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Posted to commits@hbase.apache.org by st...@apache.org on 2017/06/14 04:49:15 UTC
hbase git commit: HBASE-18216 [AMv2] Workaround for HBASE-18152,
corrupt procedure WAL
Repository: hbase
Updated Branches:
refs/heads/master cb88b6462 -> 0b43353bf
HBASE-18216 [AMv2] Workaround for HBASE-18152, corrupt procedure WAL
Project: http://git-wip-us.apache.org/repos/asf/hbase/repo
Commit: http://git-wip-us.apache.org/repos/asf/hbase/commit/0b43353b
Tree: http://git-wip-us.apache.org/repos/asf/hbase/tree/0b43353b
Diff: http://git-wip-us.apache.org/repos/asf/hbase/diff/0b43353b
Branch: refs/heads/master
Commit: 0b43353bf76f19e020e2831691a832722b590915
Parents: cb88b64
Author: Michael Stack <st...@apache.org>
Authored: Fri Jun 2 15:38:53 2017 -0700
Committer: Michael Stack <st...@apache.org>
Committed: Tue Jun 13 21:48:28 2017 -0700
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.../store/wal/ProcedureWALFormatReader.java | 93 +++++++++++++++-----
1 file changed, 69 insertions(+), 24 deletions(-)
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http://git-wip-us.apache.org/repos/asf/hbase/blob/0b43353b/hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/ProcedureWALFormatReader.java
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diff --git a/hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/ProcedureWALFormatReader.java b/hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/ProcedureWALFormatReader.java
index 0a05e6e..4d644f7 100644
--- a/hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/ProcedureWALFormatReader.java
+++ b/hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/ProcedureWALFormatReader.java
@@ -44,7 +44,7 @@ public class ProcedureWALFormatReader {
private static final Log LOG = LogFactory.getLog(ProcedureWALFormatReader.class);
// ==============================================================================================
- // We read the WALs in reverse order. from the newest to the oldest.
+ // We read the WALs in reverse order from the newest to the oldest.
// We have different entry types:
// - INIT: Procedure submitted by the user (also known as 'root procedure')
// - INSERT: Children added to the procedure <parentId>:[<childId>, ...]
@@ -53,7 +53,8 @@ public class ProcedureWALFormatReader {
//
// In the WAL we can find multiple times the same procedure as UPDATE or INSERT.
// We read the WAL from top to bottom, so every time we find an entry of the
- // same procedure, that will be the "latest" update.
+ // same procedure, that will be the "latest" update (Caveat: with multiple threads writing
+ // the store, this assumption does not hold).
//
// We keep two in-memory maps:
// - localProcedureMap: is the map containing the entries in the WAL we are processing
@@ -65,7 +66,7 @@ public class ProcedureWALFormatReader {
//
// The WAL is append-only so the last procedure in the WAL is the one that
// was in execution at the time we crashed/closed the server.
- // given that, the procedure replay order can be inferred by the WAL order.
+ // Given that, the procedure replay order can be inferred by the WAL order.
//
// Example:
// WAL-2: [A, B, A, C, D]
@@ -78,7 +79,7 @@ public class ProcedureWALFormatReader {
// WAL-2 localProcedureMap.replayOrder is [D, C, A, B]
// WAL-1 localProcedureMap.replayOrder is [F, G]
//
- // each time we reach the WAL-EOF, the "replayOrder" list is merged/appended in 'procedureMap'
+ // Each time we reach the WAL-EOF, the "replayOrder" list is merged/appended in 'procedureMap'
// so using the example above we end up with: [D, C, A, B] + [F, G] as replay order.
//
// Fast Start: INIT/INSERT record and StackIDs
@@ -183,12 +184,12 @@ public class ProcedureWALFormatReader {
procedureMap.mergeTail(localProcedureMap);
//if (hasFastStartSupport) {
- // TODO: Some procedure may be already runnables (see readInitEntry())
- // (we can also check the "update map" in the log trackers)
- // --------------------------------------------------
- //EntryIterator iter = procedureMap.fetchReady();
- //if (iter != null) loader.load(iter);
- // --------------------------------------------------
+ // TODO: Some procedure may be already runnables (see readInitEntry())
+ // (we can also check the "update map" in the log trackers)
+ // --------------------------------------------------
+ //EntryIterator iter = procedureMap.fetchReady();
+ //if (iter != null) loader.load(iter);
+ // --------------------------------------------------
//}
}
}
@@ -224,7 +225,7 @@ public class ProcedureWALFormatReader {
}
private void readInitEntry(final ProcedureWALEntry entry)
- throws IOException {
+ throws IOException {
assert entry.getProcedureCount() == 1 : "Expected only one procedure";
loadProcedure(entry, entry.getProcedure(0));
}
@@ -319,12 +320,25 @@ public class ProcedureWALFormatReader {
protected ProcedureProtos.Procedure proto;
protected boolean ready = false;
- public Entry(Entry hashNext) { this.hashNext = hashNext; }
+ public Entry(Entry hashNext) {
+ this.hashNext = hashNext;
+ }
+
+ public long getProcId() {
+ return proto.getProcId();
+ }
+
+ public long getParentId() {
+ return proto.getParentId();
+ }
+
+ public boolean hasParent() {
+ return proto.hasParentId();
+ }
- public long getProcId() { return proto.getProcId(); }
- public long getParentId() { return proto.getParentId(); }
- public boolean hasParent() { return proto.hasParentId(); }
- public boolean isReady() { return ready; }
+ public boolean isReady() {
+ return ready;
+ }
public boolean isFinished() {
if (!hasParent()) {
@@ -443,11 +457,17 @@ public class ProcedureWALFormatReader {
public void add(ProcedureProtos.Procedure procProto) {
trackProcIds(procProto.getProcId());
Entry entry = addToMap(procProto.getProcId(), procProto.hasParentId());
- boolean isNew = entry.proto == null;
- entry.proto = procProto;
+ boolean newEntry = entry.proto == null;
+ // We have seen procedure WALs where the entries are out of order; see HBASE-18152.
