/** * 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; }