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https://issues.apache.org/jira/browse/DIRSTUDIO-1174?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16439010#comment-16439010
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Stefan Seelmann commented on DIRSTUDIO-1174:
--------------------------------------------
Loading of the schema from the LDAP server happens in
ReloadSchemaRunnable.java, method reloadSchema(). That is called when opening
the connection or when forcing the reload of the schema.
Your are right, with your change the schema is always loaded from the server
(because the modifyTimestamp of an empyt Schema object is null). However
looking into the mustReload() method I think the logic there is wrong an if the
cached schema is null or empty the schema is not loaded from the server.
> Directory Studio startup very slow due to schema LDIF processing
> ----------------------------------------------------------------
>
> Key: DIRSTUDIO-1174
> URL: https://issues.apache.org/jira/browse/DIRSTUDIO-1174
> Project: Directory Studio
> Issue Type: Bug
> Components: studio-connection
> Affects Versions: 2.0.0-M13
> Environment: openSUSE Linux (installed on my laptop)
> Sun/Oracle Java 1.8.0_111 (previously 1.7 with same issue)
> Apache Directory Studio 2.0.0 M12 and M13, plus earlier milestones too
> Reporter: Aaron Burgemeister
> Priority: Major
> Labels: LDIF, schema, startup-time
> Attachments: 20180415-no-load-schema-ldif-by-default.patch
>
>
> For the past couple years startup of Apache Directory Studio has slowed down
> to the point where it takes more than a minute on my not-a-slouch laptop to
> start. Other systems, VMs with new installs, start much faster, even on the
> same laptop, implying something other than the base product is at fault. As
> a result, I had suspected maybe Directory Studio slowed down precipitously
> due to the number of stored connections, but never confirmed the same.
> Today I connected strace to the 'java' process as it started and noticed the
> following:
>
> [pid 30108] *1521902717*.154740
> open("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core/schema-ba001fb7-4b83-4dca-be44-517c14139f4b.ldif",
> O_RDONLY) = *-1 ENOENT (No such file or directory)*
> [pid 30108] *1521902717*.154906
> stat("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core",
> \{st_mode=S_IFDIR|0755, st_size=5378, ...}) = 0
> [pid 30108] *1521902717*.154948
> open("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core/schema-95e1202e-9a67-418c-afe9-b02f4e7c06df.ldif",
> O_RDONLY) = *-1 ENOENT (No such file or directory)*
> [pid 30108] *1521902717*.155019
> stat("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core",
> \{st_mode=S_IFDIR|0755, st_size=5378, ...}) = 0
> [pid 30108] *1521902717*.155053
> open("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core/schema-687f43f6-9d05-4d08-b159-35b0e76dc95a.ldif",
> O_RDONLY) = *-1 ENOENT (No such file or directory)*
> [pid 30108] *1521902717*.155120
> stat("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core",
> \{st_mode=S_IFDIR|0755, st_size=5378, ...}) = 0
> [pid 30108] *1521902717*.155154
> open("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core/schema-d62d0e10-c81e-4477-81a2-ac2c9e5c7169.ldif",
> O_RDONLY) = *121*
> [pid 30108] *1521902718*.698702
> stat("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core",
> \{st_mode=S_IFDIR|0755, st_size=5378, ...}) = 0
> [pid 30108] *1521902718*.698800
> open("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core/schema-7b6a9a7c-2192-4b24-8874-1378e5b1b30c.ldif",
> O_RDONLY) = *126*
> [pid 30108] *1521902719*.770570
> stat("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core",
> \{st_mode=S_IFDIR|0755, st_size=5378, ...}) = 0
> [pid 30108] *1521902719*.770660
> open("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core/schema-b3b02838-067f-4f24-bf92-6bf3fccdbc52.ldif",
> O_RDONLY) = *127*
> [pid 30108] *1521902721*.198417
> stat("/home/ab/.ApacheDirectoryStudio/.metadata/.plugins/org.apache.directory.studio.ldapbrowser.core",
> \{st_mode=S_IFDIR|0755, st_size=5378, ...}) = 0
>
> Notice the timestamps (bolded near beginning of line) and how they change
> based on whether or not a schema LDIF file was found (bolded near end of
> line) and, presumably, processed. When a file is not found, subsequent files
> are sought immediately without significantly delaying startup.
> These schema files are all under 1 MiB in size, but most of them are several
> hundred KiBs, approaching the 1 MiB size, so depending on what Directory
> Studio is doing as it reads and processes these files, it would seem that
> this introduces the slowness when a file is found.
> Looking for an existing issue I found DIRSTUDIO-1027 which may be related.
> During startup of Directory Studio one of my laptop's eight cores is fully
> utilized, which makes me think this may be more about processing the LDIF
> than just swapping memory due to inefficient data structures, but I am not a
> memory management expert, so I only mention the possibility here in case it
> helps find the root cause quickly.
> My Directory Studio's total startup time: sixty-one (61) seconds.
> Time spent (per strace) reading schema files: fifty-five (55) seconds.
> Estimated non-schema startup time: six (6) seconds.
>
> Steps to duplicate:
> Have a lot, e.g. 100, of stored schema LDIF files from previous connections.
> Startup Apache Directory Studio.
> Expected results: Startup quickly. Processing old schema LDIFs, when most of
> them will not be used at any given time, seems like a waste of time in
> general. Perhaps this can be done only when a connection is accessed in some
> way rather than at startup.
> Actual results: Slow startup.
> Reproducible: I think so, but am not sure why my system has these schema
> LDIFs when others may not.
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