[jira] [Updated] (SVN-4832) Authz perf regression 1.9 -> 1.10

     [ https://issues.apache.org/jira/browse/SVN-4832?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Julian Foad updated SVN-4832:
-----------------------------
    Description: 
TL;DR: since 1.10, Subversion is loading the acl/authz file ~15x times slower in some cases, depending on the authz file contents.

This leads to performance regression in tunnel mode used with svn+ssh scheme.

It also leads to performance regression in HTTP configurations. The parsed authz file result is only cached per Apache httpd "connection". How often re-parsing occurs therefore depends on httpd configurations like MaxConnectionsPerChild (old name MaxRequestsPerChild), and MaxRequestWorkers.

Re-parsing also occurs whenever the authz file has been updated. This might be rare in many deployments but I have investigated one deployment where the authz file was updated every few minutes and this magnified the problem.

Email thread on dev@: "Authz perf regression 1.9 -> 1.10", 2019-09-11, Sam Toliman. [https://svn.haxx.se/dev/archive-2019-09/0033.shtml] or [https://lists.apache.org/thread/4vzo7tddyv556vs372kxb4hz83lomcdr]

  was:
TLDR since 1.10 subversion loading acl file ~15x times slower, which leads in performance regression in tunnel mode used with svn+ssh scheme.

Email thread on dev@: "Authz perf regression 1.9 -> 1.10", 2019-09-11, Sam Toliman. [https://svn.haxx.se/dev/archive-2019-09/0033.shtml] or [https://lists.apache.org/thread/4vzo7tddyv556vs372kxb4hz83lomcdr]


> Authz perf regression 1.9 -> 1.10
> ---------------------------------
>
>                 Key: SVN-4832
>                 URL: https://issues.apache.org/jira/browse/SVN-4832
>             Project: Subversion
>          Issue Type: Bug
>    Affects Versions: 1.10.x
>            Reporter: Julian Foad
>            Priority: Major
>         Attachments: acl.anon, svn-4832-authz-perf-debug-1.patch
>
>
> TL;DR: since 1.10, Subversion is loading the acl/authz file ~15x times slower in some cases, depending on the authz file contents.
> This leads to performance regression in tunnel mode used with svn+ssh scheme.
> It also leads to performance regression in HTTP configurations. The parsed authz file result is only cached per Apache httpd "connection". How often re-parsing occurs therefore depends on httpd configurations like MaxConnectionsPerChild (old name MaxRequestsPerChild), and MaxRequestWorkers.
> Re-parsing also occurs whenever the authz file has been updated. This might be rare in many deployments but I have investigated one deployment where the authz file was updated every few minutes and this magnified the problem.
> Email thread on dev@: "Authz perf regression 1.9 -> 1.10", 2019-09-11, Sam Toliman. [https://svn.haxx.se/dev/archive-2019-09/0033.shtml] or [https://lists.apache.org/thread/4vzo7tddyv556vs372kxb4hz83lomcdr]



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