[Exist-commits] eXist-1.0/src/org/exist/storage/index CollectionStore.java,1.3,1.4 BFile.java,1.12,1.13

[Wolfgang M. M. <wol...@us...>]

Update of /cvsroot/exist/eXist-1.0/src/org/exist/storage/index
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv21823/src/org/exist/storage/index

Modified Files:
	CollectionStore.java BFile.java 
Log Message:
Improved cache resize policy: eXist uses dynamic caches to adopt to different loads. It is thus important to determine if a page should be grown or shrinked in order to increase cache efficiency. So far, a cache was resized based on the number of page replacements. However, this is a bad measure as replacements can be positive as well as negative.

The new implementation bases the resize decision on the thrashing factor of a cache. Thrashing occurs if a page is replaced from the cache and has to be reloaded shortly after. For the B+-tree pages, we normally don't want any trashing. For the data pages, a certain amount of thrashing is ok.

Additionally, a huge cache can now be shrinked dynamically if a smaller cache requests a resize. Some caches (words.dbx) tend to grow very fast and consume the whole cache space, so there will be no space left for the slower-growing caches. This may lead to a bottleneck if the amount of stored data increases.

Index: BFile.java
===================================================================
RCS file: /cvsroot/exist/eXist-1.0/src/org/exist/storage/index/BFile.java,v
retrieving revision 1.12
retrieving revision 1.13
diff -C2 -d -r1.12 -r1.13
*** BFile.java	27 Aug 2005 07:14:34 -0000	1.12
--- BFile.java	29 Aug 2005 19:30:55 -0000	1.13
***************
*** 142,146 ****
      
      public BFile(BrokerPool pool, byte fileId, boolean transactional, File file, CacheManager cacheManager, 
!             double cacheGrowth, int thresholdBTree, int thresholdData) throws DBException {
          super(pool, fileId, transactional, cacheManager, file, thresholdBTree);
          fileHeader = (BFileHeader) getFileHeader();
--- 142,146 ----
      
      public BFile(BrokerPool pool, byte fileId, boolean transactional, File file, CacheManager cacheManager, 
!             double cacheGrowth, double thresholdBTree, double thresholdData) throws DBException {
          super(pool, fileId, transactional, cacheManager, file, thresholdBTree);
          fileHeader = (BFileHeader) getFileHeader();
***************
*** 1715,1719 ****
                  try {
                      write();
!                     if (isTransactional && syncJournal)
                          logManager.flushToLog(true);
                      return true;
--- 1715,1719 ----
                  try {
                      write();
!                     if (isTransactional && syncJournal && logManager.lastWrittenLsn() < getPageHeader().getLsn())
                          logManager.flushToLog(true);
                      return true;

Index: CollectionStore.java
===================================================================
RCS file: /cvsroot/exist/eXist-1.0/src/org/exist/storage/index/CollectionStore.java,v
retrieving revision 1.3
retrieving revision 1.4
diff -C2 -d -r1.3 -r1.4
*** CollectionStore.java	27 Aug 2005 07:14:34 -0000	1.3
--- CollectionStore.java	29 Aug 2005 19:30:55 -0000	1.4
***************
*** 27,31 ****
  	 */
  	public CollectionStore(BrokerPool pool, File file, CacheManager cacheManager) throws DBException {
! 		super(pool, NativeBroker.COLLECTIONS_DBX_ID, true, file, cacheManager, 1.25, 100, 1000);
  	}
  	
--- 27,31 ----
  	 */
  	public CollectionStore(BrokerPool pool, File file, CacheManager cacheManager) throws DBException {
! 		super(pool, NativeBroker.COLLECTIONS_DBX_ID, true, file, cacheManager, 1.25, 0.01, 0.03);
  	}