View Javadoc

1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.hadoop.hbase;
19  
20  import static org.apache.hadoop.hbase.io.hfile.BlockType.MAGIC_LENGTH;
21  
22  import java.nio.charset.Charset;
23  import java.util.Arrays;
24  import java.util.Collections;
25  import java.util.List;
26  import java.util.UUID;
27  import java.util.regex.Pattern;
28  
29  import org.apache.commons.lang.ArrayUtils;
30  import org.apache.hadoop.hbase.classification.InterfaceAudience;
31  import org.apache.hadoop.hbase.classification.InterfaceStability;
32  import org.apache.hadoop.hbase.util.Bytes;
33  
34  /**
35   * HConstants holds a bunch of HBase-related constants
36   */
37  @InterfaceAudience.Public
38  @InterfaceStability.Stable
39  public final class HConstants {
40    // NOTICE!!!! Please do not add a constants here, unless they are referenced by a lot of classes.
41  
42    //Bytes.UTF8_ENCODING should be updated if this changed
43    /** When we encode strings, we always specify UTF8 encoding */
44    public static final String UTF8_ENCODING = "UTF-8";
45  
46    //Bytes.UTF8_CHARSET should be updated if this changed
47    /** When we encode strings, we always specify UTF8 encoding */
48    public static final Charset UTF8_CHARSET = Charset.forName(UTF8_ENCODING);
49    /**
50     * Default block size for an HFile.
51     */
52    public final static int DEFAULT_BLOCKSIZE = 64 * 1024;
53  
54    /** Used as a magic return value while optimized index key feature enabled(HBASE-7845) */
55    public final static int INDEX_KEY_MAGIC = -2;
56    /*
57       * Name of directory that holds recovered edits written by the wal log
58       * splitting code, one per region
59       */
60    public static final String RECOVERED_EDITS_DIR = "recovered.edits";
61    /**
62     * The first four bytes of Hadoop RPC connections
63     */
64    public static final byte[] RPC_HEADER = new byte[] { 'H', 'B', 'a', 's' };
65    public static final byte RPC_CURRENT_VERSION = 0;
66  
67    // HFileBlock constants. TODO!!!! THESE DEFINES BELONG IN HFILEBLOCK, NOT UP HERE.
68    // Needed down in hbase-common though by encoders but these encoders should not be dealing
69    // in the internals of hfileblocks. Fix encapsulation.
70  
71    /** The size data structures with minor version is 0 */
72    public static final int HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM = MAGIC_LENGTH + 2 * Bytes.SIZEOF_INT
73        + Bytes.SIZEOF_LONG;
74    /** The size of a version 2 HFile block header, minor version 1.
75     * There is a 1 byte checksum type, followed by a 4 byte bytesPerChecksum
76     * followed by another 4 byte value to store sizeofDataOnDisk.
77     */
78    public static final int HFILEBLOCK_HEADER_SIZE = HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM +
79      Bytes.SIZEOF_BYTE + 2 * Bytes.SIZEOF_INT;
80    /** Just an array of bytes of the right size. */
81    public static final byte[] HFILEBLOCK_DUMMY_HEADER = new byte[HFILEBLOCK_HEADER_SIZE];
82  
83    //End HFileBlockConstants.
84  
85    /**
86     * Status codes used for return values of bulk operations.
87     */
88    @InterfaceAudience.Private
89    public enum OperationStatusCode {
90      NOT_RUN,
91      SUCCESS,
92      BAD_FAMILY,
93      SANITY_CHECK_FAILURE,
94      FAILURE;
95    }
96  
97    /** long constant for zero */
98    public static final Long ZERO_L = Long.valueOf(0L);
99    public static final String NINES = "99999999999999";
100   public static final String ZEROES = "00000000000000";
101 
102   // For migration
103 
104   /** name of version file */
105   public static final String VERSION_FILE_NAME = "hbase.version";
106 
107   /**
108    * Current version of file system.
109    * Version 4 supports only one kind of bloom filter.
110    * Version 5 changes versions in catalog table regions.
111    * Version 6 enables blockcaching on catalog tables.
112    * Version 7 introduces hfile -- hbase 0.19 to 0.20..
113    * Version 8 introduces namespace
114    */
115   // public static final String FILE_SYSTEM_VERSION = "6";
116   public static final String FILE_SYSTEM_VERSION = "8";
117 
118   // Configuration parameters
119 
120   //TODO: Is having HBase homed on port 60k OK?
121 
122   /** Cluster is in distributed mode or not */
123   public static final String CLUSTER_DISTRIBUTED = "hbase.cluster.distributed";
124 
125   /** Config for pluggable load balancers */
126   public static final String HBASE_MASTER_LOADBALANCER_CLASS = "hbase.master.loadbalancer.class";
127 
128   /** Config for balancing the cluster by table */
129   public static final String HBASE_MASTER_LOADBALANCE_BYTABLE = "hbase.master.loadbalance.bytable";
130 
131   /** Config for the max percent of regions in transition */
132   public static final String HBASE_MASTER_BALANCER_MAX_RIT_PERCENT =
133       "hbase.master.balancer.maxRitPercent";
134 
135   /** Default value for the max percent of regions in transition */
136   public static final double DEFAULT_HBASE_MASTER_BALANCER_MAX_RIT_PERCENT = 1.0;
137 
138   /** Config for the max balancing time */
139   public static final String HBASE_BALANCER_MAX_BALANCING = "hbase.balancer.max.balancing";
140 
141   /** Config for the balancer period */
142   public static final String HBASE_BALANCER_PERIOD = "hbase.balancer.period";
143 
144   /** Default value for the balancer period */
145   public static final int DEFAULT_HBASE_BALANCER_PERIOD = 300000;
146 
147   /** The name of the ensemble table */
148   public static final String ENSEMBLE_TABLE_NAME = "hbase:ensemble";
149 
150   /** Config for pluggable region normalizer */
151   public static final String HBASE_MASTER_NORMALIZER_CLASS =
152     "hbase.master.normalizer.class";
153 
154   /** Cluster is standalone or pseudo-distributed */
155   public static final boolean CLUSTER_IS_LOCAL = false;
156 
157   /** Cluster is fully-distributed */
158   public static final boolean CLUSTER_IS_DISTRIBUTED = true;
159 
160   /** Default value for cluster distributed mode */
161   public static final boolean DEFAULT_CLUSTER_DISTRIBUTED = CLUSTER_IS_LOCAL;
162 
163   /** default host address */
164   public static final String DEFAULT_HOST = "0.0.0.0";
165 
166   /** Parameter name for port master listens on. */
167   public static final String MASTER_PORT = "hbase.master.port";
168 
169   /** default port that the master listens on */
170   public static final int DEFAULT_MASTER_PORT = 16000;
171 
172   /** default port for master web api */
173   public static final int DEFAULT_MASTER_INFOPORT = 16010;
174 
175   /** Configuration key for master web API port */
176   public static final String MASTER_INFO_PORT = "hbase.master.info.port";
177 
178   /** Parameter name for the master type being backup (waits for primary to go inactive). */
179   public static final String MASTER_TYPE_BACKUP = "hbase.master.backup";
180 
181   /** by default every master is a possible primary master unless the conf explicitly overrides it */
182   public static final boolean DEFAULT_MASTER_TYPE_BACKUP = false;
183 
184   /** Name of ZooKeeper quorum configuration parameter. */
185   public static final String ZOOKEEPER_QUORUM = "hbase.zookeeper.quorum";
186 
187   /** Name of ZooKeeper config file in conf/ directory. */
188   public static final String ZOOKEEPER_CONFIG_NAME = "zoo.cfg";
189 
190   /** Common prefix of ZooKeeper configuration properties */
191   public static final String ZK_CFG_PROPERTY_PREFIX =
192       "hbase.zookeeper.property.";
193 
194   public static final int ZK_CFG_PROPERTY_PREFIX_LEN =
195       ZK_CFG_PROPERTY_PREFIX.length();
196 
197   /**
198    * The ZK client port key in the ZK properties map. The name reflects the
199    * fact that this is not an HBase configuration key.
