Could someone kindly give me some help? Thanks. Regards, -Liang
2013/5/29 liang cheng <[email protected]> > Hi, all > In our production environment, the Jackrabbit Journal table would > become large (more than 100, 000 records) after running 2 weeks. As a > result, we plan to utilize the janitor thread to remove old revisions > mentioned in http://wiki.apache.org/jackrabbit/Clustering#Removing Old > Revisions. > After enabling it, there would be several caveats as mentioned in the > wiki page too. > 1. If the janitor is enabled then you loose the possibility to > easily add cluster nodes. (It is still possible but takes detailed > knowledge of Jackrabbit.) > 2. You must make sure that all cluster nodes have written their > local revision to the database before the clean-up task runs for the first > time because otherwise cluster nodes might miss updates (because they > have been purged) and their local caches and search-indexes get out of > sync. > 3. If a cluster node is removed permanently from the cluster, then > its entry in the LOCAL_REVISIONS table should be removed manually. > Otherwise, the clean-up thread will not be effective. > > I can understand point #3.But not quite sure about #1 and #2. > > #1 is our biggest concern. In our production environment, we have cases > to need add new cluster node(s), e.g. If system capacity could not handle > current workload, or if some running node needs to be stopped for some > while for maintenance and then new node needs to be added. In #1, you only > say that "you loose the possibility to easily add cluster nodes", but > doesn't give more explaination about the reason. As I know, when new node > is added into the JR cluster, there is no lucene index, then Jackrabbit > would build the index for the whole current repository nodes (build from > root node). After this step, Jackrabbit then process the revisions > generated by other nodes. *I wonder what's the possible issue when > processing old revisions with latest repository content in cache and > indexes? > * > > For #2, *does it mean any manual work needed to keep the consistency?* > > > > Although the wiki page give one approch to add new cluster node manually > (i.e. clone indexes and local revision number from existing node), we still > hope there is some safe programming way to avoid the manual work, because > our production is deployed in Amazon EC2 environment and adding new node > needs easily as much as possible. > > Could you please give some comments to my concerns? Thanks. > > > Regards, > > -Liang > > > > > > > >
