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Slow index access and COL=:N where :N is NULL
All Oracle specialists know that any predicate X=NULL can’t be true and we should use “X is NULL” in such cases. Oracle optimizer knows about that, so if we create a table like this: create table...
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CBO and Partial indexing
Oracle 12c introduced Partial indexing and sometimes it works fine for simple partitioned tables with literals, but it has a few serious problems: For example, consider the following simple...
View ArticlePartitioning by node (instance_number)
Years ago, I had to solve the problem of cluster-wide contention for log table blocks during a massive number of inserts from numerous sessions.Since the table was essentially insert-only and reads...
View ArticleInterval Search: Optimizing Date Range Queries – Part 1
One of the most common and enduring challenges in database management is performing efficient interval searches, particularly for date intervals such as: WHERE :dt BETWEEN beg_date AND end_date. In...
View ArticleInterval Search: Part 2. Dynamic Range Segmentation – Simplified
In the previous part, I discussed the most efficient known methods for optimizing range queries. In this part, I’ll introduce a simple version of my custom approach, which I call Dynamic Range...
View ArticleInterval Search: Part 3. Dynamic Range Segmentation – Custom Domain Index
In this part, I’ll show how to implement Dynamic Range Segmentation (DRS) explained in the previous part using a custom Domain Index, allowing you to apply this optimization with minimal changes to...
View ArticleInterval Search Series: Simplified, Advanced, and Custom Solutions
Interval Search: Part 1. Optimizing Date Range Queries Interval Search: Part 2. Dynamic Range Segmentation – Simplified Interval Search: Part 3. Dynamic Range Segmentation – Custom Domain Index
View ArticleInterval Search: Part 4. Dynamic Range Segmentation – interval quantization
Forums, mailing lists, and StackOverflow are all great resources for Oracle performance discussions, but I’ve long thought it would be useful to have a dedicated online chat/group specifically for...
View ArticlePartition Pruning and Global Indexes
There is a common misconception that partition pruning does not help in the case of global indexes and only works with local indexes or full table scans (FTS). It is understandable how this...
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Oracle Telegram Bot
For the Oracle performance tuning and troubleshooting Telegram channel https://t.me/ora_perf, I developed a simple helpful Telegram bot. It simplifies common Oracle database tasks directly within...
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