200    */
201   public static final String CLIENT_PORT_STR = "clientPort";
202 
203   /** Parameter name for the client port that the zookeeper listens on */
204   public static final String ZOOKEEPER_CLIENT_PORT =
205       ZK_CFG_PROPERTY_PREFIX + CLIENT_PORT_STR;
206 
207   /** Default client port that the zookeeper listens on */
208   public static final int DEFAULT_ZOOKEPER_CLIENT_PORT = 2181;
209 
210   /** Parameter name for the wait time for the recoverable zookeeper */
211   public static final String ZOOKEEPER_RECOVERABLE_WAITTIME = "hbase.zookeeper.recoverable.waittime";
212 
213   /** Default wait time for the recoverable zookeeper */
214   public static final long DEFAULT_ZOOKEPER_RECOVERABLE_WAITIME = 10000;
215 
216   /** Parameter name for the root dir in ZK for this cluster */
217   public static final String ZOOKEEPER_ZNODE_PARENT = "zookeeper.znode.parent";
218 
219   public static final String DEFAULT_ZOOKEEPER_ZNODE_PARENT = "/hbase";
220 
221   /**
222    * Parameter name for the limit on concurrent client-side zookeeper
223    * connections
224    */
225   public static final String ZOOKEEPER_MAX_CLIENT_CNXNS =
226       ZK_CFG_PROPERTY_PREFIX + "maxClientCnxns";
227 
228   /** Parameter name for the ZK data directory */
229   public static final String ZOOKEEPER_DATA_DIR =
230       ZK_CFG_PROPERTY_PREFIX + "dataDir";
231 
232   /** Parameter name for the ZK tick time */
233   public static final String ZOOKEEPER_TICK_TIME =
234       ZK_CFG_PROPERTY_PREFIX + "tickTime";
235 
236   /** Default limit on concurrent client-side zookeeper connections */
237   public static final int DEFAULT_ZOOKEPER_MAX_CLIENT_CNXNS = 300;
238 
239   /** Configuration key for ZooKeeper session timeout */
240   public static final String ZK_SESSION_TIMEOUT = "zookeeper.session.timeout";
241 
242   /** Default value for ZooKeeper session timeout */
243   public static final int DEFAULT_ZK_SESSION_TIMEOUT = 180 * 1000;
244 
245   /** Configuration key for whether to use ZK.multi */
246   public static final String ZOOKEEPER_USEMULTI = "hbase.zookeeper.useMulti";
247 
248   /** Parameter name for port region server listens on. */
249   public static final String REGIONSERVER_PORT = "hbase.regionserver.port";
250 
251   /** Default port region server listens on. */
252   public static final int DEFAULT_REGIONSERVER_PORT = 16020;
253 
254   /** default port for region server web api */
255   public static final int DEFAULT_REGIONSERVER_INFOPORT = 16030;
256 
257   /** A configuration key for regionserver info port */
258   public static final String REGIONSERVER_INFO_PORT =
259     "hbase.regionserver.info.port";
260 
261   /** A flag that enables automatic selection of regionserver info port */
262   public static final String REGIONSERVER_INFO_PORT_AUTO =
263       REGIONSERVER_INFO_PORT + ".auto";
264 
265   /** Parameter name for what region server implementation to use. */
266   public static final String REGION_SERVER_IMPL= "hbase.regionserver.impl";
267 
268   /** Parameter name for what master implementation to use. */
269   public static final String MASTER_IMPL= "hbase.master.impl";
270 
271   /** Parameter name for what hbase client implementation to use. */
272   public static final String HBASECLIENT_IMPL= "hbase.hbaseclient.impl";
273 
274   /** Parameter name for how often threads should wake up */
275   public static final String THREAD_WAKE_FREQUENCY = "hbase.server.thread.wakefrequency";
276 
277   /** Default value for thread wake frequency */
278   public static final int DEFAULT_THREAD_WAKE_FREQUENCY = 10 * 1000;
279 
280   /** Parameter name for how often we should try to write a version file, before failing */
281   public static final String VERSION_FILE_WRITE_ATTEMPTS = "hbase.server.versionfile.writeattempts";
282 
283   /** Parameter name for how often we should try to write a version file, before failing */
284   public static final int DEFAULT_VERSION_FILE_WRITE_ATTEMPTS = 3;
285 
286   /** Parameter name for how often a region should should perform a major compaction */
287   public static final String MAJOR_COMPACTION_PERIOD = "hbase.hregion.majorcompaction";
288 
289   /** Parameter name for the maximum batch of KVs to be used in flushes and compactions */
290   public static final String COMPACTION_KV_MAX = "hbase.hstore.compaction.kv.max";
291   public static final int COMPACTION_KV_MAX_DEFAULT = 10;
292 
293   /** Parameter name for HBase instance root directory */
294   public static final String HBASE_DIR = "hbase.rootdir";
295 
296   /** Parameter name for HBase client IPC pool type */
297   public static final String HBASE_CLIENT_IPC_POOL_TYPE = "hbase.client.ipc.pool.type";
298 
299   /** Parameter name for HBase client IPC pool size */
300   public static final String HBASE_CLIENT_IPC_POOL_SIZE = "hbase.client.ipc.pool.size";
301 
302   /** Parameter name for HBase client operation timeout. */
303   public static final String HBASE_CLIENT_OPERATION_TIMEOUT = "hbase.client.operation.timeout";
304 
305   /** Parameter name for HBase client operation timeout. */
306   public static final String HBASE_CLIENT_META_OPERATION_TIMEOUT =
307     "hbase.client.meta.operation.timeout";
308 
309   /** Default HBase client operation timeout, which is tantamount to a blocking call */
310   public static final int DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT = 1200000;
311 
312   /** Parameter name for HBase client meta replica scan call timeout. */
313   public static final String HBASE_CLIENT_META_REPLICA_SCAN_TIMEOUT =
314       "hbase.client.meta.replica.scan.timeout";
315 
316   /** Default HBase client meta replica scan call timeout, 1 second */
317   public static final int HBASE_CLIENT_META_REPLICA_SCAN_TIMEOUT_DEFAULT = 1000000;
318 
319   /** Used to construct the name of the log directory for a region server */
320   public static final String HREGION_LOGDIR_NAME = "WALs";
321 
322   /** Used to construct the name of the splitlog directory for a region server */
323   public static final String SPLIT_LOGDIR_NAME = "splitWAL";
324 
325   /** Like the previous, but for old logs that are about to be deleted */
326   public static final String HREGION_OLDLOGDIR_NAME = "oldWALs";
327 
328   public static final String CORRUPT_DIR_NAME = "corrupt";
329 
330   /** Used by HBCK to sideline backup data */
331   public static final String HBCK_SIDELINEDIR_NAME = ".hbck";
332 
333   /** Any artifacts left from migration can be moved here */
334   public static final String MIGRATION_NAME = ".migration";
335 
336   /**
337    * The directory from which co-processor/custom filter jars can be loaded
338    * dynamically by the region servers. This value can be overridden by the
339    * hbase.dynamic.jars.dir config.
