wchevreuil commented on a change in pull request #403: HBASE-22707 [HBCK2]
MasterRpcServices assigns method should try to reload regions from meta if the
passed regions isn't found under AssignmentManager RegionsStateStore
URL: https://github.com/apache/hbase/pull/403#discussion_r307968068
##########
File path:
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java
##########
@@ -1383,51 +1383,76 @@ public void processOfflineRegions() {
}
}
- private void loadMeta() throws IOException {
- // TODO: use a thread pool
- regionStateStore.visitMeta(new RegionStateStore.RegionStateVisitor() {
- @Override
- public void visitRegionState(Result result, final RegionInfo regionInfo,
final State state,
- final ServerName regionLocation, final ServerName lastHost, final
long openSeqNum) {
- if (state == null && regionLocation == null && lastHost == null &&
- openSeqNum == SequenceId.NO_SEQUENCE_ID) {
- // This is a row with nothing in it.
- LOG.warn("Skipping empty row={}", result);
- return;
- }
- State localState = state;
- if (localState == null) {
- // No region state column data in hbase:meta table! Are I doing a
rolling upgrade from
- // hbase1 to hbase2? Am I restoring a SNAPSHOT or otherwise adding a
region to hbase:meta?
- // In any of these cases, state is empty. For now, presume OFFLINE
but there are probably
- // cases where we need to probe more to be sure this correct; TODO
informed by experience.
- LOG.info(regionInfo.getEncodedName() + " regionState=null; presuming
" + State.OFFLINE);
- localState = State.OFFLINE;
- }
- RegionStateNode regionNode =
regionStates.getOrCreateRegionStateNode(regionInfo);
- // Do not need to lock on regionNode, as we can make sure that before
we finish loading
- // meta, all the related procedures can not be executed. The only
exception is for meta
- // region related operations, but here we do not load the informations
for meta region.
- regionNode.setState(localState);
- regionNode.setLastHost(lastHost);
- regionNode.setRegionLocation(regionLocation);
- regionNode.setOpenSeqNum(openSeqNum);
-
- // Note: keep consistent with other methods, see
region(Opening|Opened|Closing)
- // RIT/ServerCrash handling should take care of the transiting
regions.
- if (localState.matches(State.OPEN, State.OPENING, State.CLOSING,
State.SPLITTING,
- State.MERGING)) {
- assert regionLocation != null : "found null region location for " +
regionNode;
- regionStates.addRegionToServer(regionNode);
- } else if (localState == State.OFFLINE || regionInfo.isOffline()) {
- regionStates.addToOfflineRegions(regionNode);
- }
- if (regionNode.getProcedure() != null) {
- regionNode.getProcedure().stateLoaded(AssignmentManager.this,
regionNode);
- }
+ private class RegionMetaLoadingVisitor implements
RegionStateStore.RegionStateVisitor {
+
+ @Override
+ public void visitRegionState(Result result, final RegionInfo regionInfo,
final State state,
+ final ServerName regionLocation, final ServerName lastHost, final long
openSeqNum) {
+ if (state == null && regionLocation == null && lastHost == null &&
+ openSeqNum == SequenceId.NO_SEQUENCE_ID) {
+ // This is a row with nothing in it.
+ LOG.warn("Skipping empty row={}", result);
+ return;
}
- });
+ State localState = state;
+ if (localState == null) {
+ // No region state column data in hbase:meta table! Are I doing a
rolling upgrade from
+ // hbase1 to hbase2? Am I restoring a SNAPSHOT or otherwise adding a
region to hbase:meta?
+ // In any of these cases, state is empty. For now, presume OFFLINE but
there are probably
+ // cases where we need to probe more to be sure this correct; TODO
informed by experience.
+ LOG.info(regionInfo.getEncodedName() + " regionState=null; presuming "
+ State.OFFLINE);
+ localState = State.OFFLINE;
+ }
+ RegionStateNode regionNode =
regionStates.getOrCreateRegionStateNode(regionInfo);
+ // Do not need to lock on regionNode, as we can make sure that before we
finish loading
+ // meta, all the related procedures can not be executed. The only
exception is for meta
+ // region related operations, but here we do not load the informations
for meta region.
+ regionNode.setState(localState);
+ regionNode.setLastHost(lastHost);
+ regionNode.setRegionLocation(regionLocation);
+ regionNode.setOpenSeqNum(openSeqNum);
+
+ // Note: keep consistent with other methods, see
region(Opening|Opened|Closing)
+ // RIT/ServerCrash handling should take care of the transiting
regions.
+ if (localState.matches(State.OPEN, State.OPENING, State.CLOSING,
State.SPLITTING,
+ State.MERGING)) {
+ assert regionLocation != null : "found null region location for " +
regionNode;
+ regionStates.addRegionToServer(regionNode);
+ } else if (localState == State.OFFLINE || regionInfo.isOffline()) {
+ regionStates.addToOfflineRegions(regionNode);
+ }
+ if (regionNode.getProcedure() != null) {
+ regionNode.getProcedure().stateLoaded(AssignmentManager.this,
regionNode);
+ }
+ }
+ };
+
+ /**
+ * Query META if the given <code>RegionInfo</code> exists, adding to
+ * <code>AssignmentManager.regionStateStore</code> cache if the region is
found in META.
+ * @param regionEncodedName encoded name for the region to be loaded from
META into
+ * <code>AssignmentManager.regionStateStore</code>
cache
+ * @return <code>RegionInfo</code> instance for the given region if it is
present in META
+ * and got successfully loaded into
<code>AssignmentManager.regionStateStore</code>
+ * cache, <b>null</b> otherwise.
+ * @throws UnknownRegionException if any errors occur while querying meta.
+ */
+ public RegionInfo loadRegionFromMeta(String regionEncodedName) throws
UnknownRegionException {
+ try {
+ RegionMetaLoadingVisitor visitor = new RegionMetaLoadingVisitor();
+ regionStateStore.visitMetaForRegion(regionEncodedName, visitor);
+ RegionInfo regionInfo = regionStates.getRegionState(regionEncodedName)
== null ? null :
+ regionStates.getRegionState(regionEncodedName).getRegion();
+ return regionInfo;
+ }catch(IOException e){
+ LOG.error("Error trying to load region {} from META", regionEncodedName,
e);
+ throw new UnknownRegionException("Error while trying load region from
meta");
+ }
+ }
+ private void loadMeta() throws IOException {
+ // TODO: use a thread pool
+ regionStateStore.visitMeta(new RegionMetaLoadingVisitor());
// every assignment is blocked until meta is loaded.
wakeMetaLoadedEvent();
}
Review comment:
Thanks!
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