You can use the V$SQL.IS_RESOLVED_ADAPTIVE_PLAN column to know whether the execution plan associated to a child cursor is adaptive or not. Specifically, to know whether the query optimizer selected either an adaptive join method or an adaptive star transformation (notice that it is not set when the hybrid hash distribution is involved). The column takes […]
Offline Analysis of ASH Data with ASHDUMP
From time to time, it happens to me to carry out offline analyses of ASH data. For that, I mean to analyze the ASH data without having access to the database instance that generated it. For that purpose, Oracle Database provides the possibility to dump the content of the ASH buffer as well as information […]
Adaptive Plans in Active Session History
Yesterday, during the talk “The Query Optimizer in Oracle Database 12c – What’s New?” at OakTable World UK 2013, an attendee asked me an interesting question that can be summarized as follows: does ASH show the switch of execution plan that takes place for an adaptive plan? Since I didn’t know the answer, here are […]