340    */
341   public static final String LIB_DIR = "lib";
342 
343   /** Used to construct the name of the compaction directory during compaction */
344   public static final String HREGION_COMPACTIONDIR_NAME = "compaction.dir";
345 
346   /** Conf key for the max file size after which we split the region */
347   public static final String HREGION_MAX_FILESIZE =
348       "hbase.hregion.max.filesize";
349 
350   /** Default maximum file size */
351   public static final long DEFAULT_MAX_FILE_SIZE = 10 * 1024 * 1024 * 1024L;
352 
353   /**
354    * Max size of single row for Get's or Scan's without in-row scanning flag set.
355    */
356   public static final String TABLE_MAX_ROWSIZE_KEY = "hbase.table.max.rowsize";
357 
358   /**
359    * Default max row size (1 Gb).
360    */
361   public static final long TABLE_MAX_ROWSIZE_DEFAULT = 1024 * 1024 * 1024L;
362 
363   /**
364    * The max number of threads used for opening and closing stores or store
365    * files in parallel
366    */
367   public static final String HSTORE_OPEN_AND_CLOSE_THREADS_MAX =
368     "hbase.hstore.open.and.close.threads.max";
369 
370   /**
371    * The default number for the max number of threads used for opening and
372    * closing stores or store files in parallel
373    */
374   public static final int DEFAULT_HSTORE_OPEN_AND_CLOSE_THREADS_MAX = 1;
375 
376   /**
377    * Block updates if memstore has hbase.hregion.memstore.block.multiplier
378    * times hbase.hregion.memstore.flush.size bytes.  Useful preventing
379    * runaway memstore during spikes in update traffic.
380    */
381   public static final String HREGION_MEMSTORE_BLOCK_MULTIPLIER =
382           "hbase.hregion.memstore.block.multiplier";
383 
384   /**
385    * Default value for hbase.hregion.memstore.block.multiplier
386    */
387   public static final int DEFAULT_HREGION_MEMSTORE_BLOCK_MULTIPLIER = 4;
388 
389   /** Conf key for the memstore size at which we flush the memstore */
390   public static final String HREGION_MEMSTORE_FLUSH_SIZE =
391       "hbase.hregion.memstore.flush.size";
392 
393   public static final String HREGION_EDITS_REPLAY_SKIP_ERRORS =
394       "hbase.hregion.edits.replay.skip.errors";
395 
396   public static final boolean DEFAULT_HREGION_EDITS_REPLAY_SKIP_ERRORS =
397       false;
398 
399   /** Maximum value length, enforced on KeyValue construction */
400   public static final int MAXIMUM_VALUE_LENGTH = Integer.MAX_VALUE - 1;
401 
402   /** name of the file for unique cluster ID */
403   public static final String CLUSTER_ID_FILE_NAME = "hbase.id";
404 
405   /** Default value for cluster ID */
406   public static final String CLUSTER_ID_DEFAULT = "default-cluster";
407 
408   /** Parameter name for # days to keep MVCC values during a major compaction */
409   public static final String KEEP_SEQID_PERIOD = "hbase.hstore.compaction.keep.seqId.period";
410   /** At least to keep MVCC values in hfiles for 5 days */
411   public static final int MIN_KEEP_SEQID_PERIOD = 5;
412 
413   // Always store the location of the root table's HRegion.
414   // This HRegion is never split.
415 
416   // region name = table + startkey + regionid. This is the row key.
417   // each row in the root and meta tables describes exactly 1 region
418   // Do we ever need to know all the information that we are storing?
419 
420   // Note that the name of the root table starts with "-" and the name of the
421   // meta table starts with "." Why? it's a trick. It turns out that when we
422   // store region names in memory, we use a SortedMap. Since "-" sorts before
423   // "." (and since no other table name can start with either of these
424   // characters, the root region will always be the first entry in such a Map,
425   // followed by all the meta regions (which will be ordered by their starting
426   // row key as well), followed by all user tables. So when the Master is
427   // choosing regions to assign, it will always choose the root region first,
428   // followed by the meta regions, followed by user regions. Since the root
429   // and meta regions always need to be on-line, this ensures that they will
430   // be the first to be reassigned if the server(s) they are being served by
431   // should go down.
432 
433 
434   /**
435    * The hbase:meta table's name.
436    * @deprecated For upgrades of 0.94 to 0.96
437    */
438   @Deprecated  // for compat from 0.94 -> 0.96.
