GitHub user mike-jumper opened a pull request:
https://github.com/apache/incubator-guacamole-client/pull/60
GUACAMOLE-76: Fix N+1 problem when querying connection group tree.
Speed of the connection group tree REST resource fell dramatically with the
addition of sharing profiles. This is because the
`getSharingProfileIdentifiers()` function of `Connection` issues a new query
for every call, and is not affected by retrieval of connections in batches via
`getAll()` on the `Directory<Connection>`.
This change addresses this by retrieving child object identifiers when the
parents are retrieved. If multiple parents are retrieved, the identifiers of
each of their children is retrieved with *one query* (rather than *N queries*).
This is accomplished through issuing multiple `SELECT` statements within the
same logical query defined in the MyBatis mapping. Beware that while PostgreSQL
will handle multiple statements within a single query by default, the MySQL
JDBC driver requires a special `allowMultiQueries` property for this.
We should look into making the connection tree retrieval process more
efficient, as there are definitely ways it could be sped up (use breadth-first
only if attempts to retrieve the entire directory contents at once fail?), but
this should fix things with respect to release-blocking regressions. Query
performance should be back to where it was.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/mike-jumper/incubator-guacamole-client
connection-group-tree-speed
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-guacamole-client/pull/60.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #60
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commit a83b5c585c5df63e6254dc62a88d1752fbcfa88e
Author: Michael Jumper <[email protected]>
Date: 2016-08-20T05:03:15Z
GUACAMOLE-76: Query child object identifiers directly.
commit 2e3d3c4f5fba477ede71ea8a831a2c66dd0b4f37
Author: Michael Jumper <[email protected]>
Date: 2016-08-20T19:41:16Z
GUACAMOLE-76: Set "allowMultiQueries" for MySQL.
commit 5794338b8d46ea36fc99716f13bba26944c5934d
Author: Michael Jumper <[email protected]>
Date: 2016-08-20T19:41:48Z
GUACAMOLE-76: Clean MySQL and PostgreSQL modules for consistency.
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