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Facing Issue : ALLOCATION failed to find 256000000B free.

  • 1.  Facing Issue : ALLOCATION failed to find 256000000B free.

    Posted 07-03-2019 04:18
    Edited by Ishika [[Unknown]] 07-03-2019 04:56
    Hi,

    Sometimes, when executing any select query then not getting the ouput and in OMNISCI logs, getting:

    ALLOCATION failed to find 256000000B free. Forcing Eviction. Eviction start 0 Number pages requested 500000 Best Eviction Start Slab 0 CPU_MGR:0

    Executing the queries on CPU(Not using GPU card)

    omnisql> \memory_summary
    OmniSci Server CPU Memory Summary:
    MAX USE ALLOCATED FREE
    154528.53 MB 122311.86 MB 126976.00 MB 4664.14 MB

    OmniSci Server GPU Memory Summary:
    [GPU] MAX USE ALLOCATED FREE

    Thanks

    #Uncategorized


  • 2.  RE: Facing Issue : ALLOCATION failed to find 256000000B free.

    Posted 07-03-2019 07:43
    Could you give us an example of a query that's failing, numerosity of records on tables involved and possibly the DDLs of tables?
    You can try to run the \clear_cpu command the next time you will face the issue; this would help us to better understand what's happening

    ​​


  • 3.  RE: Facing Issue : ALLOCATION failed to find 256000000B free.

    Posted 07-03-2019 11:03
    Hi,

    Thanks for reply.

    Query is Select count(*) from temp;

    2 billion records are present in temp table.
    DDL :
    CREATE TABLE TEMP (
    Date1 date,
    hour1 integer,
    name varchar(500),
    id varchar(50),
    Total bigint,
    oct_in bigint,
    oct_out bigint);

    I have already executed \clear_cpu command. This issue resolved for sometime but again this issue pops up after sometime and then again I need to run this command. So I am looking for a permanent solution.

    Thanks





  • 4.  RE: Facing Issue : ALLOCATION failed to find 256000000B free.

    Posted 07-03-2019 13:29
    HI @Ishika,
    I didn't suggest the \clear_cpu as a solution nor a workaround, but just to know if after running that command the system was usable.
    I'll try to reproduce (I'm assuming you are running different queries before the count) and it's likely you are hitting a bug on memory manager.
    I'll report back asap


  • 5.  RE: Facing Issue : ALLOCATION failed to find 256000000B free.

    Posted 07-09-2019 03:08
    Hi @Candido Dessanti,

    ​Thanks for reply.

    Yes, I am running different queries before the count. Please suggest for this issue and waiting for your response.

    Thanks


  • 6.  RE: Facing Issue : ALLOCATION failed to find 256000000B free.

    Posted 07-09-2019 07:25
    Hi,

    I'm sorry both I've not be able to reproduce the issue; maybe it's a cardinality problem... how many distinct values has the ID field?

    i have 1508100000 of records with just 5041 different IDs; this is enough to saturate an instance constrained at 55GB of memory, but while I'm hitting the limits, I can run queries without any issue


  • 7.  RE: Facing Issue : ALLOCATION failed to find 256000000B free.

    Posted 07-09-2019 21:52
    Edited by Ishika [[Unknown]] 07-10-2019 01:56
    Hi @Candido Dessanti,

    I have 7000000000​ of records with some 500000 different IDs.

    Thanks



  • 8.  RE: Facing Issue : ALLOCATION failed to find 256000000B free.

    Posted 07-10-2019 02:10
    Ok I'll try to reproduce with such cardinalities, and report back