439   public static final byte[] META_TABLE_NAME = TableName.META_TABLE_NAME.getName();
440 
441   public static final String BASE_NAMESPACE_DIR = "data";
442 
443   /** delimiter used between portions of a region name */
444   public static final int META_ROW_DELIMITER = ',';
445 
446   /** The catalog family as a string*/
447   public static final String CATALOG_FAMILY_STR = "info";
448 
449   /** The catalog family */
450   public static final byte [] CATALOG_FAMILY = Bytes.toBytes(CATALOG_FAMILY_STR);
451 
452   /** The RegionInfo qualifier as a string */
453   public static final String REGIONINFO_QUALIFIER_STR = "regioninfo";
454 
455   /** The regioninfo column qualifier */
456   public static final byte [] REGIONINFO_QUALIFIER = Bytes.toBytes(REGIONINFO_QUALIFIER_STR);
457 
458   /** The server column qualifier */
459   public static final String SERVER_QUALIFIER_STR = "server";
460   /** The server column qualifier */
461   public static final byte [] SERVER_QUALIFIER = Bytes.toBytes(SERVER_QUALIFIER_STR);
462 
463   /** The startcode column qualifier */
464   public static final String STARTCODE_QUALIFIER_STR = "serverstartcode";
465   /** The startcode column qualifier */
466   public static final byte [] STARTCODE_QUALIFIER = Bytes.toBytes(STARTCODE_QUALIFIER_STR);
467 
468   /** The open seqnum column qualifier */
469   public static final String SEQNUM_QUALIFIER_STR = "seqnumDuringOpen";
470   /** The open seqnum column qualifier */
471   public static final byte [] SEQNUM_QUALIFIER = Bytes.toBytes(SEQNUM_QUALIFIER_STR);
472 
473   /** The state column qualifier */
474   public static final String STATE_QUALIFIER_STR = "state";
475 
476   public static final byte [] STATE_QUALIFIER = Bytes.toBytes(STATE_QUALIFIER_STR);
477 
478   /**
479    * The serverName column qualifier. Its the server where the region is
480    * transitioning on, while column server is the server where the region is
481    * opened on. They are the same when the region is in state OPEN.
482    */
483   public static final String SERVERNAME_QUALIFIER_STR = "sn";
484 
485   public static final byte [] SERVERNAME_QUALIFIER = Bytes.toBytes(SERVERNAME_QUALIFIER_STR);
486 
487   /** The lower-half split region column qualifier */
488   public static final byte [] SPLITA_QUALIFIER = Bytes.toBytes("splitA");
489 
490   /** The upper-half split region column qualifier */
491   public static final byte [] SPLITB_QUALIFIER = Bytes.toBytes("splitB");
492 
493   /** The lower-half merge region column qualifier */
494   public static final byte[] MERGEA_QUALIFIER = Bytes.toBytes("mergeA");
495 
496   /** The upper-half merge region column qualifier */
497   public static final byte[] MERGEB_QUALIFIER = Bytes.toBytes("mergeB");
498 
499   /**
500    * The meta table version column qualifier.
501    * We keep current version of the meta table in this column in <code>-ROOT-</code>
502    * table: i.e. in the 'info:v' column.
503    */
504   public static final byte [] META_VERSION_QUALIFIER = Bytes.toBytes("v");
505 
506   /**
507    * The current version of the meta table.
508    * - pre-hbase 0.92.  There is no META_VERSION column in the root table
509    * in this case. The meta has HTableDescriptor serialized into the HRegionInfo;
510    * - version 0 is 0.92 and 0.94. Meta data has serialized HRegionInfo's using
511    * Writable serialization, and HRegionInfo's does not contain HTableDescriptors.
512    * - version 1 for 0.96+ keeps HRegionInfo data structures, but changes the
513    * byte[] serialization from Writables to Protobuf.
514    * See HRegionInfo.VERSION
515    */
516   public static final short META_VERSION = 1;
517 
518   // Other constants
519 
520   /**
521    * An empty instance.
522    */
523   public static final byte [] EMPTY_BYTE_ARRAY = new byte [0];
524 
525   /**
526    * Used by scanners, etc when they want to start at the beginning of a region
527    */
528   public static final byte [] EMPTY_START_ROW = EMPTY_BYTE_ARRAY;
529 
530   /**
531    * Last row in a table.
532    */
533   public static final byte [] EMPTY_END_ROW = EMPTY_START_ROW;
534 
535   /**
536     * Used by scanners and others when they're trying to detect the end of a
537     * table
538     */
539   public static final byte [] LAST_ROW = EMPTY_BYTE_ARRAY;
540 
541   /**
542    * Max length a row can have because of the limitation in TFile.
543    */
544   public static final int MAX_ROW_LENGTH = Short.MAX_VALUE;
545 
546   /**
547    * Timestamp to use when we want to refer to the latest cell.
548    * This is the timestamp sent by clients when no timestamp is specified on
549    * commit.
550    */
551   public static final long LATEST_TIMESTAMP = Long.MAX_VALUE;
552 
553   /**
554    * Timestamp to use when we want to refer to the oldest cell.
555    * Special! Used in fake Cells only. Should never be the timestamp on an actual Cell returned to
556    * a client.
557    * @deprecated Should not be public since hbase-1.3.0. For internal use only. Move internal to
558    * Scanners flagged as special timestamp value never to be returned as timestamp on a Cell.
559    */
560   @Deprecated
561   public static final long OLDEST_TIMESTAMP = Long.MIN_VALUE;
562 
563   /**
564    * LATEST_TIMESTAMP in bytes form
565    */
566   public static final byte [] LATEST_TIMESTAMP_BYTES = {
567     // big-endian
568     (byte) (LATEST_TIMESTAMP >>> 56),
569     (byte) (LATEST_TIMESTAMP >>> 48),
570     (byte) (LATEST_TIMESTAMP >>> 40),
571     (byte) (LATEST_TIMESTAMP >>> 32),
572     (byte) (LATEST_TIMESTAMP >>> 24),
573     (byte) (LATEST_TIMESTAMP >>> 16),
574     (byte) (LATEST_TIMESTAMP >>> 8),
575     (byte) LATEST_TIMESTAMP,
576   };
577 
578   /**
579    * Define for 'return-all-versions'.
580    */
581   public static final int ALL_VERSIONS = Integer.MAX_VALUE;
582 
583   /**
584    * Unlimited time-to-live.
585    */
586 //  public static final int FOREVER = -1;
587   public static final int FOREVER = Integer.MAX_VALUE;
588 
589   /**
590    * Seconds in a week
591    */
592   public static final int WEEK_IN_SECONDS = 7 * 24 * 3600;
593 
594   /**
595    * Seconds in a day, hour and minute
596    */
597   public static final int DAY_IN_SECONDS = 24 * 60 * 60;
598   public static final int HOUR_IN_SECONDS = 60 * 60;
599   public static final int MINUTE_IN_SECONDS = 60;
600 
601   //TODO: although the following are referenced widely to format strings for
602   //      the shell. They really aren't a part of the public API. It would be
603   //      nice if we could put them somewhere where they did not need to be
604   //      public. They could have package visibility
605   public static final String NAME = "NAME";
606   public static final String VERSIONS = "VERSIONS";
607   public static final String IN_MEMORY = "IN_MEMORY";
608   public static final String METADATA = "METADATA";
609   public static final String CONFIGURATION = "CONFIGURATION";
610 
611   /**
612    * Retrying we multiply hbase.client.pause setting by what we have in this array until we
613    * run out of array items.  Retries beyond this use the last number in the array.  So, for
614    * example, if hbase.client.pause is 1 second, and maximum retries count
615    * hbase.client.retries.number is 10, we will retry at the following intervals:
616    * 1, 2, 3, 5, 10, 20, 40, 100, 100, 100.
