Bug 31495297 ORA-00600 [mal0-size-too-large] using huge number of union all

刘泽宇

Affects:

Product (Component)	Oracle Server (Rdbms)
Range of versions believed to be affected	Versions >= 12.2 but BELOW 23.1
Versions confirmed as being affected	19.8.0 19.1.0 12.2.0.1 (Base Release)
Platforms affected	Generic (all / most platforms affected)

Fixed:

The fix for 31495297 is first included in

(None Specified)

Interim patches may be available for earlier versions - click here to check.

Symptoms:	Related To:
Internal Error May Occur (ORA-600) ORA-600 [mal0-size-too-large]	(None Specified)

Description

ORA-600 [mal0-size-too-large] with expression monitoring of huge query.   REDISCOVERY INFORMATION: If a query with huge number of UNION ALL branches gets internal error ORA-600 [mal0-size-too-large] [qosdInitExprCtx: expoff_qosdExprCtx] and disabling expression monitoring prevents the error then you may have encountered this bug.    WORKAROUND: Disable expression monitoring via "_column_tracking_level". alter session set "_column_tracking_level" = 17;