/**
* Prepare the merged region and region files.
*
* @param server Hosting server instance. Can be null when testing
* @param services Used to online/offline regions.
* @return merged region
* @throws IOException If thrown, transaction failed. Call {@link #rollback(Server,
* RegionServerServices)}
*/
HRegion createMergedRegion(final Server server, final RegionServerServices services)
throws IOException {
LOG.info(
"Starting merge of "
+ region_a
+ " and "
+ region_b.getRegionNameAsString()
+ ", forcible="
+ forcible);
if ((server != null && server.isStopped()) || (services != null && services.isStopping())) {
throw new IOException("Server is stopped or stopping");
}
if (rsCoprocessorHost != null) {
if (rsCoprocessorHost.preMerge(this.region_a, this.region_b)) {
throw new IOException(
"Coprocessor bypassing regions " + this.region_a + " " + this.region_b + " merge.");
}
}
// If true, no cluster to write meta edits to or to use coordination.
boolean testing =
server == null
? true
: server.getConfiguration().getBoolean("hbase.testing.nocluster", false);
HRegion mergedRegion = stepsBeforePONR(server, services, testing);
@MetaMutationAnnotation List<Mutation> metaEntries = new ArrayList<Mutation>();
if (rsCoprocessorHost != null) {
if (rsCoprocessorHost.preMergeCommit(this.region_a, this.region_b, metaEntries)) {
throw new IOException(
"Coprocessor bypassing regions " + this.region_a + " " + this.region_b + " merge.");
}
try {
for (Mutation p : metaEntries) {
HRegionInfo.parseRegionName(p.getRow());
}
} catch (IOException e) {
LOG.error(
"Row key of mutation from coprocessor is not parsable as region name."
+ "Mutations from coprocessor should only be for hbase:meta table.",
e);
throw e;
}
}
// This is the point of no return. Similar with SplitTransaction.
// IF we reach the PONR then subsequent failures need to crash out this
// regionserver
this.journal.add(JournalEntry.PONR);
// Add merged region and delete region_a and region_b
// as an atomic update. See HBASE-7721. This update to hbase:meta makes the region
// will determine whether the region is merged or not in case of failures.
// If it is successful, master will roll-forward, if not, master will
// rollback
if (!testing && useCoordinationForAssignment) {
if (metaEntries.isEmpty()) {
MetaTableAccessor.mergeRegions(
server.getConnection(),
mergedRegion.getRegionInfo(),
region_a.getRegionInfo(),
region_b.getRegionInfo(),
server.getServerName(),
region_a.getTableDesc().getRegionReplication());
} else {
mergeRegionsAndPutMetaEntries(
server.getConnection(),
mergedRegion.getRegionInfo(),
region_a.getRegionInfo(),
region_b.getRegionInfo(),
server.getServerName(),
metaEntries,
region_a.getTableDesc().getRegionReplication());
}
} else if (services != null && !useCoordinationForAssignment) {
if (!services.reportRegionStateTransition(
TransitionCode.MERGE_PONR,
mergedRegionInfo,
region_a.getRegionInfo(),
region_b.getRegionInfo())) {
// Passed PONR, let SSH clean it up
throw new IOException(
"Failed to notify master that merge passed PONR: "
+ region_a.getRegionInfo().getRegionNameAsString()
+ " and "
+ region_b.getRegionInfo().getRegionNameAsString());
}
}
return mergedRegion;
}