617    * With 100ms, a back-off of 200 means 20s
618    */
619   public static final int [] RETRY_BACKOFF = {1, 2, 3, 5, 10, 20, 40, 100, 100, 100, 100, 200, 200};
620 
621   public static final String REGION_IMPL = "hbase.hregion.impl";
622 
623   /** modifyTable op for replacing the table descriptor */
624   @InterfaceAudience.Private
625   public static enum Modify {
626     CLOSE_REGION,
627     TABLE_COMPACT,
628     TABLE_FLUSH,
629     TABLE_MAJOR_COMPACT,
630     TABLE_SET_HTD,
631     TABLE_SPLIT
632   }
633 
634   /**
635    * Scope tag for locally scoped data.
636    * This data will not be replicated.
637    */
638   public static final int REPLICATION_SCOPE_LOCAL = 0;
639 
640   /**
641    * Scope tag for globally scoped data.
642    * This data will be replicated to all peers.
643    */
644   public static final int REPLICATION_SCOPE_GLOBAL = 1;
645 
646   /**
647    * Default cluster ID, cannot be used to identify a cluster so a key with
648    * this value means it wasn't meant for replication.
649    */
650   public static final UUID DEFAULT_CLUSTER_ID = new UUID(0L,0L);
651 
652   /**
653    * Parameter name for maximum number of bytes returned when calling a scanner's next method.
654    * Controlled by the client.
655    */
656   public static final String HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE_KEY =
657       "hbase.client.scanner.max.result.size";
658 
659   /**
660    * Parameter name for maximum number of bytes returned when calling a scanner's next method.
661    * Controlled by the server.
662    */
663   public static final String HBASE_SERVER_SCANNER_MAX_RESULT_SIZE_KEY =
664       "hbase.server.scanner.max.result.size";
665 
666   /**
667    * Maximum number of bytes returned when calling a scanner's next method.
668    * Note that when a single row is larger than this limit the row is still
669    * returned completely.
670    *
671    * The default value is 2MB.
672    */
673   public static final long DEFAULT_HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE = 2 * 1024 * 1024;
674 
675   /**
676    * Maximum number of bytes returned when calling a scanner's next method.
677    * Note that when a single row is larger than this limit the row is still
678    * returned completely.
679    * Safety setting to protect the region server.
680    *
681    * The default value is 100MB. (a client would rarely request larger chunks on purpose)
682    */
683   public static final long DEFAULT_HBASE_SERVER_SCANNER_MAX_RESULT_SIZE = 100 * 1024 * 1024;
684 
685   /**
686    * Parameter name for client pause value, used mostly as value to wait
687    * before running a retry of a failed get, region lookup, etc.
688    */
689   public static final String HBASE_CLIENT_PAUSE = "hbase.client.pause";
690 
691   /**
692    * Default value of {@link #HBASE_CLIENT_PAUSE}.
693    */
694   public static final long DEFAULT_HBASE_CLIENT_PAUSE = 100;
695 
696   /*
697    * Parameter name for client pause value for special case such as call queue too big, etc.
698    */
699   public static final String HBASE_CLIENT_PAUSE_FOR_CQTBE = "hbase.client.pause.cqtbe";
700 
701   /**
702    * The maximum number of concurrent connections the client will maintain.
703    */
704   public static final String HBASE_CLIENT_MAX_TOTAL_TASKS = "hbase.client.max.total.tasks";
705 
706   /**
707    * Default value of {@link #HBASE_CLIENT_MAX_TOTAL_TASKS}.
708    */
709   public static final int DEFAULT_HBASE_CLIENT_MAX_TOTAL_TASKS = 100;
710 
711   /**
712    * The maximum number of concurrent connections the client will maintain to a single
713    * RegionServer.
714    */
715   public static final String HBASE_CLIENT_MAX_PERSERVER_TASKS = "hbase.client.max.perserver.tasks";
716 
717   /**
718    * Default value of {@link #HBASE_CLIENT_MAX_PERSERVER_TASKS}.
719    */
720   public static final int DEFAULT_HBASE_CLIENT_MAX_PERSERVER_TASKS = 2;
721 
722   /**
723    * The maximum number of concurrent connections the client will maintain to a single
724    * Region.
725    */
726   public static final String HBASE_CLIENT_MAX_PERREGION_TASKS = "hbase.client.max.perregion.tasks";
727 
728   /**
729    * Default value of {@link #HBASE_CLIENT_MAX_PERREGION_TASKS}.
730    */
731   public static final int DEFAULT_HBASE_CLIENT_MAX_PERREGION_TASKS = 1;
732 
733   /**
734    * The maximum number of concurrent pending RPC requests for one server in process level.
735    */
736   public static final String HBASE_CLIENT_PERSERVER_REQUESTS_THRESHOLD =
737       "hbase.client.perserver.requests.threshold";
738 
739   /**
740    * Default value of {@link #HBASE_CLIENT_PERSERVER_REQUESTS_THRESHOLD}.
741    */
742   public static final int DEFAULT_HBASE_CLIENT_PERSERVER_REQUESTS_THRESHOLD = Integer.MAX_VALUE;
743 
744 
745   /**
746    * Parameter name for server pause value, used mostly as value to wait before
747    * running a retry of a failed operation.
748    */
749   public static final String HBASE_SERVER_PAUSE = "hbase.server.pause";
750 
751   /**
752    * Default value of {@link #HBASE_SERVER_PAUSE}.
753    */
754   public static final int DEFAULT_HBASE_SERVER_PAUSE = 1000;
755 
756   /**
757    * Parameter name for maximum retries, used as maximum for all retryable
758    * operations such as fetching of the root region from root region server,
759    * getting a cell's value, starting a row update, etc.
760    */
761   public static final String HBASE_CLIENT_RETRIES_NUMBER = "hbase.client.retries.number";
762 
763   /**
764    * Default value of {@link #HBASE_CLIENT_RETRIES_NUMBER}.
765    */
766   public static final int DEFAULT_HBASE_CLIENT_RETRIES_NUMBER = 31;
767 
768   /**
769    * Parameter name to set the default scanner caching for all clients.
