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Design size of Collections

by wolf at 22-8-2008 20:49; Wiki ID: CollectionSize

What is the optimal number of documents in a collection?

With current eXist versions you have to find a compromise between query speed and update costs: storing all documents into a single collection results in fast queries. The drawback is that removing or replacing documents can become really slow! On the other hand, using one collection per document would guarantee that document updates run in linear time, but the query overhead would be considerable.

So if you need reasonable fast updates, the recommendation is to keep the number of documents in one collection below 2000 or so. Otherwise, if you never delete documents, you can easily store some 100,000 docs into one collection.

We plan to redesign the current index organization in the coming months.

eXist-db does not work/install on RedHat, Ubuntu, Linux

by wolf at 22-8-2008 20:31; Wiki ID: LinuxInstall

Probably you use the default installed java version, gnu classpath/gjc. We recommend the Sun JVM, but JVMs of other vendors should work as well

Search for "gjc" in the errormessages:

java.lang.ArrayIndexOutOfBoundsException
   at java.lang.System.arraycopy(libgcj.so.70)
   at java.io.ObjectInputStream.read(libgcj.so.70 )
   at java.io.InputStream.skip(libgcj.so.70)
   at com.izforge.izpack.installer.Unpacker.run(Unpacker.java:425)
   at java.lang.Thread.run(libgcj.so.70)

or

12 Aug 2008 16:34:31,161 [P1-9] WARN  (ServletHandler.java
[handle]:629) - Error for /exist/logo.jpg
java.lang.NoClassDefFoundError: org.apache.cocoon.reading.ImageReader
  at java.lang.Class.initializeClass(libgcj.so.81)
  at java.lang.Class.newInstance(libgcj.so.81)

or

Exception in thread "main" java.lang.InternalError: unexpected exception
during linking: java.lang.ClassNotFoundException: javax.swing.JFrame
  at 0x004f8ca3: java.lang.Throwable.Throwable(java.lang.String)
(/usr/lib/./libgcj.so.3)
  at 0x004ebb1e: java.lang.Error.Error(java.lang.String)
(/usr/lib/./libgcj.so.3)
  at 0x004f9086:
java.lang.VirtualMachineError.VirtualMachineError(java.lang.String)
(/usr/lib/./libgcj.so.3)

ant can help you out to determine the java version:

ant -diagnostics | grep java.vm

or

build.sh diagnostics | grep java.vm

results in

java.vm.version : 1.5.0_13-119
java.vm.vendor : Apple Inc.
java.vm.name : Java HotSpot(TM) Client VM
java.vm.specification.name : Java Virtual Machine Specification
java.vm.specification.vendor : Sun Microsystems Inc.
java.vm.specification.version : 1.0
java.vm.info : mixed mode

Explicit validation does not work in Apache Tomcat

by wolf at 22-8-2008 20:30; Wiki ID: ValidationTomcat

There are indeed limitations regarding the functionality of the "validation:" functions, due to restrictions of tomcat. These are very vague.

eXist-db does not start in Apache Tomcat

by wolf at 22-8-2008 20:30; Wiki ID: TomcatStartup

The war files are tested and should work. Be sure that tomcat is not setup with the "SecurityManager" enabled (we should work this out) and that (for older versions of tomcat) all relevant XML jar files (xerces, resolver, xalan) have been installed in the 'endorsed' directory.

For more information check our documentation.

My webstart client does not start (with log)

by wolf at 22-8-2008 20:28; Wiki ID: webstart

Probably you see something like

An error occurred while launching/running the application.
Title: eXist XML-DB client
Vendor: exist-db.org
Category: Security Error
Unsigned application requesting unrestricted access to system
Unsigned resource: http://localhost:8080/exist/webstart/stax-api-1.0.1.jar

while the exception reads like:

JNLPException[category: Security Error : Exception: null : LaunchDesc: 
<jnlp spec="1.0+" codebase="http://localhost:8080/exist/webstart/"
      href="http://localhost:8080/exist/webstart/exist.jnlp">

The solution is to re-sign the jar files:

build.sh -f build/scripts/jarsigner.xml jnlp-unsign-all jnlp-sign-all
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