tag:blogger.com,1999:blog-14654018.post4360790574483802005..comments2023-07-18T12:55:13.959+01:00Comments on The /*+Go-Faster*/ Oracle Blog: Choosing the Right CompressionDavid Kurtzhttp://www.blogger.com/profile/00468908370233805717noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-14654018.post-43986891938187304042018-04-27T17:24:35.623+01:002018-04-27T17:24:35.623+01:00I have examined clustering by linear order in 12.1...I have examined clustering by linear order in 12.1.0.2. I ordered segments by columns frequently used in equality predicates, that have multiple distinct values, and that are not partitioning columns.<br />I found that clustering does improve the compression ratio of Hybridge Columnar Compressed objects, without apparently increasing the CPU overhead of decompression. There was no advantage for segments that were not compressed. However, caution is required because clustering it sorts the data. This can be a significant overhead on larger segments when the data is loaded. <br />In my tests, I only clustered smaller objects. I did see an improvement in query performance for only a small increase in load time. I did not test zone maps because I was not able to get them to work in conjunction with fast-refreshing materialized views in non-atomic mode.David Kurtzhttps://www.blogger.com/profile/00468908370233805717noreply@blogger.comtag:blogger.com,1999:blog-14654018.post-62472033689358187842018-04-20T08:44:28.140+01:002018-04-20T08:44:28.140+01:00Hello David
Vert informative thanks.
To complement...Hello David<br />Vert informative thanks.<br />To complement your post: <br />- HCC is also a ailable for all Enterprise Edition editions with the Oracle Database Cloud Service<br />- Did you try to increase the compression ratios using Clustering attributes and Zone Maps (would require Partitioning option) and this is available since 12.1.0.2<br /><br />Thanks<br />Loïc Lefèvrehttps://www.blogger.com/profile/03253006122037939972noreply@blogger.com