Back out the session_start and session_end hooks feature.

It's become apparent during testing that there are problems with at
least the testing regime. I don't think we should have it without a
working test regime, and the difficulties might indicate implementation
problems anyway, so I'm backing out the whole thing until that's sorted
out.

This reverts commits 7459484 9989f92 cd8ce3a

14 files changed, 0 insertions, 239 deletions

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index d3156ad49ef..05c5c194ec6 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -169,9 +169,6 @@ static ProcSignalReason RecoveryConflictReason;
 static MemoryContext row_description_context = NULL;
 static StringInfoData row_description_buf;
 
-/* Hook for plugins to get control at start of session */
-session_start_hook_type session_start_hook = NULL;
-
 /* ----------------------------------------------------------------
  *		decls for routines only used in this file
  * ----------------------------------------------------------------
@@ -3860,9 +3857,6 @@ PostgresMain(int argc, char *argv[],
 	if (!IsUnderPostmaster)
 		PgStartTime = GetCurrentTimestamp();
 
-	if (session_start_hook)
-		(*session_start_hook) ();
-
 	/*
 	 * POSTGRES main processing loop begins here
 	 *
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 16ec376b221..20f1d279e9c 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -76,8 +76,6 @@ static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
 
-/* Hook for plugins to get control at end of session */
-session_end_hook_type session_end_hook = NULL;
 
 /*** InitPostgres support ***/
 
@@ -1156,10 +1154,6 @@ ShutdownPostgres(int code, Datum arg)
 	 * them explicitly.
 	 */
 	LockReleaseAll(USER_LOCKMETHOD, true);
-
-	/* Hook at session end */
-	if (session_end_hook)
-		(*session_end_hook) ();
 }
 
 
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 9f05bfb4ab5..f8c535c91e3 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -35,13 +35,6 @@ extern PGDLLIMPORT const char *debug_query_string;
 extern int	max_stack_depth;
 extern int	PostAuthDelay;
 
-/* Hook for plugins to get control at start and end of session */
-typedef void (*session_start_hook_type) (void);
-typedef void (*session_end_hook_type) (void);
-
-extern PGDLLIMPORT session_start_hook_type session_start_hook;
-extern PGDLLIMPORT session_end_hook_type session_end_hook;
-
 /* GUC-configurable parameters */
 
 typedef enum
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 7246552d386..b7ed0af021f 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -15,7 +15,6 @@ SUBDIRS = \
 		  test_pg_dump \
 		  test_rbtree \
 		  test_rls_hooks \
-		  test_session_hooks \
 		  test_shm_mq \
 		  worker_spi
 
