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Pete Finnigan's Oracle Security Weblog

This is the weblog for Pete Finnigan. Pete works in the area of Oracle security and he specialises in auditing Oracle databases for security issues. This weblog is aimed squarely at those interested in the security of their Oracle databases.

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Another undocumented parameter in use (_ash_enable)

I saw a good post on the oracle-l list last week some time by Paul Drake that was titled "ASH droppings in bdump - / win32". Paul asked about the fact his Windows server running Oracle was generating hundreds of small trace files due to Active Session History (ASH). He said he is not using ASH and wanted to know how to turn off the trace file generation. The first response suggested that the old Oracle trace facility controlled by the parameter epc_disabled had gone and a new trace facility was now supplanted by a new trace controlled by a parameter called trace_enabled that if set to false will prevent trace file generation. John also supplied an interesting post to the thread that suggested using the hidden parameter _ash_enable to turn off Active Session History. John gave a useful piece of SQL that lists hidden parameters starting with _ash. Of course you should not usually use hidden parameters in production databases. But as usual I am interested in this post because of the undocumented element. Any use or confirmation of what an undocumented parameter does is always useful information in the security world. If during an audit you come across undocumented parameters being used its good to know potentially why.

Niall made a final post to the thread with an interesting answer that the only way to avoid the licensing issues in this case in a supported fashion is to set STATISTICS_LEVEL=BASIC as TYPICAL will enabled all the extra cost options.

Interesting thread!