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https://issues.apache.org/jira/browse/QPID-7666?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robbie Gemmell updated QPID-7666:
---------------------------------
    Fix Version/s: qpid-cpp-1.37.0

Setting fix-version for 1.37.0.

> [linearstore] Enhancements to the write buffer default and per-queue options
> ----------------------------------------------------------------------------
>
>                 Key: QPID-7666
>                 URL: https://issues.apache.org/jira/browse/QPID-7666
>             Project: Qpid
>          Issue Type: Improvement
>          Components: C++ Broker
>    Affects Versions: qpid-cpp-1.37.0
>            Reporter: Kim van der Riet
>            Assignee: Kim van der Riet
>             Fix For: qpid-cpp-1.37.0
>
>
> In applications where large numbers of persistent queues are created on a 
> single broker, control over the default and per-queue store options are 
> important so that resources are not wasted or become exhausted prematurely.
> There are two resources of concern:
> # Memory allocated per queue for buffering;
> # Disk resources consumed for journal files.
> Currently, the default setting for memory allocation is 1024kiB/queue (ie 32 
> pages of 32kiB). The only default setting available is the page size (using 
> the {{wcache-page-size}} option), and the number of pages is set internally 
> according to the following table:
> ||{{wcache-page-size}}||{{wcache-num-pages}}||total mmap||
> ||(kiB)||(set interanlly)||(kiB)||
> |  4   |  64 |    256 |
> |  8   |  64 |    512|
> | 16   | 32 |    512|
> | 32*  | 32 |   1024|
> | 64   | 16 |   1024|
> |128   |  8 |   1024|
> \* default
> This gives in effect only 3 per-queue memory allocation options: 256kiB, 
> 512kiB and 1024kiB.
> Currently, the values of {{wcache-page-size}} is limited to the powers of 2 
> between 4 and 128.
> It is suggested that the {{wcache-num-pages}} value be set as as an option 
> rather than internally, which would give the user much greater control over 
> the per-queue memory footprint and the buffer geometry (which can be 
> optimized for the disk hardware and queue load characteristics).
> In addition, the upper value limit on {{wcache-page-size}} should be removed 
> (as it is rather arbitrary) and the default value should be revised.
> Further, it would be valuable to add these parameters to {{qpid-config}} so 
> that if a queue is created using this tool, the default values for the store 
> parameters can be overridden on a per-queue basis.
> Disk resource controls are currently in place for the EFP partition 
> ({{efp-partition}}) and the size of the EFP files ({{efp-file-size}}), both 
> as a default and in {{qpid-config}}. The default values should also be 
> revised.



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