Unusually High Value In V$UNDOSTAT.MAXQUERYLEN For Short Recursive SQL Statements
(Doc ID 2776001.1)
Last updated on MAY 16, 2021
Applies to:Oracle Database - Enterprise Edition - Version 184.108.40.206.0 and later
Oracle Database - Standard Edition - Version 220.127.116.11.0 and later
Information in this document applies to any platform.
Recursive SQL statements which should have completed in very short time appears as having high MAXQUERYLEN in V$UNDOSTAT.
Few examples of such recursive statements may include:
select /*+ no_parallel */ spare4 from sys.optstat_hist_control$ where sname=:1
select ts# from ts$ where ts$.online$ != 3 and bitand(flags,2048) != 2048
select 1 from sys.aq$_subscriber_table where rownum < 2 and subscriber_id <> 0 and table_objno <> 0
Another symptom may be that these statements show up in V$OPEN_CURSOR for a long time.
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