Re: serial direct reads

Real-life example:
11.2.0.3 on AIX
DB_CACHE_SIZE = 4GB, DB_BLOCK_SIZE = 8K, so DB_CACHE_SIZE = 524,288 blocks 10% of DB_CACHE_SIZE = 52,429 blocks
_SMALL_TABLE_THRESHOLD = 10,257.

Table has DBA_TABLES.BLOCKS = 12,232
_DIRECT_READ_DECISION_STATISTICS_DRIVEN = TRUE
As table size is much smaller than 10% of DB_CACHE_SIZE one would expect that full table scan will be using buffered reads. However it is using direct reads (top wait event = 'direct path read'). Any idea why? Received on Thu Sep 04 2014 - 08:50:11 CEST