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HBASE-2023 Client sync block can cause 1 thread of a multi-threaded client to block all others 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@922163 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Michael Stack 2010-03-12 07:22:24 +00:00
parent 3098604a01
commit 9adc7f52b2
1 changed files with 29 additions and 15 deletions
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44
core/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java
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@ -631,16 +631,12 @@ public class HConnectionManager implements HConstants {
return this.rootRegionLocation;
}
} else if (Bytes.equals(tableName, META_TABLE_NAME)) {
synchronized (metaRegionLock) {
// This block guards against two threads trying to load the meta
// region at the same time. The first will load the meta region and
// the second will use the value that the first one found.
return locateRegionInMeta(ROOT_TABLE_NAME, tableName, row, useCache);
}
return locateRegionInMeta(ROOT_TABLE_NAME, tableName, row, useCache,
metaRegionLock);
} else {
synchronized(userRegionLock){
return locateRegionInMeta(META_TABLE_NAME, tableName, row, useCache);
}
// Region not in the cache - have to go to the meta RS
return locateRegionInMeta(META_TABLE_NAME, tableName, row, useCache,
userRegionLock);
}
}
@ -650,18 +646,17 @@ public class HConnectionManager implements HConstants {
*/
@SuppressWarnings({"ConstantConditions"})
private HRegionLocation locateRegionInMeta(final byte [] parentTable,
final byte [] tableName, final byte [] row, boolean useCache)
final byte [] tableName, final byte [] row, boolean useCache,
Object regionLockObject)
throws IOException {
HRegionLocation location;
// If supposed to be using the cache, then check it for a possible hit.
// Otherwise, delete any existing cached location so it won't interfere.
// If we are supposed to be using the cache, look in the cache to see if
// we already have the region.
if (useCache) {
location = getCachedLocation(tableName, row);
if (location != null) {
return location;
}
} else {
deleteCachedLocation(tableName, row);
}
// build the key of the meta region we should be looking for.
@ -681,10 +676,29 @@ public class HConnectionManager implements HConstants {
HRegionInterface server =
getHRegionConnection(metaLocation.getServerAddress());
Result regionInfoRow = null;
// This block guards against two threads trying to load the meta
// region at the same time. The first will load the meta region and
// the second will use the value that the first one found.
synchronized(regionLockObject) {
// Check the cache again for a hit in case some other thread made the
// same query while we were waiting on the lock. If not supposed to
// be using the cache, delete any existing cached location so it won't
// interfere.
if (useCache) {
location = getCachedLocation(tableName, row);
if (location != null) {
return location;
}
} else {
deleteCachedLocation(tableName, row);
}
// Query the root or meta region for the location of the meta region
Result regionInfoRow = server.getClosestRowBefore(
regionInfoRow = server.getClosestRowBefore(
metaLocation.getRegionInfo().getRegionName(), metaKey,
HConstants.CATALOG_FAMILY);
}
if (regionInfoRow == null) {
throw new TableNotFoundException(Bytes.toString(tableName));
}