ASSM
A couple of thoughts.The intent of ASSM is to minimise contention when multiple small transactions are busy inserting data concurrently into the same table. As a consequence, you may be able to find a...
View Articledbms_space usage
Just throwing out a brief comment (one of my many draft notes that I don’t have time to complete) about the dbms_space package. You’re probably familiar with this package and how, for ASSM segments, it...
View ArticleASSM Truncate.
Here’s one that started off with a tweet from Kevin Closson, heading towards a finish that shows some interesting effects when you truncate large objects that are using ASSM. To demonstrate the problem...
View ArticleLOB Space
Following on from a recent “check the space” posting, here’s another case of the code not reporting what you thought it would, prompted by a question on the OTN database forum about a huge space...
View ArticleClik here to view.
Why A Brand New Index Might Benefit From An Immediate Coalesce (One Slip)
A recent question on the OTN Forums Reg: Index – Gathering Statistics vs. Rebuild got me thinking on a scenario not unlike the one raised in the question where a newly populated index might immediately...
View ArticleASSM argh!
Here’s a problem with ASSM that used to exist in older versions of Oracle had disappeared by 11.2.0.4 and then re-appeared in 12.1.0.2 – disappearing again by 12.2.0.1. It showed up on MoS a few days...
View ArticleASSM Argh 2
After yesterday’s post one of the obvious follow-up questions was whether the problem I demonstrated was a side effect of my use of PL/SQL arrays and loops to load data. What would happen with a pure...
View ArticleASSM tangle
Here’s a follow-on from Tuesday’s (serious) note about a bug in 12.1.0.2 that introduces random slowdown on large-scale inserts. This threat in this note, while truthful and potentially a nuisance, is...
View ArticleRedo Dumps
A thread started on the Oracle-L list-server a few days ago asking for help analysing a problem where a simple “insert values()” (that handled millions of rows per day) was running very slowly. There...
View ArticleOracle 19c Automatic Indexing: Common Index Creation Trap (Rat Trap)
When I go to a customer site to resolve performance issues, one of the most common issues I encounter is in relation to inefficient SQL. And one of the most common causes for inefficient SQL I...
View Article