Bala Kolla created JENA-801:
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Summary: When the server is under load, many queries are piling up
and seems to be in some kind of dead lock.
Key: JENA-801
URL: https://issues.apache.org/jira/browse/JENA-801
Project: Apache Jena
Issue Type: Bug
Components: TDB
Affects Versions: Jena 2.11.2, TDB 0.9.4
Reporter: Bala Kolla
We were testing our server with repositories of varied sizes and in almost all
the cases when the server peaks its capacity (of maximum number of users it can
support), It seems like the queries are piling up because of the lock
contention in NodeTableCache.
Here are some details about the repository..
size of indices on disk - 150GB
type of hard disk used - SSD and HDD with high RAM (seeing the same result in
both the cases)
OS - Linux
Details on the user load;
We are trying to simulate a very active user load where all the users are
executing many usecases that would result in many queries and updates on TDB.
I would like to know what are the possible solutions to work around and avoid
this situation. I am thinking of the following, please let me know if there is
any other way to work around this bottleneck.
Control the updates to the triple store so that we only do it when there are
not many queries pending. We would have to experiment how this impact the
usecases..
Is there any other way to make this lock contention go away? Can we have
multiple instances of this cache? For example many (90%) of our queries are
executed with a query scope (per project). So, can we have a separate NodeTable
cache for each query scope (project in our case) and one for global?
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