This is yet another blogpost on Oracle’s direct path read feature which was introduced for non-parallel query processes in Oracle version 11. For full table scans, a direct path read is done (according to my tests and current knowledge) when: – The segment is bigger than 5 * _small_table_threshold. – Less than 50% of the …
When an Oracle process starts executing a query and needs to do a full segment scan, it needs to make a decision if it’s going to use ‘blockmode’, which is the normal way of working on non-Exadata Oracle databases, where blocks are read from disk and processed by the Oracle foreground process, either “cached” (read …
This is just a very small post on how to watch the progress of the “CopyBack” state of a freshly inserted disk in an Exadata “Computing” (database) node. A disk failed in the (LSI Hardware) RAID5 set, and the hotspare disk was automatically used. The failed disk was replaced, and we are now awaiting the …
For those of you who haven’t followed all the Oracle Exadata and database machine information, and want a brief introduction to the database machine: here it is! The confusion There is some confusion about ‘exadata’ and ‘the database machine’. If we look at the official product names, ‘Exadata’ is the storage server, and the ‘Database [...]