Oracle-L: Re: Refresh option for Materialized view , want to use it during refresh

From: David Boyd <davidb158_at_hotmail.com>
Date: Tue, 28 Oct 2003 09:04:25 -0800
Message-ID: <F001.005D4D18.20031028090425@fatcity.com>

Arup,

I really appreciate your answer in great details. I got "on prebuilt table" work. Thanks a lot for your help. Here is another question:

Do you see any advantage to use materialized view on prebuilt table for my data loading over just simple renaming tables as steps below:

create table t that is always accessed by applications
create table t1 that is a temp table for loading
load data into table t1
rename table t to table t2
rename table t1 to t
rename table t2 to t1
truncate table t1 for next day loading

David

>From: "Arup Nanda" <orarup_at_hotmail.com>
>Reply-To: ORACLE-L_at_fatcity.com
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: Re: Refresh option for Materialized view , want to use it during
>refresh - for
>Date: Fri, 24 Oct 2003 18:04:33 -0800
>
>David,
>
>Answers to your questions:
>
>(1) Without knowing your exact needs, I wil offer a few different
>scenarios.
>I am assuming that you are doing a complete refresh every time. The
>following pertain to that.
>
>Say, your name of the MV is MV1. Here are the steps the first time.
>
>1. Create table MV1
>2. Create MV MV1 on that table.
>
>When you want to refresh complete:
>
>1. Create table MV1_TEMP. Choose a suitable method: CTAS across dblink
>(with
>NOLOGGING), SQL*Loader, Direct Load Insert, or simpley exp/imp.
>2. Drop MV MV1. This drops the MV but doesn't drop the table.
>3. Drop table MV1.
>4. Rename table MV1_TEMP to MV1.
>5. Recreate MV MV1.
>6. Allow users to proceed as usual.
>
>Note the time consumed between Steps 2 and 6 are in the order of a few
>seconds. And it's the only time the users will not have access to the MV,
>as
>opposed to a full refresh using dbms_mview.refresh approach., which will
>lock the MV for the entire duration and generate tons of redo and rollback.
>
>Even if you do a incremental refresh, this is still a better approach. In
>that case, you don't drop the table during the refresh.
>
>(2) Yes, the option is available in 8i, at least in 8.1.7. Make sure the
>syntax is correct.
>
>create materialized view MV1
>on prebuilt table
>refresh fast
>as
>select ... from ....
>
>In the article I mentioned, you can find the complete syntax.
>www.proligence.com/downloads.html is the site. It also dscribes a step by
>step solution to the issue and compares the common solution with this new
>one.
>
>Hope this helps.
>
>Arup Nanda
>
>----- Original Message -----
>To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
>Sent: Friday, October 24, 2003 12:34 PM
>refresh - for
>
>
> > Hi Arup,
> >
> > This is a very good method. I would like to use it to modify some of my
> > data loading procedures. Here are my questions:
> > 1. Do I need to create the table on the step 1 every time when I refresh
>the
> > data If I refresh data once per day?
> > 2. Is "ON PREBUILT TABLE" available on Oracle 8i? When I was trying the
> > method on Oracle 8i, I got missing keyword error on "PREBUILT".
> >
> > Dave
> >
> > >
> > >Siddharth,
> > >
> > >I will offer a slightly out-of-the-box solution. Please read it through
> > >till the end to determine its applicability in your case.
> > >
> > >It seems yours refresh interval is once a day and you don't mind stale
> > >data for a max of 24 hours. You also refresh is complete, not
> > >incremental. So, I would suggest the follwoing approach.
> > >
> > >(1) Create a table first
> > >CREATE TABLE CT_PRODUCTID_VW
> > >TABLESPACE ....
> > >NOLOGGING
> > >AS
> > >SELECT .....
> > >
> > >(2) When you are ready to "refresh", drop the MV
> > >DROP MATERIALIZED VIEW CT_PRODUCTID_VW;
> > >
> > >(3) Create the MV with the PREBUILT TABLE option.
> > >CREATE
> > >MATERIALIZED VIEW CT_PRODUCTID_VW
> > >BUILD IMMEDIATE
> > >REFRESH START WITH SYSDATE
> > >NEXT (SYSDATE + 1)
> > >ON PREBUILT TABLE
> > >AS
> > >SELECT
> > > msi.segment1 productid,
> > >...
> > >
> > >Your MV is not accessible between STEP 2 and STEP3, which is really a
> > >dictionary update and takes about a second or so. So the "outage" is
> > >really 1 second, not 1/2 hr.
> > >
> > >A few explanations are in order here.
> > >
> > >(1) Creating an MV on a Prebuilt Table does not consume more space. The
> > >segment that used to be a table simply becomes an MV.
> > >(2) When you drop the MV, the MV is gone, but the table remains
>instact.
> > >(3) The table can be create by any means - export/import, SQL*Loader,
> > >INSERT APPEND, etc.
> > >(4) IT places less strain on the system comapred to the MV refresh