770    */
771   public static final String HBASE_CLIENT_SCANNER_CACHING = "hbase.client.scanner.caching";
772 
773   /**
774    * Default value for {@link #HBASE_CLIENT_SCANNER_CACHING}
775    */
776   public static final int DEFAULT_HBASE_CLIENT_SCANNER_CACHING = Integer.MAX_VALUE;
777 
778   /**
779    * Parameter name for number of versions, kept by meta table.
780    */
781   public static String HBASE_META_VERSIONS = "hbase.meta.versions";
782 
783   /**
784    * Default value of {@link #HBASE_META_VERSIONS}.
785    */
786   public static int DEFAULT_HBASE_META_VERSIONS = 3;
787 
788   /**
789    * Parameter name for number of versions, kept by meta table.
790    */
791   public static String HBASE_META_BLOCK_SIZE = "hbase.meta.blocksize";
792 
793   /**
794    * Default value of {@link #HBASE_META_BLOCK_SIZE}.
795    */
796   public static int DEFAULT_HBASE_META_BLOCK_SIZE = 8 * 1024;
797 
798   /**
799    * Parameter name for number of rows that will be fetched when calling next on
800    * a scanner if it is not served from memory. Higher caching values will
801    * enable faster scanners but will eat up more memory and some calls of next
802    * may take longer and longer times when the cache is empty.
803    */
804   public static final String HBASE_META_SCANNER_CACHING = "hbase.meta.scanner.caching";
805 
806   /**
807    * Default value of {@link #HBASE_META_SCANNER_CACHING}.
808    */
809   public static final int DEFAULT_HBASE_META_SCANNER_CACHING = 100;
810 
811   /**
812    * Parameter name for unique identifier for this {@link org.apache.hadoop.conf.Configuration}
813    * instance. If there are two or more {@link org.apache.hadoop.conf.Configuration} instances that,
814    * for all intents and purposes, are the same except for their instance ids, then they will not be
815    * able to share the same org.apache.hadoop.hbase.client.HConnection instance. On the other hand,
816    * even if the instance ids are the same, it could result in non-shared
817    * org.apache.hadoop.hbase.client.HConnection instances if some of the other connection parameters
818    * differ.
819    */
820   public static final String HBASE_CLIENT_INSTANCE_ID = "hbase.client.instance.id";
821 
822   /**
823    * The client scanner timeout period in milliseconds.
824    */
825   public static final String HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD = "hbase.client.scanner.timeout.period";
826 
827   /**
828    * Use {@link #HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD} instead.
829    * @deprecated This config option is deprecated. Will be removed at later releases after 0.96.
830    */
831   @Deprecated
832   public static final String HBASE_REGIONSERVER_LEASE_PERIOD_KEY =
833       "hbase.regionserver.lease.period";
834 
835   /**
836    * Default value of {@link #HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD}.
837    */
838   public static final int DEFAULT_HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD = 60000;
839 
840   /**
841    * timeout for each RPC
842    * @deprecated Use {@link #HBASE_RPC_READ_TIMEOUT_KEY} or {@link #HBASE_RPC_WRITE_TIMEOUT_KEY}
843    * instead.
844    */
845   @Deprecated
846   public static final String HBASE_RPC_TIMEOUT_KEY = "hbase.rpc.timeout";
847 
848   /**
849    * timeout for each read RPC
850    */
851   public static final String HBASE_RPC_READ_TIMEOUT_KEY = "hbase.rpc.read.timeout";
852 
853   /**
854    * timeout for each write RPC
855    */
856   public static final String HBASE_RPC_WRITE_TIMEOUT_KEY = "hbase.rpc.write.timeout";
857 
858   /**
859    * Default value of {@link #HBASE_RPC_TIMEOUT_KEY}
860    */
861   public static final int DEFAULT_HBASE_RPC_TIMEOUT = 60000;
862 
863   /**
864    * timeout for short operation RPC
865    */
866   public static final String HBASE_RPC_SHORTOPERATION_TIMEOUT_KEY =
867       "hbase.rpc.shortoperation.timeout";
868 
869   /**
870    * Default value of {@link #HBASE_RPC_SHORTOPERATION_TIMEOUT_KEY}
871    */
872   public static final int DEFAULT_HBASE_RPC_SHORTOPERATION_TIMEOUT = 10000;
873 
874   /**
875    * Value indicating the server name was saved with no sequence number.
876    */
877   public static final long NO_SEQNUM = -1;
878 
879 
880   /*
881    * cluster replication constants.
882    */
883   public static final String
884       REPLICATION_ENABLE_KEY = "hbase.replication";
885   public static final boolean
886       REPLICATION_ENABLE_DEFAULT = true;
887   public static final String
888       REPLICATION_SOURCE_SERVICE_CLASSNAME = "hbase.replication.source.service";
889   public static final String
890       REPLICATION_SINK_SERVICE_CLASSNAME = "hbase.replication.sink.service";
891   public static final String REPLICATION_SERVICE_CLASSNAME_DEFAULT =
892     "org.apache.hadoop.hbase.replication.regionserver.Replication";
893   public static final String REPLICATION_BULKLOAD_ENABLE_KEY = "hbase.replication.bulkload.enabled";
894   public static final boolean REPLICATION_BULKLOAD_ENABLE_DEFAULT = false;
895   /** Replication cluster id of source cluster which uniquely identifies itself with peer cluster */
896   public static final String REPLICATION_CLUSTER_ID = "hbase.replication.cluster.id";
897   /**
898    * Directory where the source cluster file system client configuration are placed which is used by
899    * sink cluster to copy HFiles from source cluster file system
900    */
901   public static final String REPLICATION_CONF_DIR = "hbase.replication.conf.dir";
902 
903   /** Maximum time to retry for a failed bulk load request */
904   public static final String BULKLOAD_MAX_RETRIES_NUMBER = "hbase.bulkload.retries.number";
905 
906   /** HBCK special code name used as server name when manipulating ZK nodes */
907   public static final String HBCK_CODE_NAME = "HBCKServerName";
908 
909   public static final String KEY_FOR_HOSTNAME_SEEN_BY_MASTER =
910     "hbase.regionserver.hostname.seen.by.master";
911 
912   public static final String HBASE_MASTER_LOGCLEANER_PLUGINS =
913       "hbase.master.logcleaner.plugins";
914 
915   public static final String HBASE_REGION_SPLIT_POLICY_KEY =
916     "hbase.regionserver.region.split.policy";
917 
918   /** Whether nonces are enabled; default is true. */
919   public static final String HBASE_RS_NONCES_ENABLED = "hbase.regionserver.nonces.enabled";
920 
921   /**
922    * Configuration key for the size of the block cache
923    */
924   public static final String HFILE_BLOCK_CACHE_SIZE_KEY =
925     "hfile.block.cache.size";
926 
927   public static final float HFILE_BLOCK_CACHE_SIZE_DEFAULT = 0.4f;
928 
929   /*
930     * Minimum percentage of free heap necessary for a successful cluster startup.
