Hi all,
Three Performance-related points in this thread:
1. Index Compression:
I have read in several threads and in the SAP note 1436352 - Oracle Database 11g Advanced Compression for SAP Systems than the indexes should compressed before than the table.
My question is, can this impact in the performance after compression?
I mean, if I follow this sequence would I have any performance problem:
- Table Online Reorg with brSpace and option -c ctab:
brspace -u / -f tbreorg -o <Owner> -t <Table> -c ctab -p 4
- Index Rebuild with brSpace and option -c cind:
brspace -u / -c force -f idrebuild -o <Owner> -i <Index> -c cind -p 4
2. Number of columns:
I noticed that there is a limitation of 255 columns in the OLTP compression, but my question is if the number of columns could negatively impact in performance accessing compressed tables (Read Operations). In my case the table has 225 columns.
3. Poor performance in Read Operations:
I have compressed a serveral GL tables in our test environment and the times for the same SELECT sentence is around 30% slower after compression. The compression ratio was very good.
As you can imagine, we have applied the compression following the point number 1 of this thread and the table has got 225 columns.
Is there any factor that can impact negatively in read operations in compression tables?
My Oracle version is 11.2.0.3.0 and SAP 7.01
Thanks in advance.