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1、hbasehbase 源码学习之源码学习之 putputhbase-0.90.5一,首先来看下 put 的构造函数：ts 为时间戳，public Put(byte row) this(row, null);， public Put(byte row, RowLock rowLock) this(row, HConstants.LATEST_TIMESTAMP, rowLock);， public Put(byte row, RowLock rowLock) this(row, HConstants.LATEST_TIMESTAMP, rowLock);，public Put(byte row,
2、 long ts) this(row, ts, null);，public Put(byte row, long ts, RowLock rowLock) if(row = null | row.length HConstants.MAX_ROW_LENGTH) throw new IllegalArgumentException(“Row key is invalid“);this.row = Arrays.copyOf(row, row.length);this.timestamp = ts;if(rowLock != null) this.lockId = rowLock.getLock
3、Id();看到的时候很明显了，有传入的参数 key，如果时间戳为空，则为 null，如果传入的 rowlock 不为空，那么就通过 rowLock.getLockId()拿到 lockId,赋值给当前 lockid. 638 棋牌 http:/另外还有个public Put(Put putToCopy) Copy constructor. Creates a Put operation cloned from the specified Put.this.writeToWAL = putToCopy.writeToWAL;HBase 中 WAL（Write Ahead Log） 的存储格式二，
4、add 操作：public Put add(byte family, byte qualifier, long ts, byte value) List list = getKeyValueList(family);KeyValue kv = createPutKeyValue(family, qualifier, ts, value);list.add(kv);familyMap.put(kv.getFamily(), list);return this;List list先取出依据 family 从 familyMap 拿到 List list，如果 list 为空，则创建一个 list,
5、然后依据参数 family, qualifier, ts, value 生成一个 KeyValue然后将 KeyValue 放入 familyMap 中private List getKeyValueList(byte family) List list = familyMap.get(family);if(list = null) list = new ArrayList(0);return list;早来看下 htable 的 put 方法：private void doPut(final List puts) throws IOException int n = 0;for (Put p
6、ut : puts) validatePut(put);writeBuffer.add(put);currentWriteBufferSize += put.heapSize();/ we need to periodically see if the writebuffer is full instead of waiting until the end of the Listn+;if (n % DOPUT_WB_CHECK = 0 if (autoFlush | currentWriteBufferSize writeBufferSize) flushCommits();如果 curre
7、ntWriteBufferSize writeBufferSize，此时就会调用 flushCommits()方法。天地棋牌 http:/Overridepublic void flushCommits() throws IOException try connection.processBatchOfPuts(writeBuffer, tableName, pool); finally if (clearBufferOnFail) writeBuffer.clear();currentWriteBufferSize = 0; else / the write buffer was adjus
8、ted by processBatchOfPutscurrentWriteBufferSize = 0;for (Put aPut : writeBuffer) currentWriteBufferSize += aPut.heapSize();HConnectionManager.classconnection.processBatchOfPuts(writeBuffer, tableName, pool);最终调用的是 processBatch(List) list, tableName, pool, results);方法processBatch 内部有 retry 机制，/ sleep
9、 first, if this is a retrysleep 时间： long sleepTime = getPauseTime(tries);此后回依据参数调用 locateRegion 的去定位 RegionHRegionLocation loc = locateRegion(tableName, row.getRow(), true);private HRegionLocation locateRegion(final byte tableName,final byte row, boolean useCache)在这个函数中：if (Bytes.equals(tableName, H
10、Constants.ROOT_TABLE_NAME) try HServerAddress hsa =this.rootRegionTracker.waitRootRegionLocation(this.rpcTimeout);LOG.debug(“Lookedup root region location, connection=“ + this +“; hsa=“ + hsa);if (hsa = null) return null;return new HRegionLocation(HRegionInfo.ROOT_REGIONINFO, hsa); catch (Interrupte
11、dException e) Thread.currentThread().interrupt();return null; else if (Bytes.equals(tableName, HConstants.META_TABLE_NAME) return locateRegionInMeta(HConstants.ROOT_TABLE_NAME, tableName, row,useCache, metaRegionLock); else / Region not in the cache - have to go to the meta RSreturn locateRegionInMe
12、ta(HConstants.META_TABLE_NAME, tableName, row,useCache, userRegionLock);， 如果 tableName = -ROOT- 就会调用 waitRootRegionLocation 方法，通过zookeeper 得到 rootregion 的地址。返回一个 new HRegionLocation(HRegionInfo.ROOT_REGIONINFO, hsa); 通过 zookeeper 得到 rootregion 的地址:RootRegionTracker.class-public HServerAddress waitRo
13、otRegionLocation(long timeout)throws InterruptedException return dataToHServerAddress(super.blockUntilAvailable(timeout);ZooKeeperNodeTracker.class 中：public synchronized byte blockUntilAvailable(long timeout)throws InterruptedException if (timeout 0) continue;wait(remaining);remaining = timeout - (S
14、ystem.currentTimeMillis() - startTime);return data;在 start 方法中可以看到 data:byte data = ZKUtil.getDataAndWatch(watcher, node);， 如果 tableName = .META.，就会调用 locateRegionInMeta 方法，locateRegionInMeta(HConstants.ROOT_TABLE_NAME, tableName, row,useCache, metaRegionLock);locateRegionInMeta 中：if (useCache) loca
15、tion = getCachedLocation(tableName, row);先去从缓存中拿，如果缓存中没有，得到 metakey，依据这个 key 首先定位 root 和meta region,然后HRegionInterface server =getHRegionConnection(metaLocation.getServerAddress();通过去定位 serveraddress,首先是通过 regionInfoRow = server.getClosestRowBefore 得到一个 regionInfoRow，在得到一个value,regionInfoRow.getValu
16、e,最终得到 serveraddress：serverAddress = Bytes.toString(value);， 如果不是.META.表也不是-ROOT-表，那么也会调用 locateRegionInMeta 方法， / Region not in the cache - have to go to the meta RSreturn locateRegionInMeta(HConstants.META_TABLE_NAME, tableName, row,useCache, userRegionLock);传入 meta 表，定位获得 serveraddress之后组装 actions，即 put，get,delete,等操作之后交给线程池一步