diff --git a/src/test/modules/test_session_hooks/.gitignore b/src/test/modules/test_session_hooks/.gitignore
deleted file mode 100644
index 5dcb3ff9723..00000000000
--- a/src/test/modules/test_session_hooks/.gitignore
+++ /dev/null
@@ -1,4 +0,0 @@
-# Generated subdirectories
-/log/
-/results/
-/tmp_check/
diff --git a/src/test/modules/test_session_hooks/Makefile b/src/test/modules/test_session_hooks/Makefile
deleted file mode 100644
index 636ae61c0e1..00000000000
--- a/src/test/modules/test_session_hooks/Makefile
+++ /dev/null
@@ -1,25 +0,0 @@
-# src/test/modules/test_session_hooks/Makefile
-
-MODULES = test_session_hooks
-PGFILEDESC = "test_session_hooks - Test session hooks with an extension"
-
-EXTENSION = test_session_hooks
-DATA = test_session_hooks--1.0.sql
-
-REGRESS = test_session_hooks
-REGRESS_OPTS = --temp-config=$(top_srcdir)/src/test/modules/test_session_hooks/session_hooks.conf
-
-ifdef USE_PGXS
-PG_CONFIG = pg_config
-PGXS := $(shell $(PG_CONFIG) --pgxs)
-include $(PGXS)
-else
-subdir = src/test/modules/test_session_hooks
-top_builddir = ../../../..
-include $(top_builddir)/src/Makefile.global
-include $(top_srcdir)/contrib/contrib-global.mk
-endif
-
-# override installcheck - this module requires preloading the test module
-installcheck:
-	@echo Cannot run $@ for test_session_hooks. Run "'make check'" instead.
diff --git a/src/test/modules/test_session_hooks/README b/src/test/modules/test_session_hooks/README
deleted file mode 100644
index 9cb42020c64..00000000000
--- a/src/test/modules/test_session_hooks/README
+++ /dev/null
@@ -1,2 +0,0 @@
-test_session_hooks is an example of how to use session start and end
-hooks.
diff --git a/src/test/modules/test_session_hooks/expected/test_session_hooks.out b/src/test/modules/test_session_hooks/expected/test_session_hooks.out
deleted file mode 100644
index be1b94953c5..00000000000
--- a/src/test/modules/test_session_hooks/expected/test_session_hooks.out
+++ /dev/null
@@ -1,31 +0,0 @@
-CREATE ROLE regress_sess_hook_usr1 SUPERUSER LOGIN;
-CREATE ROLE regress_sess_hook_usr2 SUPERUSER LOGIN;
-\set prevdb :DBNAME
-\set prevusr :USER
-CREATE TABLE session_hook_log(id SERIAL, dbname TEXT, username TEXT, hook_at TEXT);
-SELECT * FROM session_hook_log ORDER BY id;
- id | dbname | username | hook_at 
-----+--------+----------+---------
-(0 rows)
-
-\c :prevdb regress_sess_hook_usr1
-SELECT * FROM session_hook_log ORDER BY id;
- id | dbname | username | hook_at 
-----+--------+----------+---------
-(0 rows)
-
-\c :prevdb regress_sess_hook_usr2
-SELECT * FROM session_hook_log ORDER BY id;
- id |       dbname       |        username        | hook_at 
-----+--------------------+------------------------+---------
-  1 | contrib_regression | regress_sess_hook_usr2 | START
-(1 row)
-
-\c :prevdb :prevusr
-SELECT * FROM session_hook_log ORDER BY id;
- id |       dbname       |        username        | hook_at 
-----+--------------------+------------------------+---------
-  1 | contrib_regression | regress_sess_hook_usr2 | START
-  2 | contrib_regression | regress_sess_hook_usr2 | END
-(2 rows)
-
diff --git a/src/test/modules/test_session_hooks/session_hooks.conf b/src/test/modules/test_session_hooks/session_hooks.conf
deleted file mode 100644
index fc62b4adef0..00000000000
--- a/src/test/modules/test_session_hooks/session_hooks.conf
+++ /dev/null
@@ -1,2 +0,0 @@
-shared_preload_libraries = 'test_session_hooks'
-test_session_hooks.username = regress_sess_hook_usr2
diff --git a/src/test/modules/test_session_hooks/sql/test_session_hooks.sql b/src/test/modules/test_session_hooks/sql/test_session_hooks.sql
deleted file mode 100644
index 5e0864753d9..00000000000
--- a/src/test/modules/test_session_hooks/sql/test_session_hooks.sql
+++ /dev/null
@@ -1,12 +0,0 @@
-CREATE ROLE regress_sess_hook_usr1 SUPERUSER LOGIN;
-CREATE ROLE regress_sess_hook_usr2 SUPERUSER LOGIN;
-\set prevdb :DBNAME
-\set prevusr :USER
-CREATE TABLE session_hook_log(id SERIAL, dbname TEXT, username TEXT, hook_at TEXT);
-SELECT * FROM session_hook_log ORDER BY id;
-\c :prevdb regress_sess_hook_usr1
-SELECT * FROM session_hook_log ORDER BY id;
-\c :prevdb regress_sess_hook_usr2
-SELECT * FROM session_hook_log ORDER BY id;
-\c :prevdb :prevusr
-SELECT * FROM session_hook_log ORDER BY id;
diff --git a/src/test/modules/test_session_hooks/test_session_hooks--1.0.sql b/src/test/modules/test_session_hooks/test_session_hooks--1.0.sql
deleted file mode 100644
index 16bcee9882e..00000000000
--- a/src/test/modules/test_session_hooks/test_session_hooks--1.0.sql
