How to Calculate pi
You can use the following series to calculate pi:4/1 - 4/3 + 4/5 - 4/7 + 4/9 - 4/11 + ...I decided to try this out using PL/SQL. The example I created is shown below. It works OK but the series...
View ArticleOnline Rebuild of Bitmap Indexes
I was reading an old Oracle 9 performance tuning book (as you do) and it said that you could not do online rebuilds of bitmap indexes.I did not have access to an Oracle 9 database so I tried it out in...
View ArticleORA-14306 and ORA-14400
Oracle apparently introduced list partitioning in Oracle 9. I decided to try it out in an Oracle 11 database.In this simple example I created a table to store the names of towns in Buckinghamshire,...
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How Auditors Might Be Cracking Your Oracle Passwords
I have often wondered how auditors crack Oracle passwords, particularly if the user concerned has a profile which locks the account after a few unsuccessful login attempts. I just realised today how...
View ArticleDeferred Segment Creation not Supported for Partitioned Tables in Oracle...
This post was sponsored by IMPERVAI tried to create a partitioned table with deferred segment creation in an Oracle 11.2.0.1 database.First I tried to do so explicitly but this did not work:SQL>...
View ArticleHow to Automatically Trace a User's Sessions
This post was sponsored by arcserve It shows how you can use a logon trigger to automatically trace all sessions for a given user. This can be useful where an application is launched from a desktop but...
View ArticleSUBSTR Versus LIKE in Oracle 11.2
I was reading an old SQL tuning book which was printed in 2002. It said that a where clause with like could often use an index whereas a similar clause using substr could not. I wondered if this might...
View ArticleMaking a Hot Backup and Doing an Incomplete Recovery
This post shows how to do a hot backup followed by an incomplete recovery. I ran it on an Oracle 11.2.0.4 test database. First I checked that the database was in ARCHIVELOG mode:SQL> select log_mode...
View ArticleMinor Problem with Resumable Session
Oracle started allowing sessions with space issues to hang rather than fail in version 9. I had always assumed this only worked if a tablespace ran out of space. However, I read recently that it also...
View ArticleOracle to Postgres Migration Issue with Commit
If you have some PL/SQL, Oracle allows you to include commit statements between a begin and end. Assuming this is appropriate for your application, it can produce two benefits:(1) If the code runs for...
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