compression on datetime data type

Hi, A table has a datetime (year to seconday) data type, every day this table increase about 1300,0000 records,in those records the portion of year to day always are the same value.Do IDS compress the year/month/day value when I compress the table? Thanks for your help.

Hi, yes, Informix Server will compress the date value. But the compression is done row (or page) wise, not column wise. Hence the compression for the date value itself probably is just average, but not better. With so many records added every day, you may want to look into using the TimeSeries Datablade. (It comes free with Informix Server 11.70.) This Datablade implements its own data type specifically for records with very similar datetime values and is best suited for values of regular intervals. In the latter case it basically can omit storing the datetime values, saving the space and thus also the I/O. If you are also doing a lot of range queries on the datetime value, then TimeSeries Datablade offers a lot of specific and efficient functions for that. For more information on the TimeSeries Datablade I recommend a presentation from our chief architect Kevin Brown (start reading at slide 4 onwards). You can find it in developerWorks: https://www.ibm.com/developerworks/wikis/download/attachments/115998972/TimeSeri es+RTL+Leveraging+Power+of+Informix-OOOv2.pdf?version=1 Or read the TimeSeries Data User's Guide: http://publib.boulder.ibm.com/infocenter/idshelp/v117/index.jsp?topic=/com.ibm.t ms.doc/tms.htm Regards, Martin -- Martin Fuerderer IBM Informix Development Munich, Germany Information Management Read about the Informix Warehouse Accelerator: http://tinyurl.com/the-iwa-blog IBM Deutschland Research & Development GmbH Chairman of the Supervisory Board: Martin Jetter Board of Management: Dirk Wittkopp Corporate Seat: Boeblingen, Germany Reg.-Gericht: Amtsgericht Stuttgart, HRB 243294 ids-bounces@iiug.org wrote on 06/16/2011 08:34:27 AM: > > Hi, > > A table has a datetime (year to seconday) data type, every day this table > increase about 1300,0000 records,in those records the portion of year to day > always are the same value.Do IDS compress the year/month/day value when I > compress the table? > > Thanks for your help. > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. >

Table compression in Informix is LZW style, so any pattern of repeating bytes will be compressed, yes. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. 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 Thu, Jun 16, 2011 at 2:34 AM, CHUAN LU <luchuan114@sina.com> wrote: > Hi, > > A table has a datetime (year to seconday) data type, every day this table > increase about 1300,0000 records,in those records the portion of year to > day > always are the same value.Do IDS compress the year/month/day value when I > compress the table? > > Thanks for your help. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --20cf307f37cefeccd804a5d36903