> > >option, simply because the MV refresh truncates the segment and then
> > >builds it.
> > >
> > >I presented a paper to the same effect at IOUG Live 2003. You can
> > >download a modified version of the same from my website
> > >www.proligence.com/downlaods.html, titled "Painless Master Table Alter"
> > >from the Presentations Section.
> > >
> > >HTH.
> > >
> > >Arup Nanda
> > >
> > >
> > >
> > >
> > >
> > >----- Original Message -----
> > >To: Multiple recipients of list ORACLE-L
> > >Sent: Tuesday, October 21, 2003 3:59 AM
> > >refresh
> > >
> > >
> > >Hi Gurus,
> > >
> > >I have a materialized view, which is based on Oracle Apps tables and on
> > >remote database. The view refresh takes around ½ hour, during this time
> > >period I cannot see any records in the materialized view and therefore
> > >my application faces errors.
> > >The following is the view definition
> > >
> > >CREATE
> > >MATERIALIZED VIEW CT_PRODUCTID_VW
> > >BUILD IMMEDIATE
> > >REFRESH START WITH SYSDATE
> > >NEXT (SYSDATE + 1)
> > >AS
> > >SELECT
> > > msi.segment1 productid,
> > > msi.description description,
> > > msi.inventory_item_id inventory_item_id,
> > > mc.segment1 product_family,
> > > mc.segment2 product_type
> > >FROM MTL_CATEGORY_SETS_at_CME_ODSPROD mcs,
> > > MTL_CATEGORIES_at_CME_ODSPROD mc,
> > > MTL_ITEM_CATEGORIES_at_CME_ODSPROD mic,
> > > MTL_SYSTEM_ITEMS_at_CME_ODSPROD msi
> > >where 1=1
> > >and mc.structure_id = 50112
> > >and mc.segment3 != 'SPARE'
> > >and mc.global_name = 'US'
> > >and mc.enabled_flag = 'Y'
> > >and mcs.global_name = mc.global_name
> > >and mcs.category_set_name = 'PROD GROUP'
> > >and mic.category_set_id = mcs.category_set_id
> > >and mic.category_id = mc.category_id
> > >and mic.global_name = mc.global_name
> > >and mic.organization_id = 1
> > >and mic.inventory_item_id = msi.inventory_item_id
> > >and msi.organization_id = mic.organization_id
> > >and msi.global_name = mc.global_name
> > >AND msi.auto_created_config_flag = 'N'
> > >AND msi.item_type IN ('ATO MODEL','CONFIG SPARE','CONFIG
> > >SUB','FEATURE PACK','PRODUCT LIST>$0','PTO MODEL','SPARE')
> > >and msi.inventory_item_status_code IN
> > >('ENABLE-MAJ','ENABLE-NON','ENABLE-OPT','NONORD')
> > >
> > >Please note that the tables referenced are remote tables and Oracle
>Apps
> > >tables and not logging on it is possible.
> > >Please suggest an appropriate refresh mechanism to see the records even
> > >during refresh period.
> > >
> > >Thanks in advance.
> > >
> > >With Warm Regards
> > >
> > >
> > >
> > >Siddharth Haldankar
> > >Zensar Technologies Ltd.
> > >Cisco Systems Inc.
> > >(Offshore Development Center)
> > ># : 091 020 4128394
> > >shaldank_at_cisco.com
> > >s.haldankar_at_zensar.com
> > >
> >
> > _________________________________________________________________
> > Cheer a special someone with a fun Halloween eCard from American
>Greetings!
> > Go to http://www.msn.americangreetings.com/index_msn.pd?source=msne134
> >
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > --
> > Author: David Boyd
> > INET: davidb158_at_hotmail.com
> >
> > Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> > San Diego, California -- Mailing list and web hosting services
> > ---------------------------------------------------------------------
> > To REMOVE yourself from this mailing list, send an E-Mail message
> > to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> > the message BODY, include a line containing: UNSUB ORACLE-L
> > (or the name of mailing list you want to be removed from). You may
> > also send the HELP command for other information (like subscribing).
> >
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.net
>--
>Author: Arup Nanda
> INET: orarup_at_hotmail.com
>
>Fat City Network Services -- 858-538-5051 http://www.fatcity.com
>San Diego, California -- Mailing list and web hosting services
>---------------------------------------------------------------------
>To REMOVE yourself from this mailing list, send an E-Mail message
>to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
>the message BODY, include a line containing: UNSUB ORACLE-L
>(or the name of mailing list you want to be removed from). You may
>also send the HELP command for other information (like subscribing).

Add MSN 8 Internet Software to your current Internet access and enjoy patented spam control and more. Get two months FREE! http://join.msn.com/?page=dept/byoa

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: David Boyd
  INET: davidb158_at_hotmail.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).

Received on Tue Oct 28 2003 - 11:04:25 CST

Re: Refresh option for Materialized view , want to use it during refresh - for