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https://issues.apache.org/jira/browse/ASTERIXDB-1433?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15281182#comment-15281182
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Murtadha Hubail commented on ASTERIXDB-1433:
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The buffer cache size must be smaller than the nc.java.opts.
nc.java.opts value is the complete memory budget for the NC. This value must
be divided between the buffer cache, LSM memory components, log buffers,
join/sort operators memory, and any other runtime memory objects. If the
combination of any of these exceeds the nc.java.opts value, you will start
getting out of memory errors.
> Multiple cores with huge memory slow down in the big fact table aggregation.
> ----------------------------------------------------------------------------
>
> Key: ASTERIXDB-1433
> URL: https://issues.apache.org/jira/browse/ASTERIXDB-1433
> Project: Apache AsterixDB
> Issue Type: Improvement
> Components: Hyracks Core
> Environment: 10 nodes X Linux ubuntu/6 cpu X 4 cores/per cpu, 128 GB
> memory/per node.
> Reporter: Wenhai
>
> This is a classic hardware platform that shoes up the TB scale of dataset in
> total. AsterixDB does extremely well for the complex query that includes
> multiple join operators over a high-selectivity select operator. However, the
> running trace results demonstrate that, as compared to the big memory
> configurations, the original tables is always re-loaded from the disk to the
> actual memory even they have been handled in the latest query. To this end,
> why not provide the strategy to keep the intermediate data of the last
> completed query into the memory and free them in case the memory is not
> enough for the newly query. In some case, the user will always trigger the
> query with the different parameters on the same tables, for example, the
> variant-parameter aggregation on the single big fact table.
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