Performance

Matching SQL Plan Directives and extended stats

By Franck Pachot . This year is the year of migration to 12c. Each Oracle version had its CBO feature that make it challenging. The most famous was the bind variable peeking in 9iR2. Cardinality feedback in 11g also(…)

Variations on 1M insert (2): write commit

In this blog post, I will try to do the same than my colleagues about Oracle and for PostgreSQL. As a reminder, we’ve seen in my previous blog post that SQL Server is designed(…)

Variations on 1M rows insert(2): commit write

By Franck Pachot . In the previous blog post I measured the time it takes to insert 1 million rows. About 45 seconds when done row-by-row which goes down to 7 seconds when inserted in bulk. In both(…)

Variations on 1M rows insert (1): bulk insert

By Franck Pachot . This blog is the first one of a series about inserting 1 million rows. Do you have an idea about the time it takes? The idea came from another project, about NoSQL databases, but I’ll(…)

Oracle tuning silver bullet: add an order by to make your query faster

By Franck Pachot . You have read all Cary Millsap work about Oracle database performance tuning. You know that there are no silver bullets. Reducing the response time requires a methodical approach in order to analyze the response time(…)

A funny story with recompile hint at statement level

Last night, I had an interesting discussion with one of my MVP French friend that faces a weird situation where a query that uses a statement level RECOMPILE hint produces an execution plan that disappointed him. He told me we(…)

Analyzing easily the blocked process report

Which DBA has not yet face a performance problem issued by several blocked processes? In reality, I’m sure a very little number of them. Troubleshooting a blocked issue scenario is not always easy and may require to use some useful(…)

Generic query for multicriteria search – part II: BIND_AWARE (Adaptive Cursor Sharing)

By Franck Pachot . In the previous post I explained the performance issue encountered when using a generic query to deal with optional search criteria on multiple columns. The statement was shared by all executions, was marked as(…)

Never gather WORKLOAD stats on Exadata…

By Franck Pachot . For Exadata, oracle has introduced an ‘EXADATA’ mode which sets a high transfer rate (with IOTFRSPEED as in NOWORKLOAD statistics) and set a MBRC (as in WORKLOAD statistics). Those values are set rather than gathered(…)

IOUG Collaborate #C15LV

By Franck Pachot . The IOUG – Independant Oracle User Group – has a great event each year: the COLLABORATE. This year it’s in April 12-16, 2015 at The Mandalay Bay Resort & Casino in Las Vegas. I’ll be(…)