The topic for today is Tablespace monitoring. OEM 13c started reporting inaccurate values for the Space Usage (%) metric after applying either the April 2018 or the July 2018 Database PSU's. The way this was detected, is that OEM 13c Corrective Actions started firing here and there after the patches.
Oracle confirmed this is tracked on BUG 26198757.
This patch is available on top of both the April 2018 and the October 2018 PSU's but is not available for October 2018 PSU. The issue could also manifest itself as huge wait times on "Sync ASM rebalance" event.
Looks like the issue is corrected after applying the patch on top of July 2018 PSU. Below are some MOS realted to this.
Bug 26198757 - dba_tablespace_usage_metrics.used_percent is incorrect after applying 25397136 (Doc ID 26198757.8)
EM13c Space Monitoring Query (sqlid=69p6my4hpdm3j) On dba_tablespace_usage_metrics Timed Out after Db Upgraded To 12.2 (Doc ID 2375714.1)
EM 13c, 126.96.36.199: Enterprise Manager Cloud Control Tablespace Space Used (%) Metric Incorrectly Triggering (Doc ID 2313520.1)
DBA_TABLESPACE_USAGE_METRICS Returns Incorrect Information After applying 188.8.131.52.170418 (25397136) Bundle patch (Doc ID 2289448.1)
Thanks and happy patching,