materialized views have the create statements in the database. you just have to refresh them.
can you refersh a materialized view in parallel? if not than create can be faster...
>
> From: "David Boyd" <davidb158_at_hotmail.com>
> Date: 2003/10/28 Tue PM 12:04:25 EST
> 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
>
> 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:
>
> 1. create table t that is always accessed by applications
> 2. create table t1 that is a temp table for loading
> 3. load data into table t1
> 4. rename table t to table t2
> 5. rename table t1 to t
> 6. rename table t2 to t1
> 7. 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
> > > >
> > >
> > > _________________________________________________________________
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> >Greetings!
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> > >
> > > --
> > > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > > --
> > > Author: David Boyd
> > > INET: davidb158_at_hotmail.com
> > >
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> >--
> >Author: Arup Nanda
> > INET: orarup_at_hotmail.com
> >
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> INET: davidb158_at_hotmail.com
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Received on Tue Oct 28 2003 - 13:14:40 CST