931     */
932   public static final float HBASE_CLUSTER_MINIMUM_MEMORY_THRESHOLD = 0.2f;
933 
934   public static final Pattern CP_HTD_ATTR_KEY_PATTERN =
935       Pattern.compile("^coprocessor\\$([0-9]+)$", Pattern.CASE_INSENSITIVE);
936 
937   /**
938    * Pattern that matches a coprocessor specification. Form is:
939    * <code>
940    *&lt;coprocessor jar file location> '|' &lt<class name> ['|' &lt;priority> ['|' &lt;arguments>]]
941    * </code>
942    * ...where arguments are <code>&lt;KEY> '=' &lt;VALUE> [,...]</code>
943    * <p>For example: <code>hdfs:///foo.jar|com.foo.FooRegionObserver|1001|arg1=1,arg2=2</code>
944    */
945   public static final Pattern CP_HTD_ATTR_VALUE_PATTERN =
946       Pattern.compile("(^[^\\|]*)\\|([^\\|]+)\\|[\\s]*([\\d]*)[\\s]*(\\|.*)?$");
947 
948   public static final String CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN = "[^=,]+";
949   public static final String CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN = "[^,]+";
950   public static final Pattern CP_HTD_ATTR_VALUE_PARAM_PATTERN = Pattern.compile(
951       "(" + CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN + ")=(" +
952       CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN + "),?");
953   public static final String CP_HTD_ATTR_INCLUSION_KEY =
954       "hbase.coprocessor.classloader.included.classes";
955 
956   /** The delay when re-trying a socket operation in a loop (HBASE-4712) */
957   public static final int SOCKET_RETRY_WAIT_MS = 200;
958 
959   /** Host name of the local machine */
960   public static final String LOCALHOST = "localhost";
961 
962   /**
963    * If this parameter is set to true, then hbase will read
964    * data and then verify checksums. Checksum verification
965    * inside hdfs will be switched off.  However, if the hbase-checksum
966    * verification fails, then it will switch back to using
967    * hdfs checksums for verifiying data that is being read from storage.
968    *
969    * If this parameter is set to false, then hbase will not
970    * verify any checksums, instead it will depend on checksum verification
971    * being done in the hdfs client.
972    */
973   public static final String HBASE_CHECKSUM_VERIFICATION =
974       "hbase.regionserver.checksum.verify";
975 
976   public static final String LOCALHOST_IP = "127.0.0.1";
977 
978   /** Conf key that enables unflushed WAL edits directly being replayed to region servers
979    */
980   public static final String DISTRIBUTED_LOG_REPLAY_KEY = "hbase.master.distributed.log.replay";
981   public static final boolean DEFAULT_DISTRIBUTED_LOG_REPLAY_CONFIG = false;
982   public static final String DISALLOW_WRITES_IN_RECOVERING =
983       "hbase.regionserver.disallow.writes.when.recovering";
984   public static final boolean DEFAULT_DISALLOW_WRITES_IN_RECOVERING_CONFIG = false;
985 
986   public static final String REGION_SERVER_HANDLER_COUNT = "hbase.regionserver.handler.count";
987   public static final int DEFAULT_REGION_SERVER_HANDLER_COUNT = 30;
988 
989   /*
990    * REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT:
991    * -1  => Disable aborting
992    * 0   => Abort if even a single handler has died
993    * 0.x => Abort only when this percent of handlers have died
994    * 1   => Abort only all of the handers have died
995    */
996   public static final String REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT =
997       "hbase.regionserver.handler.abort.on.error.percent";
998   public static final double DEFAULT_REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT = 0.5;
999 
1000   //High priority handlers to deal with admin requests and system table operation requests
1001   public static final String REGION_SERVER_HIGH_PRIORITY_HANDLER_COUNT =
1002       "hbase.regionserver.metahandler.count";
1003   public static final int DEFAULT_REGION_SERVER_HIGH_PRIORITY_HANDLER_COUNT = 20;
1004 
1005   public static final String REGION_SERVER_REPLICATION_HANDLER_COUNT =
1006       "hbase.regionserver.replication.handler.count";
1007   public static final int DEFAULT_REGION_SERVER_REPLICATION_HANDLER_COUNT = 3;
1008 
1009   public static final String MASTER_HANDLER_COUNT = "hbase.master.handler.count";
1010   public static final int DEFAULT_MASTER_HANLDER_COUNT = 25;
1011 
1012   /** Conf key that specifies timeout value to wait for a region ready */
1013   public static final String LOG_REPLAY_WAIT_REGION_TIMEOUT =
1014       "hbase.master.log.replay.wait.region.timeout";
1015 
1016   /** Conf key for enabling meta replication */
1017   public static final String USE_META_REPLICAS = "hbase.meta.replicas.use";
1018   public static final boolean DEFAULT_USE_META_REPLICAS = false;
1019   public static final String META_REPLICAS_NUM = "hbase.meta.replica.count";
1020   public static final int DEFAULT_META_REPLICA_NUM = 1;
1021 
1022   /**
1023    * The name of the configuration parameter that specifies
1024    * the number of bytes in a newly created checksum chunk.
1025    */
1026   public static final String BYTES_PER_CHECKSUM =
1027       "hbase.hstore.bytes.per.checksum";
1028 
1029   /**
1030    * The name of the configuration parameter that specifies
1031    * the name of an algorithm that is used to compute checksums
1032    * for newly created blocks.
1033    */
1034   public static final String CHECKSUM_TYPE_NAME =
1035       "hbase.hstore.checksum.algorithm";
1036 
1037   /** Enable file permission modification from standard hbase */
1038   public static final String ENABLE_DATA_FILE_UMASK = "hbase.data.umask.enable";
1039   /** File permission umask to use when creating hbase data files */
1040   public static final String DATA_FILE_UMASK_KEY = "hbase.data.umask";
1041 
1042   /** Configuration name of WAL Compression */
1043   public static final String ENABLE_WAL_COMPRESSION =
1044     "hbase.regionserver.wal.enablecompression";
1045 
1046   /** Configuration name of WAL storage policy
1047    * Valid values are:
1048    *  NONE: no preference in destination of block replicas
1049    *  ONE_SSD: place only one block replica in SSD and the remaining in default storage
1050    *  and ALL_SSD: place all block replicas on SSD
1051    *
1052    * See http://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/hadoop-hdfs/ArchivalStorage.html*/
1053   public static final String WAL_STORAGE_POLICY = "hbase.wal.storage.policy";
1054   public static final String DEFAULT_WAL_STORAGE_POLICY = "NONE";
1055 
1056   /** Region in Transition metrics threshold time */
1057   public static final String METRICS_RIT_STUCK_WARNING_THRESHOLD =
1058       "hbase.metrics.rit.stuck.warning.threshold";
1059 
1060   public static final String LOAD_BALANCER_SLOP_KEY = "hbase.regions.slop";
1061 
1062   /** delimiter used between portions of a region name */
1063   public static final int DELIMITER = ',';
1064   public static final String HBASE_CONFIG_READ_ZOOKEEPER_CONFIG =
1065       "hbase.config.read.zookeeper.config";
1066   public static final boolean DEFAULT_HBASE_CONFIG_READ_ZOOKEEPER_CONFIG =
1067       false;
1068 
1069   /**
1070    * QOS attributes: these attributes are used to demarcate RPC call processing
1071    * by different set of handlers. For example, HIGH_QOS tagged methods are
1072    * handled by high priority handlers.
