OEM 13c Reporting Incorrect Tablespace Space Usage (%) After July 2018 PSU

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, Enterprise Manager Cloud Control Tablespace Space Used (%) Metric Incorrectly Triggering (Doc ID 2313520.1)
DBA_TABLESPACE_USAGE_METRICS Returns Incorrect Information After applying (25397136) Bundle patch (Doc ID 2289448.1)
Thanks and happy patching,

2017 April PSU – OEM sending tablespace related alerts every collection schedule

I noticed that several alerts related to tablespace full were sent from OEM every collection schedule. At first sight I thought this may be related to OEM itself but after spending some significant time in MOS found a bug note stating that the 2017 April PSU patch was responsible.

The issue is that dba_tablespace_usage_metrics is not accounting for autoextend datafiles. So even if you add a new datafile, your used space will continue be reported as it was before.
You need to apply patch 26198757 on top of April PSU.
Hope this help you to avoid all this noise and happy patching.