There’s a very useful posting from Coskan Gundogar about tracking down a problem to do with an 11g upgrade.
The method basically revolves around a quick check for “known issues” that might be relevant by looking at the dynamic performance views v$system_fix_control.
When I read Coskan’s notes I had forgotten that I had written a short item about this myself about a year ago where I listed the relatively small number of items available in 10.2.0.3. The list is up to 1070 items in 12.1.0.2.
[…] and fixes to the optimizer that take place I decided to take a look at recent developments in the “fix control” list, and the “optimizer environment” parameters. Here’s a breakdown of the […]
Pingback by Upgrades « Oracle Scratchpad — February 20, 2012 @ 5:53 pm GMT Feb 20,2012 |
[…] code has been back-ported to 10.2.0.4 (and 10.2.0.5) but requires you to set a value for the hidden _fix_control parameter (which you can do at the session or system level) to enable the feature. There are three […]
Pingback by Index Upgrades « Oracle Scratchpad — March 9, 2012 @ 6:06 pm GMT Mar 9,2012 |
[…] that’s reported as fixed in 12c, with a couple of patches for 11.2.0.2/3. However, setting “_fix_control”=’4887636:off’, does bypass the problem. (The fix control, introduced in 11.1.0.6 has […]
Pingback by first_rows(10) | Oracle Scratchpad — October 31, 2014 @ 5:32 pm GMT Oct 31,2014 |
[…] as they upgrade to a newer version of Oracle. The change occurred at 11.2.0.2 as revealed by fix control 9303766 which has the description: “use 1/NDV+1/NROWS for col1 LIKE col2 […]
Pingback by Cardinality Change | Oracle Scratchpad — December 8, 2014 @ 9:35 pm GMT Dec 8,2014 |