Skip to main content

oracle with clause and materialize hint

oracle guru Burleson's note  helped me to improve performance on a query cross database link
http://www.dba-oracle.com/t_with_clause.htm

 we have a database link from oracle to MS SQL server using oracle DRDA, the following query take long to complete, I cannot wait for it to complete and have to kill the query.

SELECT count(*) FROM "ContractItem"@QSENCT002 A, "contractheader_cr"@QSENCT002 B
WHERE A. "ContractHeaderID" = B. "contractheaderid"
AND "ContractItemDayID" BETWEEN 37345 AND 37346
and not exists
(SELECT REVENUESTREAMEXPORTID FROM radiostage.REVENUESTREAMEXPORT_XREF WHERE DIVESTED = 'Y' and A."RevenueStreamExportID" =REVENUESTREAMEXPORTID )
/

After re-write the query using with clause and materialize hint, the query complete in 1 second.
However, if I give bigger range of date in the query, the performance is not improved much, so it's depends on case by case.

with ctview as
(select /*+ materialize */ * FROM "ContractItem"@QSENCT002 A, "contractheader_cr"@QSENCT002 B
WHERE A. "ContractHeaderID" = B. "contractheaderid"
AND "ContractItemDayID" BETWEEN 37345 AND 37346)
select count(*) from ctview
where ctview."RevenueStreamExportID" NOT IN (SELECT REVENUESTREAMEXPORTID FROM radiostage.REVENUESTREAMEXPORT_XREF WHERE DIVESTED = 'Y')

/

  COUNT(*)
----------
         0

Elapsed: 00:00:00.88

Execution Plan
----------------------------------------------------------
Plan hash value: 1488614543

--------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                  | Name                        | Rows  | Bytes | Cost (%CPU)| Time  | Inst   |IN-OUT|
--------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT           |                             |     1 |    18 |   406   (1)| 00:00:05 |        |      |
|   1 |  TEMP TABLE TRANSFORMATION |                             |       |       |            |       |   |      |
|   2 |   LOAD AS SELECT           | SYS_TEMP_0FD9D6603_13638A70 |       |       |            |       |   |      |
|   3 |    REMOTE                  |                             |     5 |  1300 |   200   (0)| 00:00:03 | QSENC~ | R->S |
|   4 |   SORT AGGREGATE           |                             |     1 |    18 |            |       |   |      |
|*  5 |    HASH JOIN ANTI NA       |                             |     1 |    18 |     6  (17)| 00:00:01 |        |      |
|   6 |     VIEW                   |                             |     5 |    65 |     2   (0)| 00:00:01 |        |      |
|   7 |      TABLE ACCESS FULL     | SYS_TEMP_0FD9D6603_13638A70 |     5 |  1365 |     2   (0)| 00:00:01 |        |      |
|*  8 |     TABLE ACCESS FULL      | REVENUESTREAMEXPORT_XREF    |     4 |    20 |     3   (0)| 00:00:01 |        |      |
--------------------------------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   5 - access("CTVIEW"."RevenueStreamExportID"="REVENUESTREAMEXPORTID")
   8 - filter("DIVESTED"='Y')

Remote SQL Information (identified by operation id):
----------------------------------------------------

   3 - SELECT A1."ContractItemID",A1."ContractHeaderID",A1."RevenueStreamExportID",A1."ContractItemDayID",A1."DayP
       artHalfHourID",A1."TransactionDayID",A1."ContractItemStatusID",A1."ContractItemTypeID",A1."SaleTypeID",A1."Industr
       yProductID",A1."TransactionCodeID",A1."AnnouncementTypeID",A1."NumberOfItems",A1."TotalCostGross",A1."TotalCostNet
       ",A1."TotalValueGross",A1."TotalValueNet",A1."IsBroadcast",A1."SpotLengthID",A1."CustomerID",A2."contractheaderid"
        FROM "ContractItem" A1,"contractheader_cr" A2 WHERE A1."ContractHeaderID"=A2."contractheaderid" AND
       A1."ContractItemDayID">=37345 AND A1."ContractItemDayID"<=37346 (accessing 'QSENCT002' )



Statistics
----------------------------------------------------------
        205  recursive calls
          7  db block gets
        217  consistent gets
          9  physical reads
       1392  redo size
        209  bytes sent via SQL*Net to client
        252  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          5  sorts (memory)
          0  sorts (disk)
          1  rows processed


11:26:12 RMS8DEV>

Comments

Post a Comment

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 ...
Post a Comment
Read more

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...
Post a Comment
Read more

non-existent process lock port on windows server

I have a database link created between oracle and sqlserver using oracle tg4odbc, the product is installed on windows server and run as service "OracleOraGtw11g_home1TNSListener", but sometime the service cannot started, the root cause of this problem is that the port number 1521 is used by an non-existent process. The first step is to use netstat -bano|find "1521" to get the process id, in my case it's 5844, which shows the connection is from my oracle server 10.8.0.169 H:\>netstat -bano|find "1521"   TCP    0.0.0.0:1521           0.0.0.0:0              LISTENING       5844   TCP    10.14.45.33:1521       10.8.0.169:42987       ESTABLISHED     5844 however the process id does not show in either task manager or process explorer. The next step is to run tcpview, which shows non-existent under process column, there are three rows, t...
3 comments
Read more