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12.2 Online Conversion of a Non-Partitioned Table to a Partitioned Table (A...
In my previous post, I discussed how you can now move heap tables online with Oracle Database 12.2 and how this can be very beneficial in helping to address issues with the Clustering Factor of key...
View ArticleImprove Data Clustering on Multiple Columns Concurrently (Two Suns in the...
I’ve had a couple of recent discussions around clustering and how if you attempt to improve the clustering of a table based on a column, you thereby ruin the current clustering that might exist for a...
View ArticleAnswer: Anything Wrong With Query Performance? (Red Right Hand)
I of course attract a highly clever readership :). As some have commented, for a single table to require 1000+ consistent gets to retrieve 1000 rows implies that each row needs to be accessed from a...
View ArticleRebuilding Indexes: Danger With Clustering Factor Calculation (Chilly Down)
Let me start by saying if you don’t already following Jonathan Lewis’s excellent Oracle blog, do yourself a favour. In a recent article, Jonathan highlighted a danger with rebuilding indexes (or indeed...
View ArticleOracle Database 19c Automatic Indexing: Default Index Column Order Part II...
In Part I, we explored some options that Oracle might adopt when ordering the columns within an Automatic Index by default, in the absence of other factors where there is only the one SQL statement to...
View ArticleOracle 19c Automatic Indexing: Mixing Manual and Automatic Indexes Part I (I...
In previous articles, I discussed how Automatic Indexing has the capability to add columns or reorder the column list of previously created Automatic Indexes. However, how does Automatic Indexing...
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 ArticleOracle 19c Automatic Indexing: Poor Data Clustering With Autonomous Databases...
I’ve discussed many times the importance of data clustering in relation to the efficiency of indexes. With respect to the efficiency of Automatic Indexes including their usage within Oracle’s...
View ArticleOracle 19c Automatic Indexing: Poor Data Clustering With Autonomous Databases...
In my previous post, I discussed a scenario in which Oracle Automatic Indexing refused to create a VALID index, because the resultant index was too inefficient to access the necessary rows due to the...
View ArticleOracle 19c Automatic Indexing: Poor Data Clustering With Autonomous Databases...
In Part I we looked at a scenario where an index was deemed to be too inefficient for Automatic Indexing to create a VALID index, because of the poor clustering of data within the table. In Part II we...
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