+ // To compensate, only replace the Entry procedure if for sure this new procedure
+ // is indeed an entry that came later. TODO: Fix the writing of procedure info so
+ // it does not violate basic expectation, that WALs contain procedure changes going
+ // from start to finish in sequence.
+ if (newEntry || isIncreasing(entry.proto, procProto)) {
+ entry.proto = procProto;
+ }
addToReplayList(entry);
-
- if (isNew) {
+ if(newEntry) {
if (procProto.hasParentId()) {
childUnlinkedHead = addToLinkList(entry, childUnlinkedHead);
} else {
@@ -456,6 +476,21 @@ public class ProcedureWALFormatReader {
}
}
+ /**
+ * @return True if this new procedure is 'richer' than the current one else
+ * false and we log this incidence where it appears that the WAL has older entries
+ * appended after newer ones. See HBASE-18152.
+ */
+ private static boolean isIncreasing(ProcedureProtos.Procedure current,
+ ProcedureProtos.Procedure candidate) {
+ boolean increasing = current.getStackIdCount() < candidate.getStackIdCount() &&
+ current.getLastUpdate() <= candidate.getLastUpdate();
+ if (!increasing) {
+ LOG.warn("NOT INCREASING! current=" + current + ", candidate=" + candidate);
+ }
+ return increasing;
+ }
+
public boolean remove(long procId) {
trackProcIds(procId);
Entry entry = removeFromMap(procId);
@@ -634,7 +669,7 @@ public class ProcedureWALFormatReader {
}
/*
- * (see the comprehensive explaination in the beginning of the file)
+ * (see the comprehensive explanation in the beginning of the file)
* A Procedure is ready when parent and children are ready.
* "ready" means that we all the information that we need in-memory.
*
@@ -651,9 +686,9 @@ public class ProcedureWALFormatReader {
* - easy case, the parent is missing from the global map
* - more complex case we look at the Stack IDs.
*
- * The Stack-IDs are added to the procedure order as incremental index
+ * The Stack-IDs are added to the procedure order as an incremental index
* tracking how many times that procedure was executed, which is equivalent
- * at the number of times we wrote the procedure to the WAL.
+ * to the number of times we wrote the procedure to the WAL.
* In the example above:
* wal-2: B has stackId = [1, 2]
* wal-1: B has stackId = [1]
@@ -663,7 +698,7 @@ public class ProcedureWALFormatReader {
* we notice that there is a gap in the stackIds of B, so something was
* executed before.
* To identify when a Procedure is ready we do the sum of the stackIds of
- * the procedure and the parent. if the stackIdSum is equals to the
+ * the procedure and the parent. if the stackIdSum is equal to the
* sum of {1..maxStackId} then everything we need is available.
*
* Example-2
@@ -695,6 +730,10 @@ public class ProcedureWALFormatReader {
int stackId = 1 + rootEntry.proto.getStackId(i);
maxStackId = Math.max(maxStackId, stackId);
stackIdSum += stackId;
+ if (LOG.isTraceEnabled()) {
+ LOG.trace("stackId=" + stackId + " stackIdSum=" + stackIdSum +
+ " maxStackid=" + maxStackId + " " + rootEntry);
+ }
}
for (Entry p = rootEntry.childHead; p != null; p = p.linkNext) {
@@ -702,8 +741,14 @@ public class ProcedureWALFormatReader {
int stackId = 1 + p.proto.getStackId(i);
maxStackId = Math.max(maxStackId, stackId);
stackIdSum += stackId;
+ if (LOG.isTraceEnabled()) {
+ LOG.trace("stackId=" + stackId + " stackIdSum=" + stackIdSum +
+ " maxStackid=" + maxStackId + " " + p);
+ }
}
}
+ // The cmpStackIdSum is this formula for finding the sum of a series of numbers:
+ // http://www.wikihow.com/Sum-the-Integers-from-1-to-N#/Image:Sum-the-Integers-from-1-to-N-Step-2-Version-3.jpg
final int cmpStackIdSum = (maxStackId * (maxStackId + 1) / 2);
if (cmpStackIdSum == stackIdSum) {
rootEntry.ready = true;