Skip to main content

Oracle Top segments

I use the following query to display the top 20 hot segments which have the biggest logical reads today.

query:
with hotsegmentvw as
(
select * from
(
SELECT obj# obj_id ,dataobj# data_obj_id,
     sum(logical_reads_delta) AS total_logical_reads
FROM dba_hist_seg_stat a
WHERE     a.snap_id in (select snap_id from dba_hist_snapshot  where trunc(BEGIN_INTERVAL_TIME)=trunc(sysdate))
GROUP BY obj#,dataobj#
order by sum(logical_reads_delta) desc
)
where rownum <= 20
)

select owner,object_name, total_logical_reads from hotsegmentvw a,dba_objects b
where a.obj_id = b.object_id
     AND a.data_obj_id = b.data_object_id
order by total_logical_reads
/

sample result:

OWNER           OBJECT_NAME                    TOTAL_LOGICAL_READS
--------------- ------------------------------ -------------------
ODYSSEY         SPOT_CHANNEL_I4                          334938608
ODYSSEY         SCHEDULE_AVAIL                           369947968
BSS             VERSION_U1                               380481744
BSS             TABLE_LINE_PK                            420110048
BSS             SCHEDULE_ITEM_I11                        424232128
ODYSSEY         SPOT_CHANNEL                             434493104
IBMSTASK        TASK_SERVER_LOG_I1                       440787200
ODYSSEY         IMPRESSION_COPY_PK                       467589344
ODYSSEY         SPOT_CHANNEL_U3                          561695824
BSS             TABLE_LINE                               618886448
ODYSSEY         SCHEDULE_SECTION_PK                      630677792
ODYSSEY         SCHEDULE_AVAIL_PK                        633438400
ODYSSEY         SALES_PRODUCT_DAYPART                    650545904
BSS             SCHEDULE_ITEM_PK                         671033824
ODYSSEY         SPOT                                     709647104
ODYSSEY         SCHEDULE_EVENT                           841863248
ODYSSEY         SALES_PRODUCT_DAYPART_PK                 993979440
ODYSSEY         SCHEDULE_EVENT_PK                       1319646848
BISTAGE         TMP_SPOT_GOUPING_I1                     3438150208
ODYSSEY         SPOT_PK                                 4701989600

Comments

Popular posts from this blog

Opatch apply/lsinventory error: oneoff is corrupted or does not exist

I am applying the quarterly patch for 19c RDBMS, I tried using napply but failed, but somehow it corrupted the inventory though nothing applied. further apply and lsinventory command ran into error like this: $ ./OPatch/opatch lsinventory Oracle Interim Patch Installer version 12.2.0.1.21 Copyright (c) 2020, Oracle Corporation.  All rights reserved. Oracle Home       : /u02/app/oracle/19.0.0 Central Inventory : /u01/app/oraInventory    from           : /u02/app/oracle/19.0.0/oraInst.loc OPatch version    : 12.2.0.1.21 OUI version       : 12.2.0.7.0 Log file location : /u02/app/oracle/19.0.0/cfgtoollogs/opatch/opatch2020-09-08_13-35-59PM_1.log Lsinventory Output file location : /u02/app/oracle/19.0.0/cfgtoollogs/opatch/lsinv/lsinventory2020-09-08_13-35-59PM.txt -------------------------------------------------------------------------------- Inventory load failed... OPatch cannot load inventory ...

oracle dba_hist_sysmetric_summary

found this blog is helpful to get CPU and IO statistics on oracle database. http://shob-dbadmin.blogspot.ca/2012/12/how-to-find-total-io-of-database.html courtesy to  Shomil Bansal , below are hist writing, not mine. How to find total IO of the database instance Total IO of database instance is sum of the physical reads, physical writes and redo writes. There are several views to find these values. v$sysmetric  - Reports metric values for only the most current time sample 60 secs. v$sysmetric_summary  - Reports metric values for time sample of 1 hour. v$sysmetric_history  - Reports metric values every 60 sec from the time instance is up. Better way to analyse IO using this view to take deltas between two time periods. dba_hist_sysmetric_history  - All the above views are refreshed when the instance is restarted. This view, part of AWR, stores the historical stats. I have used this view for my report. Query: ====== set lines 350...

ORA_RMAN_SGA_TARGET

assume that we lost all the files of oracle database but we do have rman backup, when trying to bring up a dummy database before restore start, I get this error. RMAN> startup nomount force; WARNING: cannot translate ORA_RMAN_SGA_TARGET value startup failed: ORA-01078: failure in processing system parameters ORA-01565: error in identifying file '+DATA/PROD/spfilePROD.ora' ORA-17503: ksfdopn:2 Failed to open file +DATA/PROD/spfilePROD.ora ORA-15056: additional error message ORA-17503: ksfdopn:DGOpenFile05 Failed to open file +DATA/prod/spfileprod.ora ORA-17503: ksfdopn:2 Failed to open file +DATA/prod/spfileprod.ora ORA-15173: entry 'spfileprod.ora' does not exist in directory 'prod' ORA-06512: at line 4 starting Oracle instance without parameter file for retrival of spfile RMAN-00571: =========================================================== RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS =============== RMAN-00571: =================================...