hbase increase
increase代码
1.将数据封装为increment对象
2.从increment对象中封装get
3.封装新kv
4.对HRegion下的Storm做upsert或add操作
5.查看是否需要flush并添加队列
6.返回kvs
HRegion代码，如下
/**
* Perform one or more increment operations on a row.
* @param increment
* @return new keyvalues after increment
* @throws IOException
*/
public Result increment(Increment increment, long nonceGroup, long nonce)
throws IOException {
byte [] row = increment.getRow();
checkRow(row, "increment");
TimeRange tr = increment.getTimeRange();
boolean flush = false;
Durability durability = getEffectiveDurability(increment.getDurability());
boolean writeToWAL = durability != Durability.SKIP_WAL;
WALEdit walEdits = null;
List<Cell> allKVs = new ArrayList<Cell>(increment.size());
Map<Store, List<Cell>> tempMemstore = new HashMap<Store, List<Cell>>();
long size = 0;
long txid = 0;
checkReadOnly();
checkResources();
// Lock row
startRegionOperation(Operation.INCREMENT);
this.writeRequestsCount.increment();
WriteEntry w = null;
try {
RowLock rowLock = getRowLock(row);
try {
lock(this.updatesLock.readLock());
// wait for all prior MVCC transactions to finish - while we hold the row lock
// (so that we are guaranteed to see the latest state)
mvcc.completeMemstoreInsert(mvcc.beginMemstoreInsert());
// now start my own transaction
w = mvcc.beginMemstoreInsert();
try {
long now = EnvironmentEdgeManager.currentTimeMillis();
// Process each family
for (Map.Entry<byte [], List<Cell>> family:
increment.getFamilyCellMap().entrySet()) {
Store store = stores.get(family.getKey());
List<Cell> kvs = new ArrayList<Cell>(family.getValue().size());
// Sort the cells so that they match the order that they
// appear in the Get results. Otherwise, we won't be able to
// find the existing values if the cells are not specified
// in order by the client since cells are in an array list.
Collections.sort(family.getValue(), store.getComparator());
// Get previous values for all columns in this family
// 从increment封装get请求
Get get = new Get(row);
for (Cell cell: family.getValue()) {
KeyValue kv = KeyValueUtil.ensureKeyValue(cell);
get.addColumn(family.getKey(), kv.getQualifier());
}
get.setTimeRange(tr.getMin(), tr.getMax());
List<Cell> results = get(get, false);//获得此increase的row
// Iterate the input columns and update existing values if they were
// found, otherwise add new column initialized to the increment amount
int idx = 0;
for (Cell kv: family.getValue()) {
long amount = Bytes.toLong(CellUtil.cloneValue(kv));//获得当前value值
boolean noWriteBack = (amount == 0);
Cell c = null;
if (idx < results.size() && CellUtil.matchingQualifier(results.get(idx), kv)) {
c = results.get(idx);
if(c.getValueLength() == Bytes.SIZEOF_LONG) {
amount += Bytes.toLong(c.getValueArray(), c.getValueOffset(), Bytes.SIZEOF_LONG);
} else {
// throw DoNotRetryIOException instead of IllegalArgumentException
throw new org.apache.hadoop.hbase.DoNotRetryIOException(
"Attempted to increment field that isn't 64 bits wide");
}
idx++;
}
// Append new incremented KeyValue to list
byte[] q = CellUtil.cloneQualifier(kv);
byte[] val = Bytes.toBytes(amount);
int oldCellTagsLen = (c == null) ? 0 : c.getTagsLength();
int incCellTagsLen = kv.getTagsLength();
KeyValue newKV = new KeyValue(row.length, family.getKey().length, q.length, now,
KeyValue.Type.Put, val.length, oldCellTagsLen + incCellTagsLen);
System.arraycopy(row, 0, newKV.getBuffer(), newKV.getRowOffset(), row.length);
System.arraycopy(family.getKey(), 0, newKV.getBuffer(), newKV.getFamilyOffset(),
family.getKey().length);
System.arraycopy(q, 0, newKV.getBuffer(), newKV.getQualifierOffset(), q.length);
// copy in the value
System.arraycopy(val, 0, newKV.getBuffer(), newKV.getValueOffset(), val.length);
// copy tags
if (oldCellTagsLen > 0) {
System.arraycopy(c.getTagsArray(), c.getTagsOffset(), newKV.getBuffer(),
newKV.getTagsOffset(), oldCellTagsLen);
}
if (incCellTagsLen > 0) {
System.arraycopy(kv.getTagsArray(), kv.getTagsOffset(), newKV.getBuffer(),
newKV.getTagsOffset() + oldCellTagsLen, incCellTagsLen);
}
newKV.setMvccVersion(w.getWriteNumber());
// Give coprocessors a chance to update the new cell
if (coprocessorHost != null) {
newKV = KeyValueUtil.ensureKeyValue(coprocessorHost.postMutationBeforeWAL(
RegionObserver.MutationType.INCREMENT, increment, c, (Cell) newKV));
}
allKVs.add(newKV);
if (!noWriteBack) {
kvs.add(newKV);
// Prepare WAL updates
if (writeToWAL) {
if (walEdits == null) {
walEdits = new WALEdit();
}
walEdits.add(newKV);
}
}
}
//store the kvs to the temporary memstore before writing HLog
if (!kvs.isEmpty()) {
tempMemstore.put(store, kvs);
}
}
// Actually write to WAL now
if (walEdits != null && !walEdits.isEmpty()) {
if (writeToWAL) {
// Using default cluster id, as this can only happen in the orginating
// cluster. A slave cluster receives the final value (not the delta)
// as a Put.
txid = this.log.appendNoSync(this.getRegionInfo(),
this.htableDescriptor.getTableName(), walEdits, new ArrayList<UUID>(),
EnvironmentEdgeManager.currentTimeMillis(), this.htableDescriptor, this.sequenceId,
true, nonceGroup, nonce);
} else {
recordMutationWithoutWal(increment.getFamilyCellMap());
}
}
//Actually write to Memstore now
if (!tempMemstore.isEmpty()) {//更新hbase kv
for (Map.Entry<Store, List<Cell>> entry : tempMemstore.entrySet()) {
Store store = entry.getKey();
if (store.getFamily().getMaxVersions() == 1) {
// upsert if VERSIONS for this CF == 1
size += store.upsert(entry.getValue(), getSmallestReadPoint());
} else {
// otherwise keep older versions around
for (Cell cell : entry.getValue()) {
KeyValue kv = KeyValueUtil.ensureKeyValue(cell);
size += store.add(kv);
}
}
}
size = this.addAndGetGlobalMemstoreSize(size);
flush = isFlushSize(size);
}
} finally {
this.updatesLock.readLock().unlock();
}
} finally {
rowLock.release();
}
if (writeToWAL && (walEdits != null) && !walEdits.isEmpty()) {
// sync the transaction log outside the rowlock
syncOrDefer(txid, durability);
}
} finally {
if (w != null) {
mvcc.completeMemstoreInsert(w);
}
closeRegionOperation(Operation.INCREMENT);
if (this.metricsRegion != null) {
this.metricsRegion.updateIncrement();
}
}
if (flush) {
// Request a cache flush. Do it outside update lock.
requestFlush();
}
return Result.create(allKVs);
}
在一些情况下，如increment压力过大时，会出现下列错误，startNonceOperation方法:
regionserver.ServerNonceManager: Conflict detected by nonce
一个mutation里边有多个相同的nonce的操作，如increment，这样会产生此日志，影响相应速度