Tag Archives: oracle

How to make partition elimination/pruning to work

The blog was moved to: http://www.avmconsulting.net/single-post/2016/11/19/How-to-make-partition-eliminationpruning-to-work Check us out on http://avmconsulting.net Advertisements

Posted in Oracle | Tagged , , , , , | Leave a comment

Roll forward oracle database restored from storage snapshot

Most people use storage snapshots with Oracle DB these days. Its easy to restore DB to discrete point of time, i.e. to snapshots time. Here is a method of rolling forward the DB to any needed point of time using … Continue reading

Posted in Oracle, Systems | Tagged , , , , , , , , , , , , , | Leave a comment

Lost control file, So what?

Recently got involved in couple conversations regarding common “RULE OF THUMB” about backing up control file, and double backup of control file backup etc.. I guess its good thing to do, its does not take much space anyway, but if … Continue reading

Posted in Oracle, SQL | Tagged , , , , , , , | 2 Comments

High CPU usage on DB host?

Its Unix 101 statement, but I have heard it wrong so many time, so decided to put a blog for it. So: If in OLTP environment, per ‘top’ %wa (IOWAIT) is major contributor for CPU busy, adding CPU would not … Continue reading

Posted in Linux, Oracle, Systems, Uncategorized | Tagged , , , , , , , , , , , | Leave a comment

Top-N query

Term of “TOP-N” intuitively makes thinking what they query should run faster than just ORDERED query, as only N elements needed from it. But, as well known, not always.. This blog describes method how using proper index would optimize TOP-N  … Continue reading

Posted in SQL | Tagged , , , | Leave a comment

Index Clustering factor. One way how to avoid negative performance impact on joins which involves bad clustered indexes.

High Index Clustering factor is popular problem in SQL world. The most known solution for it – rebuild table ordering by columns what are in the index. But in real world, with table size growing exponentially its not always practical … Continue reading

Posted in SQL | Tagged , , , , | 2 Comments