROM pg_stat_statements_info;

 DROP EXTENSION pg_stat_statements;
+
+--
+-- Verify compatible with older versions.
+-- Currently the lowest version from which upgrade is supported is 1.4.
+--
+CREATE EXTENSION pg_stat_statements with version '1.4';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.4';
+SELECT pg_stat_statements_reset();
+SELECT count(query) FROM pg_stat_statements;
+
+---
+--- Upgrade extension to 1.5
+---
+AlTER EXTENSION pg_stat_statements update to '1.5';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.5';
+SELECT pg_stat_statements_reset();
+SELECT count(query) FROM pg_stat_statements;
+
+---
+--- Upgrade extension to 1.6
+---
+AlTER EXTENSION pg_stat_statements update to '1.6';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.6';
+SELECT pg_stat_statements_reset();
+SELECT count(query) FROM pg_stat_statements;
+
+---
+--- Upgrade extension to 1.7
+---
+AlTER EXTENSION pg_stat_statements update to '1.7';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.7';
+SELECT pg_stat_statements_reset();
+SELECT count(query) FROM pg_stat_statements;
+
+---
+--- Upgrade extension to 1.8
+---
+AlTER EXTENSION pg_stat_statements update to '1.8';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.8';
+SELECT pg_stat_statements_reset();
+SELECT count(plans) FROM pg_stat_statements;
+
+---
+--- Upgrade extension to 1.9
+---
+AlTER EXTENSION pg_stat_statements update to '1.9';
+SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and installed_version = '1.9';
+SELECT pg_stat_statements_reset();
+SELECT dealloc FROM pg_stat_statements_info;
+
+DROP EXTENSION pg_stat_statements;