2026-03-12 20:23:15

vdh/fsx.sql

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+----------------------------------------------------------------------------------------
+--
+-- File name:   fsx.sql
+--
+-- Purpose:     Find SQL and report whether it was Offloaded and % of I/O saved.
+--
+-- Author:      Kerry Osborne
+--
+-- Usage:       This scripts prompts for two values.
+--
+--              sql_text: a piece of a SQL statement like %select col1, col2 from skew%
+--
+--              sql_id: the sql_id of the statement if you know it (leave blank to ignore)
+--
+-- Description:
+--
+--              This script can be used to locate statements in the shared pool and 
+--              determine whether they have been executed via Smart Scans.
+--
+--              It is based on the observation that the IO_CELL_OFFLOAD_ELIGIBLE_BYTES
+--              column in V$SQL is only greater than 0 when a statement is executed
+--              using a Smart Scan. The IO_SAVED_% column attempts to show the ratio of
+--              of data received from the storage cells to the actual amount of data
+--              that would have had to be retrieved on non-Exadata storage. Note that 
+--              as of 11.2.0.2, there are issues calculating this value with some queries.
+--
+--              Note that the AVG_ETIME will not be acurate for parallel queries. The 
+--              ELAPSED_TIME column contains the sum of all parallel slaves. So the 
+--              script divides the value by the number of PX slaves used which gives an 
+--              approximation. 
+--
+--              Note also that if parallel slaves are spread across multiple nodes on
+--              a RAC database the PX_SERVERS_EXECUTIONS column will not be set.
+--
+--              See kerryosborne.oracle-guy.com for additional information.
+---------------------------------------------------------------------------------------
+set pagesize 999
+set lines 190
+col sql_text format a70 trunc
+col child format 99999
+col execs format 9,999
+col avg_etime format 99,999.99
+col "IO_SAVED_%" format 999.99
+col avg_px format 999
+col offload for a7
+
+select sql_id, child_number child, plan_hash_value plan_hash, executions execs, 
+(elapsed_time/1000000)/decode(nvl(executions,0),0,1,executions)/
+decode(px_servers_executions,0,1,px_servers_executions/decode(nvl(executions,0),0,1,executions)) avg_etime, 
+px_servers_executions/decode(nvl(executions,0),0,1,executions) avg_px,
+decode(IO_CELL_OFFLOAD_ELIGIBLE_BYTES,0,'No','Yes') Offload,
+decode(IO_CELL_OFFLOAD_ELIGIBLE_BYTES,0,0,100*(IO_CELL_OFFLOAD_ELIGIBLE_BYTES-IO_INTERCONNECT_BYTES)
+/decode(IO_CELL_OFFLOAD_ELIGIBLE_BYTES,0,1,IO_CELL_OFFLOAD_ELIGIBLE_BYTES)) "IO_SAVED_%",
+sql_text
+from v$sql s
+where upper(sql_text) like upper(nvl('&sql_text',sql_text))
+and sql_text not like 'BEGIN :sql_text := %'
+and sql_text not like '%IO_CELL_OFFLOAD_ELIGIBLE_BYTES%'
+and sql_id like nvl('&sql_id',sql_id)
+order by 1, 2, 3
+/