PG-1931 Fix returned vaules from C function

Latest version of extension stll may be installed with previous API
verison. So we have to return appropriate data set from C code. This
commit fixes bug that was introduced in PGSM version 2.1 when extension
created with API version 2.0 crashes on data fetch.

pg_stat_monitor.c

@@ -2300,7 +2300,7 @@ pg_stat_monitor_internal(FunctionCallInfo fcinfo,
 		else
 			nulls[i++] = true;
 
-		/* parentid at column number 9 */
+		/* parentid at column number 11 */
 		if (tmpkey.parentid != UINT64CONST(0))
 		{
 			values[i++] = UInt64GetDatum(tmpkey.parentid);
@@ -2312,7 +2312,7 @@ pg_stat_monitor_internal(FunctionCallInfo fcinfo,
 			nulls[i++] = true;
 		}
 
-		/* application_name at column number 15 */
+		/* application_name at column number 13 */
 		if (strlen(tmp.info.application_name) > 0)
 			values[i++] = CStringGetTextDatum(tmp.info.application_name);
 		else
@@ -2445,8 +2445,11 @@ pg_stat_monitor_internal(FunctionCallInfo fcinfo,
 		values[i++] = Int64GetDatumFast(tmp.blocks.temp_blks_written);
 		values[i++] = Float8GetDatumFast(tmp.blocks.shared_blk_read_time);
 		values[i++] = Float8GetDatumFast(tmp.blocks.shared_blk_write_time);
-		values[i++] = Float8GetDatumFast(tmp.blocks.local_blk_read_time);
+		if (api_version >= PGSM_V2_1)
-		values[i++] = Float8GetDatumFast(tmp.blocks.local_blk_write_time);
+		{
+			values[i++] = Float8GetDatumFast(tmp.blocks.local_blk_read_time);
+			values[i++] = Float8GetDatumFast(tmp.blocks.local_blk_write_time);
+		}
 		values[i++] = Float8GetDatumFast(tmp.blocks.temp_blk_read_time);
 		values[i++] = Float8GetDatumFast(tmp.blocks.temp_blk_write_time);
 
@@ -2493,18 +2496,25 @@ pg_stat_monitor_internal(FunctionCallInfo fcinfo,
 			values[i++] = Float8GetDatumFast(tmp.jitinfo.jit_optimization_time);
 			values[i++] = Int64GetDatumFast(tmp.jitinfo.jit_emission_count);
 			values[i++] = Float8GetDatumFast(tmp.jitinfo.jit_emission_time);
-			values[i++] = Int64GetDatumFast(tmp.jitinfo.jit_deform_count);
+			if (api_version >= PGSM_V2_1)
-			values[i++] = Float8GetDatumFast(tmp.jitinfo.jit_deform_time);
+			{
+				/* at column number 64 */
+				values[i++] = Int64GetDatumFast(tmp.jitinfo.jit_deform_count);
+				values[i++] = Float8GetDatumFast(tmp.jitinfo.jit_deform_time);
+			}
 		}
 
-		/* at column number 64 */
+		if (api_version >= PGSM_V2_1)
-		values[i++] = TimestampTzGetDatum(entry->stats_since);
+		{
-		values[i++] = TimestampTzGetDatum(entry->minmax_stats_since);
+			/* at column number 66 */
+			values[i++] = TimestampTzGetDatum(entry->stats_since);
+			values[i++] = TimestampTzGetDatum(entry->minmax_stats_since);
+		}
 
-		/* toplevel at column number 66 */
+		/* toplevel at column number 68 */
 		values[i++] = BoolGetDatum(toplevel);
 
-		/* bucket_done at column number 67 */
+		/* bucket_done at column number 69 */
 		values[i++] = BoolGetDatum(pg_atomic_read_u64(&pgsm->current_wbucket) != bucketid);
 
 		/* clean up and return the tuplestore */

t/034_update.pl

@@ -0,0 +1,54 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use File::Basename;
+use File::Compare;
+use Test::More;
+use lib 't';
+use pgsm;
+
+# Get filename and create out file name and dirs where requried
+PGSM::setup_files_dir(basename($0));
+
+# Create new PostgreSQL node and do initdb
+my $node = PGSM->pgsm_init_pg();
+my $pgdata = $node->data_dir;
+
+# Update postgresql.conf to include/load pg_stat_monitor library
+$node->append_conf('postgresql.conf', "shared_preload_libraries = 'pg_stat_monitor'");
+
+# Start server
+my $rt_value = $node->start;
+ok($rt_value == 1, "Start Server");
+
+# Create EXTENSION version 2.0
+my ($cmdret, $stdout, $stderr) = $node->psql('postgres', 'CREATE EXTENSION pg_stat_monitor VERSION "2.0";', extra_params => ['-a']);
+ok($cmdret == 0, "Create PGSM EXTENSION");
+PGSM::append_to_debug_file($stdout);
+
+# Check that we have some results for version 2.0
+($cmdret, $stdout, $stderr) = $node->psql('postgres', "SELECT * FROM pg_stat_monitor;", extra_params => ['-a']);
+ok($cmdret == 0, "Check PGSM returns some results for version 2.0");
+PGSM::append_to_debug_file($stdout);
+
+# Update EXTENSION to new version 2.1
+($cmdret, $stdout, $stderr) = $node->psql('postgres', 'ALTER EXTENSION pg_stat_monitor UPDATE TO "2.1";', extra_params => ['-a']);
+ok($cmdret == 0, "Update PGSM EXTENSION to new version");
+PGSM::append_to_debug_file($stdout);
+
+# Check that we have some results for version 2.1
+($cmdret, $stdout, $stderr) = $node->psql('postgres', "SELECT * FROM pg_stat_monitor;", extra_params => ['-a']);
+ok($cmdret == 0, "Check PGSM returns some results for version 2.1");
+PGSM::append_to_debug_file($stdout);
+
+# DROP EXTENSION
+$stdout = $node->safe_psql('postgres', 'DROP EXTENSION pg_stat_monitor;', extra_params => ['-a']);
+ok($cmdret == 0, "DROP PGSM EXTENSION");
+PGSM::append_to_debug_file($stdout);
+
+# Stop the server
+$node->stop;
+
+# Done testing for this testcase file.
+done_testing();