Allow auto_explain to be turned on in maintenance jobs

Auto explain allows postgres to log the queries inside of the maintenance jobs and their explain plans. This is a debugging feature.
timescale · Jul 2, 2021 · 0aa7f12 · 0aa7f12
1 parent 4d26951
commit 0aa7f12
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Showing 3 changed files with 39 additions and 8 deletions.
diff --git a/pkg/migrations/migration_files_generated.go b/pkg/migrations/migration_files_generated.go
diff --git a/pkg/migrations/sql/idempotent/base.sql b/pkg/migrations/sql/idempotent/base.sql
@@ -1815,8 +1815,30 @@ CREATE OR REPLACE PROCEDURE SCHEMA_CATALOG.execute_maintenance_job(job_id int, c
 AS $$
 DECLARE
    log_verbose boolean;
+   ae_key text;
+   ae_value text;
+   ae_load boolean := FALSE;
 BEGIN
     log_verbose := coalesce(config->>'log_verbose', 'false')::boolean;
+
+    --if auto_explain enabled in config, turn it on in a best-effort way
+    --i.e. if it fails (most likely due to lack of superuser priviliges) move on anyway.
+    BEGIN
+        FOR ae_key, ae_value IN
+           SELECT * FROM jsonb_each_text(config->'auto_explain')
+        LOOP
+            IF NOT ae_load THEN
+                ae_load := true;
+                LOAD 'auto_explain';
+            END IF;
+
+            PERFORM set_config('auto_explain.'|| ae_key, ae_value, FALSE);
+        END LOOP;
+    EXCEPTION WHEN OTHERS THEN
+        RAISE WARNING 'could not set auto_explain options';
+    END;
+
+
     CALL SCHEMA_PROM.execute_maintenance(log_verbose=>log_verbose);
 END
 $$ LANGUAGE PLPGSQL;

diff --git a/pkg/tests/end_to_end_tests/create_test.go b/pkg/tests/end_to_end_tests/create_test.go
@@ -1618,9 +1618,13 @@ func TestExecuteMaintJob(t *testing.T) {
 		t.Skip("test meaningless without Timescale 2")
 	}
 	withDB(t, *testDatabase, func(dbOwner *pgxpool.Pool, t testing.TB) {
-		db := dbOwner
+		dbSuper, err := pgxpool.Connect(context.Background(), testhelpers.PgConnectURL(*testDatabase, testhelpers.Superuser))
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer dbSuper.Close()
 
-		execJob := func(config *string, configErr bool) {
+		execJob := func(db *pgxpool.Pool, config *string, configErr bool) {
 			_, err := db.Exec(context.Background(), "CALL _prom_catalog.execute_maintenance_job(2, $1)", config)
 			if err != nil {
 				if !configErr {
@@ -1634,13 +1638,18 @@ func TestExecuteMaintJob(t *testing.T) {
 
 		}
 
-		execJob(nil, false)
+		execJob(dbOwner, nil, false)
 		config := `{"log_verbose": true}`
-		execJob(&config, false)
+		execJob(dbOwner, &config, false)
 		config = `{"log_verbose": false}`
-		execJob(&config, false)
+		execJob(dbOwner, &config, false)
 		config = `{"log_verbose": "rr"}`
-		execJob(&config, true)
+		execJob(dbOwner, &config, true)
+		config = `{"auto_explain": {"log_min_duration": 0, "log_nested_statements": "true"}}`
+		//dbOwner will not have enough permissions for auto_explain but this should still succeed
+		execJob(dbOwner, &config, false)
+		//the superuser should be able to use auto_explain
+		execJob(dbSuper, &config, false)
 	})
 }