[-] fix FREEZE age for partitioned tables in table_stats, fixes #760 (#783)

Author: pashagolub

pgwatch2/metrics/table_stats/10/metric.sql

@@ -48,7 +48,7 @@ with recursive /* pgwatch2_generated */
                autovacuum_count,
                analyze_count,
                autoanalyze_count,
-               age(c.relfrozenxid) as tx_freeze_age
+               case when c.relkind != 'p' then age(c.relfrozenxid) else 0 end as tx_freeze_age
         from pg_stat_user_tables ut
             join pg_class c on c.oid = ut.relid
             left join pg_class t on t.oid = c.reltoastrelid

pgwatch2/metrics/table_stats/16/metric.sql

@@ -48,7 +48,7 @@ with recursive /* pgwatch2_generated */
                autovacuum_count,
                analyze_count,
                autoanalyze_count,
-               age(c.relfrozenxid) as tx_freeze_age,
+               case when c.relkind != 'p' then age(c.relfrozenxid) else 0 end as tx_freeze_age,
                extract(epoch from now() - last_seq_scan)::int8 as last_seq_scan_s
         from pg_stat_user_tables ut
             join pg_class c on c.oid = ut.relid

pgwatch2/sql/config_store/metric_definitions.sql

@@ -2304,7 +2304,7 @@ with recursive /* pgwatch2_generated */
                autovacuum_count,
                analyze_count,
                autoanalyze_count,
-               age(c.relfrozenxid) as tx_freeze_age
+               case when c.relkind != 'p' then age(c.relfrozenxid) else 0 end as tx_freeze_age
         from pg_stat_user_tables ut
             join pg_class c on c.oid = ut.relid
             left join pg_class t on t.oid = c.reltoastrelid
@@ -2451,7 +2451,7 @@ with recursive /* pgwatch2_generated */
                autovacuum_count,
                analyze_count,
                autoanalyze_count,
-               age(c.relfrozenxid) as tx_freeze_age,
+               case when c.relkind != 'p' then age(c.relfrozenxid) else 0 end as tx_freeze_age,
                extract(epoch from now() - last_seq_scan)::int8 as last_seq_scan_s
         from pg_stat_user_tables ut
             join pg_class c on c.oid = ut.relid