Different policy for concurrency access in TDB supporting a single writer and
multiple readers
----------------------------------------------------------------------------------------------
Key: JENA-41
URL: https://issues.apache.org/jira/browse/JENA-41
Project: Jena
Issue Type: New Feature
Components: Fuseki, TDB
Reporter: Paolo Castagna
As a follow up to a discussion about "Concurrent updates in TDB" [1] on the
jena-users mailing list, I am creating this as a new feature request.
Currently TDB requires developers to use a Multiple Reader or Single Writer
(MRSW) locking policy for concurrency access [2]. Not doing this could cause
data corruptions.
The MRSW is indeed a MR xor SW (i.e. while a writer has a lock, no readers are
allowed and, similarly, if a reader has a lock, no writes are possible).
This works fine in most of the situation, but there might be problems in
presence of long writes or long reads.
It has been suggested that a "journaled file access" could be used to solve the
issue regarding a long write blocking reads.
[1] http://markmail.org/message/jnqm6pn32df4wgte
[2] http://openjena.org/wiki/TDB/JavaAPI#Concurrency
--
This message is automatically generated by JIRA.
-
For more information on JIRA, see: http://www.atlassian.com/software/jira
