/**
* Reduces the number of rows held in this Cache object.
*
* <p>Cleanup is done by checking the accessCount of the Rows and removing the rows with the
* lowest access count.
*
* <p>Index operations require that up to 5 recently accessed rows remain in the cache.
*/
private synchronized void cleanUp() throws IOException {
int removeCount = cacheMap.size() / 2;
int accessTarget = cacheMap.getAccessCountCeiling(removeCount, removeCount / 8);
ObjectCacheHashMap.ObjectCacheIterator it = cacheMap.iterator();
int savecount = 0;
for (; it.hasNext(); ) {
CachedObject r = (CachedObject) it.next();
if (it.getAccessCount() <= accessTarget) {
if (!r.isKeepInMemory()) {
if (r.hasChanged()) {
rowTable[savecount++] = r;
}
it.remove();
cacheBytesLength -= r.getStorageSize();
}
}
}
cacheMap.setAccessCountFloor(accessTarget);
saveRows(savecount);
}
/** Adds a row to the cache. */
public synchronized void put(int key, CachedObject row) throws IOException {
int storageSize = row.getStorageSize();
if (cacheMap.size() >= capacity || storageSize + cacheBytesLength > bytesCapacity) {
cleanUp();
}
cacheMap.put(key, row);
cacheBytesLength += storageSize;
}
/** Removes an object from memory cache. Does not release the file storage. */
public synchronized CachedObject release(int i) {
CachedObject r = (CachedObject) cacheMap.remove(i);
if (r == null) {
return null;
}
cacheBytesLength -= r.getStorageSize();
return r;
}
/** Writes out all modified cached Rows. */
public synchronized void saveAll() throws IOException {
Iterator it = cacheMap.iterator();
int savecount = 0;
for (; it.hasNext(); ) {
CachedObject r = (CachedObject) it.next();
if (r.hasChanged()) {
rowTable[savecount++] = r;
}
}
saveRows(savecount);
Trace.printSystemOut(saveAllTimer.elapsedTimeToMessage("Cache.saveRow() total row save time"));
Trace.printSystemOut("Cache.saveRow() total row save count = " + saveRowCount);
Trace.printSystemOut(makeRowTimer.elapsedTimeToMessage("Cache.makeRow() total row load time"));
Trace.printSystemOut("Cache.makeRow() total row load count = " + makeRowCount);
Trace.printSystemOut(sortTimer.elapsedTimeToMessage("Cache.sort() total time"));
}
public int size() {
return cacheMap.size();
}
/** clears out the memory cache */
synchronized void clear() {
cacheMap.clear();
cacheBytesLength = 0;
}
/** Returns a row if in memory cache. */
public synchronized CachedObject get(int pos) {
return (CachedObject) cacheMap.get(pos);
}