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HBASE-4562 When split doing offlineParentInMeta encounters error, it'll cause data loss 

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1185414 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
larsh 2011-10-17 22:37:33 +00:00
parent 03351581d0
commit 6217443231
2 changed files with 19 additions and 18 deletions
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2
CHANGES.txt
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@ -742,6 +742,8 @@ Release 0.90.5 - Unreleased
HBASE-4570. Fix a race condition that could cause inconsistent results
from scans during concurrent writes. (todd and Jonathan Jsieh
via todd)
HBASE-4562 When split doing offlineParentInMeta encounters error, it'll
cause data loss (bluedavy via Lars H)
IMPROVEMENT
HBASE-4205 Enhance HTable javadoc (Eric Charles)

35
src/main/java/org/apache/hadoop/hbase/regionserver/SplitTransaction.java
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@ -287,13 +287,24 @@ public class SplitTransaction {
this.journal.add(JournalEntry.STARTED_REGION_B_CREATION);
HRegion b = createDaughterRegion(this.hri_b, this.parent.rsServices);
// This is the point of no return. Adding subsequent edits to .META. as we
// do below when we do the daughter opens adding each to .META. can fail in
// various interesting ways the most interesting of which is a timeout
// BUT the edits all go through (See HBASE-3872). IF we reach the PONR
// then subsequent failures need to crash out this regionserver; the
// server shutdown processing should be able to fix-up the incomplete split.
// The offlined parent will have the daughters as extra columns. If
// we leave the daughter regions in place and do not remove them when we
// crash out, then they will have their references to the parent in place
// still and the server shutdown fixup of .META. will point to these
// regions.
// We should add PONR JournalEntry before offlineParentInMeta,so even if
// OfflineParentInMeta timeout,this will cause regionserver exit,and then
// master ServerShutdownHandler will fix daughter & avoid data loss. (See
// HBase-4562).
this.journal.add(JournalEntry.PONR);
// Edit parent in meta. Offlines parent region and adds splita and splitb.
// TODO: This can 'fail' by timing out against .META. but the edits could
// be applied anyways over on the server. There is no way to tell for sure.
// We could try and get the edits again subsequent to their application
// whether we fail or not but that could fail too. We should probably move
// the PONR to here before the edits go in but could mean we'd abort the
// regionserver when we didn't need to; i.e. the edits did not make it in.
if (!testing) {
MetaEditor.offlineParentInMeta(server.getCatalogTracker(),
this.parent.getRegionInfo(), a.getRegionInfo(), b.getRegionInfo());
@ -313,18 +324,6 @@ public class SplitTransaction {
/* package */void openDaughters(final Server server,
final RegionServerServices services, HRegion a, HRegion b)
throws IOException {
// This is the point of no return. Adding subsequent edits to .META. as we
// do below when we do the daughter opens adding each to .META. can fail in
// various interesting ways the most interesting of which is a timeout
// BUT the edits all go through (See HBASE-3872). IF we reach the PONR
// then subsequent failures need to crash out this regionserver; the
// server shutdown processing should be able to fix-up the incomplete split.
// The offlined parent will have the daughters as extra columns. If
// we leave the daughter regions in place and do not remove them when we
// crash out, then they will have their references to the parent in place
// still and the server shutdown fixup of .META. will point to these
// regions.
this.journal.add(JournalEntry.PONR);
boolean stopped = server != null && server.isStopped();
boolean stopping = services != null && services.isStopping();
// TODO: Is this check needed here?