saintstack commented on a change in pull request #2496:
URL: https://github.com/apache/hbase/pull/2496#discussion_r499705325
##########
File path:
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceManager.java
##########
@@ -1181,57 +1184,63 @@ MetricsReplicationGlobalSourceSource getGlobalMetrics()
{
/**
* Add an hbase:meta Catalog replication source. Called on open of an
hbase:meta Region.
- * @see #removeCatalogReplicationSource()
+ * Create it once only. If exists already, use the existing one.
+ * @see #removeCatalogReplicationSource(RegionInfo)
*/
- public ReplicationSourceInterface addCatalogReplicationSource() throws
IOException {
- // Open/Create the hbase:meta ReplicationSource once only.
+ public ReplicationSourceInterface addCatalogReplicationSource(RegionInfo
regionInfo)
+ throws IOException {
+ // Poor-man's putIfAbsent
synchronized (this.catalogReplicationSource) {
ReplicationSourceInterface rs = this.catalogReplicationSource.get();
return rs != null ? rs :
-
this.catalogReplicationSource.getAndSet(createCatalogReplicationSource());
+
this.catalogReplicationSource.getAndSet(createCatalogReplicationSource(regionInfo));
}
}
/**
* Remove the hbase:meta Catalog replication source.
* Called when we close hbase:meta.
- * @see #addCatalogReplicationSource()
+ * @see #addCatalogReplicationSource(RegionInfo regionInfo)
*/
- public void removeCatalogReplicationSource() {
+ public void removeCatalogReplicationSource(RegionInfo regionInfo) {
// Nothing to do. Leave any CatalogReplicationSource in place in case an
hbase:meta Region
// comes back to this server.
}
/**
* Create, initialize, and start the Catalog ReplicationSource.
*/
- private ReplicationSourceInterface createCatalogReplicationSource() throws
IOException {
- // Has the hbase:meta WALProvider been instantiated?
+ private ReplicationSourceInterface createCatalogReplicationSource(RegionInfo
regionInfo)
+ throws IOException {
+ // Instantiate walProvider if not done already. Can be instantiated here
but also over
+ // in the #warmupRegion call made by the Master on a 'move' operation.
+ // We need to do extra work if we did NOT instantiate the provider.
WALProvider walProvider = this.walFactory.getMetaWALProvider();
- boolean addListener = false;
- if (walProvider == null) {
- // The meta walProvider has not been instantiated. Create it.
+ boolean instantiate = walProvider == null;
+ if (instantiate) {
+ // Instantiate the meta walProvider.
walProvider = this.walFactory.getMetaProvider();
- addListener = true;
}
CatalogReplicationSourcePeer peer = new
CatalogReplicationSourcePeer(this.conf,
this.clusterId.toString(), "meta_" +
ServerRegionReplicaUtil.REGION_REPLICA_REPLICATION_PEER);
final ReplicationSourceInterface crs = new CatalogReplicationSource();
crs.init(conf, fs, this, new NoopReplicationQueueStorage(), peer, server,
peer.getId(),
clusterId, walProvider.getWALFileLengthProvider(), new
MetricsSource(peer.getId()));
- if (addListener) {
- walProvider.addWALActionsListener(new WALActionsListener() {
- @Override
- public void postLogRoll(Path oldPath, Path newPath) throws IOException
{
- crs.enqueueLog(newPath);
- }
- });
- } else {
- // This is a problem. We'll have a ReplicationSource but no listener on
hbase:meta WALs
- // so nothing will be replicated.
- LOG.error("Did not install WALActionsListener creating
CatalogReplicationSource!");
+ WALActionsListener listener = new WALActionsListener() {
+ @Override public void postLogRoll(Path oldPath, Path newPath) throws
IOException {
+ crs.enqueueLog(newPath);
+ }
+ };
+ walProvider.addWALActionsListener(listener);
+ if (!instantiate) {
+ // If we did not instantiate provider, need to add our listener on
already-created WAL
+ // instance too (listeners are passed by provider to WAL instance on
creation but if provider
+ // created already, our listener add above is missed). Add the current
WAL file to the
+ // Replication Source so it can start replicating it.
+ WAL wal = walProvider.getWAL(regionInfo);
Review comment:
Thanks for taking a look.
The reasoning is that this is the one place we add a listener on the meta
WALProvider which we only visit once when we create the meta ReplicationSource
Let me add more doc on this to try and make it more clear.
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