jackrabbit-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <wikidi...@apache.org>
Subject [Jackrabbit Wiki] Update of "DataStore" by ThomasMueller
Date Thu, 16 Jul 2009 08:35:03 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Jackrabbit Wiki" for change notification.

The following page has been changed by ThomasMueller:
http://wiki.apache.org/jackrabbit/DataStore

------------------------------------------------------------------------------
  
  == File Data Store ==
  
- The file data store stores each binary in a file. The file name is the hash code of the
content. The file data store does not use any local cache, that means content is directly
read from the files as needed. New content is first stored in a temporary file, and later
renamed / moved.
+ The file data store stores each binary in a file. The file name is the hash code of the
content. The file data store does not use any local cache, that means content is directly
read from the files as needed. New content is first stored in a temporary file, and later
renamed / moved to the right place.
+ 
+ When reading, the data is streamed directly from the file (no local or temporary copy of
the file is created).
  
  ==== Configuration ====
  
@@ -52, +54 @@

  
  == Database Data Store ==
  
- The database data store stores data in a relational database. All content is stored in one
table.
+ The database data store stores data in a relational database. All content is stored in one
table. The unique key of the table is the hash code of the content. New content is first stored
in the table under a unique temporary identifier, and later the key is updated to the hash
of the content.
+ 
+ When reading, the data may be first copied to a temporary file on the server, or streamed
directly from the database (depending on the copyWhenReading setting).
  
  ==== Configuration ====
  
@@ -93, +97 @@

  Q: Can I disable the data store? A: Only if there are no elements in the data store. If
there it is not empty, you need to copy the data to a new repository.
  
  Q: When I use the database data store I get the message: 'Table or view does not exists'.
A: Maybe the data store table already exists in another schema. When starting the repository,
the database data store checks if the table already exists (using a database meta data call),
and will create the table if not. If the table exists, but is in another schema, the table
is not created, but accessing it may fail (if the other schema is not in the schema search
path for this user).
+ 
+ Q: What would happen when multiple users download large files from the store? A: DbDataStore:
It depends on whether the copyWhenReading option is enabled or not (see there). FileDataStore:
The same file would be opened multiple times. The file would be in the operating system /
file system block cache, so that wouldn't be a problem.
  
  Clustering is supported if you use a shared file system, such as SAN or NFS (Windows file
sharing works as well). You need to set data store path of all cluster nodes to the same location.
  

Mime
View raw message