A NULL result should be reported when a stats timestamp is set to 0, but
c037471 missed that, leading to a confusing timestamp value after for
example a DML on a freshly-created relation with no scans done on it
yet.
This impacted the following attributes for two system views:
- pg_stat_all_tables.last_idx_scan
- pg_stat_all_tables.last_seq_scan
- pg_stat_all_indexes.last_idx_scan
Reported-by: Robert Treat
Analyzed-by: Peter Eisentraut
Author: Dave Page
Discussion: https://postgr.es/m/CABV9wwPzMfSaz3EfKXXDxKmMprbxwF5r6WPuxqA=5mzRUqfTGg@mail.gmail.com
index 96bffc0f2aceb8a6b8ca03b493503a253d33f90e..ae3365d917155af4e9a3aa2a245150b92989055f 100644 (file)
pg_stat_get_lastscan(PG_FUNCTION_ARGS)
{
Oid relid = PG_GETARG_OID(0);
+ TimestampTz result;
PgStat_StatTabEntry *tabentry;
if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
+ result = 0;
+ else
+ result = tabentry->lastscan;
+
+ if (result == 0)
PG_RETURN_NULL();
else
- PG_RETURN_TIMESTAMPTZ(tabentry->lastscan);
+ PG_RETURN_TIMESTAMPTZ(result);
}
index 257a6a9da9a0cbaa391ac9038207b65bed8c6a06..1d84407a039da6791a0b8490d542f4823e32b2ee 100644 (file)
(1 row)
+SELECT last_seq_scan, last_idx_scan FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass;
+ last_seq_scan | last_idx_scan
+---------------+---------------
+ |
+(1 row)
+
COMMIT;
SELECT pg_stat_reset_single_table_counters('test_last_scan'::regclass);
pg_stat_reset_single_table_counters
index f6270f7badb760e880c2202498e8affac1e779c7..b4d6753c7103f62437776f6a341ee613b7258478 100644 (file)
CREATE TEMPORARY TABLE test_last_scan(idx_col int primary key, noidx_col int);
INSERT INTO test_last_scan(idx_col, noidx_col) VALUES(1, 1);
SELECT pg_stat_force_next_flush();
+SELECT last_seq_scan, last_idx_scan FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass;
COMMIT;
SELECT pg_stat_reset_single_table_counters('test_last_scan'::regclass);