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Former Member

Increased heap memory per user in ASE 15.7

Hi there,

since we updated to ASE 15.7 we noticed more 'heap memory per user' is required for some DML transactions that ran fine in earlier versions (e.g.15.5).

The error message says: There is insufficient heap memory to allocate 65520 bytes. Please increase configuration parameter 'heap memory per user' or try again when there is less activity on the system.

Following the Sybase docs, heap memory per user should be 3 time the page size, in our case 3*4K. But nearly 64K seems to be a big step.

Does anyone else faced similar behavior in 15.7 or can someone explain why this happens in 15.7 only ?

Some details:

- ASE 15.7 SP100 on RHEL 6 (64bit)

- Java application using jTDS



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2 Answers

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    Former Member
    Nov 27, 2013 at 03:56 PM

    There is a relatively loose rule of thumb with any of the recommendations with sizing of memory, caches, etc :  it's only a starting point.  You may end up using more or less. This goes for any DBMS or software vendor really. 😊

    Inch up the heap memory with 2k increments until you find the spot where your queries run without the issue.

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  • Jan 30, 2015 at 09:21 AM

    I found that updating a compressed table with quite a big row size got heap errors.

    Page size is default, 2k, and heap size is 8k.

    Nothing else suffered after we migrated to 15.7 (although I wouldn't know if we had ample heap before and after 15.7 migration were closer to the limit.)  At any rate compression definitely seems to need a bit more.

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