private HRegion openRegion(
final FileSystem fs,
final Path dir,
final HTableDescriptor htd,
final WALFactory wals,
final long whenToRoll,
final LogRoller roller)
throws IOException {
// Initialize HRegion
HRegionInfo regionInfo = new HRegionInfo(htd.getTableName());
// Initialize WAL
final WAL wal = wals.getWAL(regionInfo.getEncodedNameAsBytes());
// If we haven't already, attach a listener to this wal to handle rolls and metrics.
if (walsListenedTo.add(wal)) {
roller.addWAL(wal);
wal.registerWALActionsListener(
new WALActionsListener.Base() {
private int appends = 0;
@Override
public void visitLogEntryBeforeWrite(
HTableDescriptor htd, WALKey logKey, WALEdit logEdit) {
this.appends++;
if (this.appends % whenToRoll == 0) {
LOG.info("Rolling after " + appends + " edits");
// We used to do explicit call to rollWriter but changed it to a request
// to avoid dead lock (there are less threads going on in this class than
// in the regionserver -- regionserver does not have the issue).
DefaultWALProvider.requestLogRoll(wal);
}
}
@Override
public void postSync(final long timeInNanos, final int handlerSyncs) {
syncMeter.mark();
syncHistogram.update(timeInNanos);
syncCountHistogram.update(handlerSyncs);
}
@Override
public void postAppend(final long size, final long elapsedTime) {
appendMeter.mark(size);
}
});
}
return HRegion.createHRegion(regionInfo, dir, getConf(), htd, wal);
}
