Search Results for: SQL Profile

Using hints with coe_xfr_sql_profile.sql

In an earlier blog post I showed how I used coe_xfr_sql_profile.sql from the sqlt toolkit from Oracle support to force a particular sql statement to run with a more efficient plan that it had used in the past. Today, I’m … Continue reading

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Using coe_xfr_sql_profile.sql to force a good plan

Sunday night we worked with Oracle Support on a performance issue with a query that had been running for over 14 hours even though it ran the previous weekend in five minutes.  Oracle Support showed us how to use coe_xfr_sql_profile.sql … Continue reading

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Tweaked script to show top SQL by force matching signature

I just finished another production tuning exercise that is like two recent posts: Two New ASH FORCE_MATCHING_SIGNATURE scripts Tuning Example With Outline Hints and SQL Profile The biggest new thing was that I ran the ashtopelapsed.sql script that I mentioned … Continue reading

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AWR records top 30 SQLs by default

I forget that Oracle’s AWR only records the top 30 SQL statements in each snapshot by default. I am not sure how long this link will last but here is a 19c manual page describing the default: 19c manual – … Continue reading

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MySQL Source Installs for each RDS version

I have been doing a lot of Oracle and PeopleSoft work this year, but I am trying to continue to develop my MySQL and Amazon Web Services (AWS) knowledge at the same time. My goal is to learn some new … Continue reading

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One query in MySQL Performance Schema

I am learning about MySQL performance tuning. I read the Performance Schema chapter of the MySQL 5.7 manual and I have a MySQL 5.7.20 database running under Linux. I have a test table and I am running a simple query … Continue reading

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CPU Queue Time as SQL*Net wait

I was testing a script that did a lot of very short SQL statements and running many of them at the same time to bog down the CPU on the database server.  I kept seeing high “SQL*Net message from client” … Continue reading

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Session profile using V$ tables

Hopefully this is not too redundant to previous posts but I’ve found that I keep using a particular script to debug performance issues and I thought I’d share it and explain what I use it for.  It’s helpful to me … Continue reading

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SQLT Emergency Plan Change

I’m on call this week so I didn’t plan to do any blog posting but I had an interesting performance issue this morning that I thought would be helpful to document.  This is somewhat redundant to earlier posts but maybe … Continue reading

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Session profile using ASH

Worked on the scripts in this zip today: https://www.bobbydurrettdba.com/uploads/sessionprofiledbahist.zip I wanted to see a session profile from the DBA_HIST_ACTIVE_SESS_HISTORY view.  My idea was to include the time the session was inactive as well as the time it was waiting on an event or … Continue reading

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