2026-03-12 20:23:15

tpt/ash/event_hist_cell.sql

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+-- Copyright 2018 Tanel Poder. All rights reserved. More info at http://tanelpoder.com
+-- Licensed under the Apache License, Version 2.0. See LICENSE.txt for terms & conditions.
+
+-- this script uses "ASH math" by John Beresniewicz, Graham Wood and Uri Shaft
+-- for estimating the event counts (and average durations):
+--   https://www.slideshare.net/jberesni/ash-architecture-and-advanced-usage-rmoug2014-36611678
+
+COL evh_event HEAD WAIT_EVENT for A50 TRUNCATE
+COL evh_graph HEAD "Estimated|Time Graph" JUST CENTER FOR A12
+COL pct_evt_time HEAD "% Event|Time"
+COL evh_est_total_sec HEAD "Estimated|Total Sec" FOR 9,999,999.9
+COL evh_millisec HEAD "Wait time|bucket ms+" FOR A15 JUST RIGHT
+COL evh_event HEAD "Wait Event"
+COL evh_sample_count HEAD "Num ASH|Samples"
+COL evh_est_event_count HEAD "Estimated|Total Waits"
+COL evh_cell_path HEAD "Cell Path" FOR A16
+
+BREAK ON evh_event SKIP 1 ON evh_cell_path SKIP 1 NODUPLICATES
+
+PROMPT Showing only CELL wait events as they have the wait_event.p1 = v$cell.cell_hashval link...
+
+SELECT
+    e.*
+  , ROUND ( 100 * RATIO_TO_REPORT(evh_est_total_sec) OVER (PARTITION BY evh_event) , 1 ) pct_evt_time
+  , '|'||RPAD(NVL(RPAD('#', ROUND (10 * RATIO_TO_REPORT(evh_est_total_sec) OVER (PARTITION BY evh_event)), '#'),' '), 10)||'|' evh_graph
+FROM (
+    SELECT 
+        event evh_event
+      , c.cell_path evh_cell_path
+      , LPAD('< ' || CASE WHEN time_waited = 0 THEN 0 ELSE CEIL(POWER(2,CEIL(LOG(2,time_waited/1000)))) END, 15) evh_millisec
+      , COUNT(*)  evh_sample_count
+      , ROUND(SUM(CASE WHEN time_waited >= 1000000 THEN 1 WHEN time_waited = 0 THEN 0 ELSE 1000000 / time_waited END),1) evh_est_event_count
+      , ROUND(CASE WHEN time_waited = 0 THEN 0 ELSE CEIL(POWER(2,CEIL(LOG(2,time_waited/1000)))) END * SUM(CASE WHEN time_waited >= 1000000 THEN 1 WHEN time_waited = 0 THEN 0 ELSE 1000000 / time_waited END) / 1000,1) evh_est_total_sec
+    FROM 
+        V$ACTIVE_SESSION_HISTORY a
+      , v$cell c
+        --dba_hist_active_sess_history
+    WHERE 
+        c.cell_hashval = a.p1
+    AND regexp_like(a.event, '&1') 
+    AND &2
+    AND a.sample_time BETWEEN &3 AND &4
+    AND a.session_state = 'WAITING' -- not really needed as "event" for ON CPU will be NULL in ASH, but added just for clarity
+    AND a.time_waited > 0 
+    GROUP BY
+        event
+      , c.cell_path
+      , CASE WHEN time_waited = 0 THEN 0 ELSE CEIL(POWER(2,CEIL(LOG(2,time_waited/1000)))) END -- evh_millisec
+) e
+ORDER BY
+    evh_event
+  , evh_cell_path
+  , evh_millisec
+/
+