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Detail! And don’t forget the notes…

…and how sparse tables can mess up your dynamic sampling. A little lesson to self about paying attention to the detail, the obvious frickin’ detail. Getting older and slower. We had one of those problems where a multitude of things were slow and yet there were no significant system-level problems (e.g. no general slow IO, no setting of the fast=false parameter, etc) In such situations, if you check the high level system level...

Inline Hint

If you’ve ever used subquery factoring (“with” subqueries or common table expressions (CTEs) as they are often called) then you’re probably aware of the (undocumented) hints /*+ materialize */ , which forces Oracle to create a local temporary table to hold the result of the subquery for subsequent use, and /*+ inline */, which forces the optimizer to copy the text of the subquery into the body of the query before starting the...

Bloom Upgrade

It’s a common pattern of Oracle features that they start with various restrictions or limitations that disappear over time. This note is about an enhancement to Bloom filter processing that appeared in the 18.1 optimizer and, for some people, may be a good enough reason for upgrading to a newer version of Oracle. This enhancement came to my attention through a question on the Oracle Developer forum asking how to get a Bloom filter...