Added version_sql() function and consistency check of sql version

bin/pg_repack.c

@@ -240,15 +240,18 @@ repack_one_database(const char *orderby, const char *table, char *errbuf, size_t
 	reconnect(ERROR);
 
 	/* Query the extension version. Exit if no match */
-	res = execute_elevel("select repack.version()", 0, NULL, DEBUG2);
+	res = execute_elevel("select repack.version(), repack.version_sql()",
+		0, NULL, DEBUG2);
 	if (PQresultStatus(res) == PGRES_TUPLES_OK)
 	{
 		const char	   *libver;
 		char			buf[64];
 
 		/* the string is something like "pg_repack 1.1.7" */
-		libver = getstr(res, 0, 0);
 		snprintf(buf, sizeof(buf), "%s %s", PROGRAM_NAME, PROGRAM_VERSION);
+
+		/* check the version of the C library */
+		libver = getstr(res, 0, 0);
 		if (0 != strcmp(buf, libver))
 		{
 			if (errbuf)
@@ -257,6 +260,17 @@ repack_one_database(const char *orderby, const char *table, char *errbuf, size_t
 					buf, libver);
 			goto cleanup;
 		}
+
+		/* check the version of the SQL extension */
+		libver = getstr(res, 0, 1);
+		if (0 != strcmp(buf, libver))
+		{
+			if (errbuf)
+				snprintf(errbuf, errsize,
+					"extension '%s' required, found extension '%s'",
+					buf, libver);
+			goto cleanup;
+		}
 	}
 	else
 	{

doc/pg_repack.rst

@@ -290,6 +290,13 @@ ERROR: program 'pg_repack V1' does not match database library 'pg_repack V2'
     database; if they are what expected you may need to repeat pg_repack
     installation.
 
+ERROR: extension 'pg_repack V1' required, found extension 'pg_repack V2'
+    The SQL extension found in the database does not match the version
+    required by the pg_repack program.
+
+    You should drop the extension from the database and reload it as described
+    in the installation_ section.
+
 ERROR: relation "table" has no primary key
     The target table doesn't have PRIMARY KEY.
 

lib/Makefile

@@ -30,7 +30,7 @@ DATA_built = pg_repack.sql
 DATA = uninstall_pg_repack.sql
 endif
 
-USE_PGXS = 1	# use pgxs if not in contrib directory
+USE_PGXS = 1
 PGXS := $(shell $(PG_CONFIG) --pgxs)
 include $(PGXS)
 
@@ -40,11 +40,12 @@ LIBS := $(filter-out -lxslt, $(LIBS))
 
 pg_repack.sql: pg_repack.sql.in
 	echo "BEGIN;\n" > $@; \
-	sed 's,MODULE_PATHNAME,$$libdir/$(MODULE_big),g' $< >> $@; \
+	sed 's,MODULE_PATHNAME,$$libdir/$(MODULE_big),g' $< \
+	| sed 's,REPACK_VERSION,$(REPACK_VERSION),g' >> $@; \
 	echo "\nCOMMIT;" >> $@;
 
 pg_repack--$(REPACK_VERSION).sql: pg_repack.sql.in
-	cat $< > $@;
+	sed 's,REPACK_VERSION,$(REPACK_VERSION),g' $< > $@;
 
 pg_repack.control: pg_repack.control.in
 	sed 's,REPACK_VERSION,$(REPACK_VERSION),g' $< > $@

lib/pg_repack.sql.in

@@ -12,6 +12,10 @@ CREATE FUNCTION repack.version() RETURNS text AS
 'MODULE_PATHNAME', 'repack_version'
 LANGUAGE C IMMUTABLE STRICT;
 
+CREATE FUNCTION repack.version_sql() RETURNS text AS
+$$SELECT 'pg_repack REPACK_VERSION'::text$$
+LANGUAGE SQL IMMUTABLE STRICT;
+
 CREATE AGGREGATE repack.array_accum (
     sfunc = array_append,
     basetype = anyelement,