+++ /dev/null
@@ -1,4 +0,0 @@
-/* src/test/modules/test_hook_session/test_hook_session--1.0.sql */
-
--- complain if script is sourced in psql, rather than via CREATE EXTENSION
-\echo Use "CREATE EXTENSION test_hook_session" to load this file. \quit
diff --git a/src/test/modules/test_session_hooks/test_session_hooks.c b/src/test/modules/test_session_hooks/test_session_hooks.c
deleted file mode 100644
index 4e2eef183e4..00000000000
--- a/src/test/modules/test_session_hooks/test_session_hooks.c
+++ /dev/null
@@ -1,134 +0,0 @@
-/* -------------------------------------------------------------------------
- *
- * test_session_hooks.c
- * 		Code for testing SESSION hooks.
- *
- * Copyright (c) 2010-2017, PostgreSQL Global Development Group
- *
- * IDENTIFICATION
- *		src/test/modules/test_session_hooks/test_session_hooks.c
- *
- * -------------------------------------------------------------------------
- */
-#include "postgres.h"
-
-#include "access/xact.h"
-#include "commands/dbcommands.h"
-#include "executor/spi.h"
-#include "lib/stringinfo.h"
-#include "miscadmin.h"
-#include "tcop/tcopprot.h"
-#include "utils/snapmgr.h"
-#include "utils/builtins.h"
-
-PG_MODULE_MAGIC;
-
-/* Entry point of library loading/unloading */
-void		_PG_init(void);
-void		_PG_fini(void);
-
-/* GUC variables */
-static char *session_hook_username = "postgres";
-
-/* Original Hook */
-static session_start_hook_type prev_session_start_hook = NULL;
-static session_end_hook_type prev_session_end_hook = NULL;
-
-static void
-register_session_hook(const char *hook_at)
-{
-	const char *username;
-
-	StartTransactionCommand();
-	SPI_connect();
-	PushActiveSnapshot(GetTransactionSnapshot());
-
-	username = GetUserNameFromId(GetUserId(), false);
-
-	/* Register log just for configured username */
-	if (!strcmp(username, session_hook_username))
-	{
-		const char *dbname;
-		int ret;
-		StringInfoData	buf;
-
-		dbname = get_database_name(MyDatabaseId);
-
-		initStringInfo(&buf);
-
-		appendStringInfo(&buf, "INSERT INTO session_hook_log (dbname, username, hook_at) ");
-		appendStringInfo(&buf, "VALUES ('%s', '%s', '%s');",
-			dbname, username, hook_at);
-
-		ret = SPI_exec(buf.data, 0);
-		if (ret != SPI_OK_INSERT)
-			elog(ERROR, "SPI_execute failed: error code %d", ret);
-	}
-
-	SPI_finish();
-	PopActiveSnapshot();
-	CommitTransactionCommand();
-}
-
-/* sample session start hook function */
-static void
-sample_session_start_hook()
-{
-	/* Hook just normal backends */
-	if (MyBackendId != InvalidBackendId)
-	{
-		(void) register_session_hook("START");
-
-		if (prev_session_start_hook)
-			prev_session_start_hook();
-	}
-}
-
-/* sample session end hook function */
-static void
-sample_session_end_hook()
-{
-	/* Hook just normal backends */
-	if (MyBackendId != InvalidBackendId)
-	{
-		if (prev_session_end_hook)
-			prev_session_end_hook();
-
-		(void) register_session_hook("END");
-	}
-}
-
-/*
- * Module Load Callback
- */
-void
-_PG_init(void)
-{
-	/* Save Hooks for Unload */
-	prev_session_start_hook = session_start_hook;
-	prev_session_end_hook = session_end_hook;
-
-	/* Set New Hooks */
-	session_start_hook = sample_session_start_hook;
-	session_end_hook = sample_session_end_hook;
-
-	/* Load GUCs */
-	DefineCustomStringVariable("test_session_hooks.username",
-							   "Username to register log on session start or end",
-							   NULL,
-							   &session_hook_username,
-							   "postgres",
-							   PGC_SIGHUP,
-							   0, NULL, NULL, NULL);
-}
-
-/*
- * Module Unload Callback
- */
-void
-_PG_fini(void)
-{
-	/* Uninstall Hooks */
-	session_start_hook = prev_session_start_hook;
-	session_end_hook = prev_session_end_hook;
-}
diff --git a/src/test/modules/test_session_hooks/test_session_hooks.control b/src/test/modules/test_session_hooks/test_session_hooks.control
deleted file mode 100644
index 7d7ef9f3f4a..00000000000
--- a/src/test/modules/test_session_hooks/test_session_hooks.control
+++ /dev/null
@@ -1,3 +0,0 @@
-comment = 'Test start/end hook session with an extension'
-default_version = '1.0'
-relocatable = true
diff --git a/src/tools/msvc/vcregress.pl b/src/tools/msvc/vcregress.pl
index 41f7832e5a6..719fe830476 100644
--- a/src/tools/msvc/vcregress.pl
+++ b/src/tools/msvc/vcregress.pl
@@ -383,8 +383,6 @@ sub modulescheck
 	my $mstat = 0;
 	foreach my $module (glob("*"))
 	{
-		# test_session_hooks can't run installcheck, so skip it here
-		next if $module eq 'test_session_hooks';
 		subdircheck("$topdir/src/test/modules", $module);
 		my $status = $? >> 8;
 		$mstat ||= $status;