So, my query plan says “Table Access Full” – what happens next?

22 Jan 2018
16:00 - 16:45

So, my query plan says “Table Access Full” – what happens next?

For some reports the fastest way to get them done is to use an index to go straight to the rows of interest, but sometimes the only way that makes sense is to scan the entire table. I’m the Oracle Architect for Smart Scan and the engineer in Oracle co-responsible for the table scan driver and this talk will show what happens under the covers in simple easy to understand steps. We will look at (1) what is a granule in PQ (2) how exactly does the system decided whether to use buffer cache to direct read, (3) how is physical I/O done including Multi-Block reads and Async-I/O (4) what wait events and stats to look at (5) what tuning options are available to the DBA, and (6) for the truly curious how to trace what is happening.