Oracle SQL
  • LICENSE

Yearly Archives: 2022

CBO and Partial indexing

Posted on November 2, 2022 by Sayan Malakshinov Posted in bug, CBO, oracle, query optimizing, SQL, trace, troubleshooting 2,576 Page views Leave a comment

Oracle 12c introduced Partial indexing, which works well for simple partitioned tables with literals. However, it has several significant issues:

Continue reading→
cbo oracle partial indexes partial indexing query optimization troubleshooting undocumented oracle

Slow index access “COL=:N” where :N is NULL

Posted on October 31, 2022 by Sayan Malakshinov Posted in CBO, curious, Funny, oracle, query optimizing, SQL, troubleshooting 2,386 Page views Leave a comment

All Oracle specialists know that a predicate X=NULL can never be true and we should use “X is NULL” in such cases. The Oracle optimizer knows about that, so if we create a table like this:

Continue reading→
cbo oracle query optimization troubleshooting
photo Sayan Malakshinov

Oracle ACE Pro Oracle ACE Pro Alumni

DEVVYOracle Database Developer Choice Award winner

Oracle performance tuning expert

UK / Cambridge

LinkedIn   Twitter
sayan@orasql.org

Recent Posts

  • Oracle Telegram Bot
  • Partition Pruning and Global Indexes
  • Interval Search: Part 4. Dynamic Range Segmentation – interval quantization
  • Interval Search Series: Simplified, Advanced, and Custom Solutions
  • Interval Search: Part 3. Dynamic Range Segmentation – Custom Domain Index

Popular posts

Recent Comments

  • Oracle SQL | Interval Search: Part 4. Dynamic Range Segmentation – interval quantization on Interval Search: Part 3. Dynamic Range Segmentation – Custom Domain Index
  • Oracle SQL | Interval Search: Part 4. Dynamic Range Segmentation – interval quantization on Interval Search: Part 2. Dynamic Range Segmentation – Simplified
  • Oracle SQL | Interval Search: Part 4. Dynamic Range Segmentation – interval quantization on Interval Search: Optimizing Date Range Queries – Part 1
  • Oracle SQL | Interval Search Series: Simplified, Advanced, and Custom Solutions on Interval Search: Part 2. Dynamic Range Segmentation – Simplified
  • Oracle SQL | Interval Search: Part 2. Dynamic Range Segmentation – Simplified on Interval Search: Part 3. Dynamic Range Segmentation – Custom Domain Index

Blogroll

  • Alex Fatkulin
  • Alexander Anokhin
  • Andrey Nikolaev
  • Charles Hooper
  • Christian Antognini
  • Coskan Gundogar
  • David Fitzjarrell
  • Igor Usoltsev
  • Jonathan Lewis
  • Karl Arao
  • Mark Bobak
  • Martin Bach
  • Martin Berger
  • Neil Chandler
  • Randolf Geist
  • Richard Foote
  • Riyaj Shamsudeen
  • Tanel Poder
  • Timur Akhmadeev
  • Valentin Nikotin
©Sayan Malakshinov. Oracle SQL