November 2017

Buffer cache hit ratio–blast from the past

I was perusing some old content during a hard drive “spring clean” the other day, and I found an old gem from way back in 2001.  A time when the database community were trying to dispel the myth that all database performance issues could be tracked back to,  and solved via, the database buffer cache hit ratio.  Thankfully, much of that folklore has now passed into the realm of fiction, but I remember at the time, as a means of showing how silly some of the claims were, I published a routine that would generate any buffer cache hit ratio you desired.  It just simply ran a query to burn through logical I/O’s (and burn a whole in your CPU!) until the required number of operations bumped up the buffer cache hit ratio to whatever number you liked Smile 

nVision Performance Tuning: 6. Logging Selector Usage

This blog post is part of a series that discusses how to get optimal performance from PeopleSoft nVision reporting as used in General Ledger.

Static selectors are tracked by entries in the PSTREESELCTL table.  It is maintained after the tree is extracted to the selector table.  The version number on PSTREESELCTL is compared with the corresponding version number on the PSTREEDEFN to determine whether the extract of the tree to the selector table is still valid, or whether it needs to be reextracted because the tree has been updated.  Selectors that do not have an entry in PSTREESELCTL are therefore dynamic.

UKOUG is coming

Yes it is just a few more weeks until the UKOUG conference swings by.

This has been one of my favourite conferences for years – dating back to my first one in 2002 !!.  You can see from the picture at the tail of this post – whilst times have changed in those 15 years, the basic tenets of community, networking and technical content remain unchanged to this day.

The AskTOM team will all be there and there’s a fantastic agenda spread over 4 days.  This user group really knows how to “bake” a good conference.  Maybe they followed my recipe. Smile

 

Multitenant internals: INT$ and INT$INT$ views

This month, I’ll talk – with lot of demos – about multitenant internals at DOAG conference. CaptureMultitenantInternals

Multitenant dictionary: what is consolidated and what is not

The documentation says that for Reduction of duplication and Ease of database upgrade the Oracle-supplied objects such as data dictionary table definitions and PL/SQL packages are represented only in the root.

Unfortunately, this is only partly true. System PL/SQL packages are only in root but system table definition are replicated into all PDBs.

This post is an extension of a previous blog post which was on 12cR1. This one is on 12cR2.

IP CIDR rules and address ranges

I always forget IP address range coverage rules and forget where to look.

It’s the wiki!

https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing

and for good reference here is the table:

/32 is for a single address

/24 is for a range in the last place x.x.x.0

/16 is for a range in the last 2 places x.x.0.0

Screen Shot 2017-11-03 at 11.28.31 AM

Pass Summit 2017, 2nd Day, Thursday

Thursday started out calm, self-assured that I knew where I needed to be all day and was prepared.  I tweeted happily that I had found a lovely spot to work during the keynote, (day job!)

Yeah, this:

Quick history on database growth

AWR collects segment statistics, and this can be used to quickly understand an abnormal database growth. Here is a script I use to get, from the AWR history, the segments that have grown by more than 1% of the database size, in one hour.

First I must mention that this uses only the part of AWR which is not subject to additional option. This even works in Standard Edition:
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_management_pack_access string NONE

Pass Summit 2017, 1st Day, Also Known as HumpDay

I’ve plenty of rest after arriving in Seattle yesterday to get my registration for Pass Summit, attended the Women in Technology Happy Hour and then received my Idera ACE!

nVision Performance Tuning: 5. Additional Instrumentation of nVision

This blog post is part of a series that discusses how to get optimal performance from PeopleSoft nVision reporting as used in General Ledger.

One of the challenges of tuning and monitoring nVision is to be able to identify each report being run. Calls to Oracle instrumentation package dbms_application_info  were added to the component processor in PeopleTools 8.50, and to Application Engine in PeopleTools 8.52.  However, COBOL, nVision, and SQR were never instrumented.