Statistics catalogue

This is a list of all articles I’ve written that talk about statistics, with a date stamp and short note of the contents. I have also created a couple of sub-catalogues around major topics:

• Column Groups catalogue
• Histograms catalogue
• Partition Stats catalogue (other authors 2007 – 2012)

I am currently working backwards through my entire blog adding articles to catalogues as I go, so any individual catalogue may grow very slowly.

• 19c – better stats (April 2022): Oracle now uses approx_count_distinct() on the whole index in dbms_stats.gather_index_stats().
• system_stats() hint (Jan 2022): notes on a hint that allows you to set the “noworkload” system statistics in a hint on Exadata.
• Optimizer Tip (Sept 2021): reprint of a note for IOUG 2015 on column groups and the table_cached_blocks preference
• Stats preferences (Aug 2021): a simple query to report all the system and table preferences, default or explicitly set
• Using the num_index_keys() hint (Nov 2018): controlling the split between access and filter predicates used in the index for complex in-lists.
• Reporting times of stats operations (Sept 2018): dbms_stats functions to report details of stats gathering operations.
  • Older version of stats timing code (Sept 2016): relevant for versions without dba_operation_opstat_tasks.
  • Pre-12c stats timing code (Sept 2016): hack code to get an indication of time spent on a table gathering it stats.
• Minimum Stats (Sept 2012): auto_sample_size on an index tends to mean 1,140 blocks

Other Authors

• Partition Stats (2007 – 2012) – a list of articles written by other people on the topic of staitistics on partitioned objects.
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