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Re: Table Index taking up large quantity of DB space

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It occurs to me to add a little more here.  If the query for the datalengths of the text values shows that there many long text values, then the "LOB Compression" feature can help by reducing the number of pages needed to store each value once it is compressed.  See Compressed Columns with Large Objects.  "Long" meaning larger than what can be stored on one text page which is (1800/3600/7650/16200) bytes* depending on ASE's page size (2k/4k/8k/16k).  In general, the longer the value, the more compression is likely to help shrink it down and free up pages.

 

Compression won't help with very small values because they are still each stored on their own page.

 

Cheers,

-bret

 

*These values and other interesting static limits can be displayed using the "dbcc serverlimits" command, which requires that switch/traceflag 3604 be on:

 

isql -Usa -P -w999

1> set switch on 3604

2> go

Switch 3604 ('print_output_to_client') is turned on.

All supplied switches are successfully turned on.

1> dbcc serverlimits

2> go

[...]

Limits as a function of the page size:
======================================

            Item dependent on page size                             : 2048    4096    8192    16384
----------------------------------------------------------------------------------------------------------

[...]

Text-manager related limits

  Max text size available for user data                             : 1800    3600    7650    16200


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