IDS 11 Compression question
Mike Magie asked whether unloading from a compressed IDS 11 table gives compressed data that needs a compressed target table. Jacques Renaut said unloads return normal uncompressed data, with HPL internal format as a possible exception. Art Kagel confirmed unload files are not compressed and load into compressed, partly compressed or uncompressed tables.
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We do large scale loads and unloads of tables - i.e. unload Table A on Instance A and load all the data into Table B on Instance B. When peforming an unload from a compressed table the data is in compressed format right? So a subsequent load using that data would need to be loaded into a table that also has compression enabled - right? MM
You wrote: We do large scale loads and unloads of tables - i.e. unload Table A on Instance A and load all the data into Table B on Instance B. When peforming an unload from a compressed table the data is in compressed format right? So a subsequent load using that data would need to be loaded into a table that also has compression enabled - right? MM No, when you unload from a compressed table, the data is uncompressed and returned in it's normal form. Same as if you just selected * from the table, the data is uncompressed before being returned as data to clients. However, if you were using HPL and doing an internal data format unload (the kind that unloads the raw storage pages if I remember right) I'm not sure what you get or if you could load that data into a new instance. I haven't played around with HPL and compressed tables. Jacques Renaut IBM Informix Advanced Support APD team
Well when you are done testing the HPL stuff let us all know what you find out...
I was kidding about you testing this... I can have it tested in a few minutes after I get 11.5 downloaded. As a customer I'd rather have the Advance Support guys working on things other than HPL tests... MM
No. Just like SELECT results aren't compressed, unload files are not either. And you can load them into a compressed table or a partially compressed table or an uncompressed table. Art Art S. Kagel Oninit (www.oninit.com) IIUG Board of Directors (art@iiug.org) Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Oninit, the IIUG, nor any other organization with which I am associated either explicitly or implicitly. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Tue, Nov 24, 2009 at 3:04 PM, MIKE MAGIE <jmmagie@yahoo.com> wrote: > We do large scale loads and unloads of tables - i.e. unload Table A on > Instance A and load all the data into Table B on Instance B. > > When peforming an unload from a compressed table the data is in compressed > format right? So a subsequent load using that data would need to be loaded > into a table that also has compression enabled - right? > > MM > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --001517478ccef4ad6804793d5c64