1073    */
1074   // normal_QOS < QOS_threshold < replication_QOS < replay_QOS < admin_QOS < high_QOS
1075   public static final int PRIORITY_UNSET = -1;
1076   public static final int NORMAL_QOS = 0;
1077   public static final int QOS_THRESHOLD = 10;
1078   public static final int HIGH_QOS = 200;
1079   public static final int REPLICATION_QOS = 5;
1080   public static final int REPLAY_QOS = 6;
1081   public static final int ADMIN_QOS = 100;
1082   public static final int SYSTEMTABLE_QOS = HIGH_QOS;
1083 
1084   /** Directory under /hbase where archived hfiles are stored */
1085   public static final String HFILE_ARCHIVE_DIRECTORY = "archive";
1086 
1087   /**
1088    * Name of the directory to store all snapshots. See SnapshotDescriptionUtils for
1089    * remaining snapshot constants; this is here to keep HConstants dependencies at a minimum and
1090    * uni-directional.
1091    */
1092   public static final String SNAPSHOT_DIR_NAME = ".hbase-snapshot";
1093 
1094   /* Name of old snapshot directory. See HBASE-8352 for details on why it needs to be renamed */
1095   public static final String OLD_SNAPSHOT_DIR_NAME = ".snapshot";
1096 
1097   /** Temporary directory used for table creation and deletion */
1098   public static final String HBASE_TEMP_DIRECTORY = ".tmp";
1099   /**
1100    * The period (in milliseconds) between computing region server point in time metrics
1101    */
1102   public static final String REGIONSERVER_METRICS_PERIOD = "hbase.regionserver.metrics.period";
1103   public static final long DEFAULT_REGIONSERVER_METRICS_PERIOD = 5000;
1104   /** Directories that are not HBase table directories */
1105   public static final List<String> HBASE_NON_TABLE_DIRS =
1106     Collections.unmodifiableList(Arrays.asList(new String[] {
1107       HBCK_SIDELINEDIR_NAME, HBASE_TEMP_DIRECTORY, MIGRATION_NAME
1108     }));
1109 
1110   /** Directories that are not HBase user table directories */
1111   public static final List<String> HBASE_NON_USER_TABLE_DIRS =
1112     Collections.unmodifiableList(Arrays.asList((String[])ArrayUtils.addAll(
1113       new String[] { TableName.META_TABLE_NAME.getNameAsString() },
1114       HBASE_NON_TABLE_DIRS.toArray())));
1115 
1116   /** Health script related settings. */
1117   public static final String HEALTH_SCRIPT_LOC = "hbase.node.health.script.location";
1118   public static final String HEALTH_SCRIPT_TIMEOUT = "hbase.node.health.script.timeout";
1119   public static final String HEALTH_CHORE_WAKE_FREQ =
1120       "hbase.node.health.script.frequency";
1121   public static final long DEFAULT_HEALTH_SCRIPT_TIMEOUT = 60000;
1122   /**
1123    * The maximum number of health check failures a server can encounter consecutively.
1124    */
1125   public static final String HEALTH_FAILURE_THRESHOLD =
1126       "hbase.node.health.failure.threshold";
1127   public static final int DEFAULT_HEALTH_FAILURE_THRESHOLD = 3;
1128 
1129 
1130   /**
1131    * Setting to activate, or not, the publication of the status by the master. Default
1132    *  notification is by a multicast message.
1133    */
1134   public static final String STATUS_PUBLISHED = "hbase.status.published";
1135   public static final boolean STATUS_PUBLISHED_DEFAULT = false;
1136 
1137   /**
1138    * IP to use for the multicast status messages between the master and the clients.
1139    * The default address is chosen as one among others within the ones suitable for multicast
1140    * messages.
1141    */
1142   public static final String STATUS_MULTICAST_ADDRESS = "hbase.status.multicast.address.ip";
1143   public static final String DEFAULT_STATUS_MULTICAST_ADDRESS = "226.1.1.3";
1144 
1145   /**
1146    * The address to use for binding the local socket for receiving multicast. Defaults to
1147    * 0.0.0.0.
1148    * @see <a href="https://issues.apache.org/jira/browse/HBASE-9961">HBASE-9961</a>
1149    */
1150   public static final String STATUS_MULTICAST_BIND_ADDRESS =
1151       "hbase.status.multicast.bind.address.ip";
1152   public static final String DEFAULT_STATUS_MULTICAST_BIND_ADDRESS = "0.0.0.0";
1153 
1154   /**
1155    * The port to use for the multicast messages.
1156    */
1157   public static final String STATUS_MULTICAST_PORT = "hbase.status.multicast.address.port";
1158   public static final int DEFAULT_STATUS_MULTICAST_PORT = 16100;
1159 
1160   public static final long NO_NONCE = 0;
1161 
1162   /** Default cipher for encryption */
1163   public static final String CIPHER_AES = "AES";
1164 
1165   /** Configuration key for the crypto algorithm provider, a class name */
1166   public static final String CRYPTO_CIPHERPROVIDER_CONF_KEY = "hbase.crypto.cipherprovider";
1167 
1168   /** Configuration key for the crypto key provider, a class name */
1169   public static final String CRYPTO_KEYPROVIDER_CONF_KEY = "hbase.crypto.keyprovider";
1170 
1171   /** Configuration key for the crypto key provider parameters */
1172   public static final String CRYPTO_KEYPROVIDER_PARAMETERS_KEY =
1173       "hbase.crypto.keyprovider.parameters";
1174 
1175   /** Configuration key for the name of the master key for the cluster, a string */
1176   public static final String CRYPTO_MASTERKEY_NAME_CONF_KEY = "hbase.crypto.master.key.name";
1177 
1178   /** Configuration key for the name of the alternate master key for the cluster, a string */
1179   public static final String CRYPTO_MASTERKEY_ALTERNATE_NAME_CONF_KEY =
1180     "hbase.crypto.master.alternate.key.name";
1181 
1182   /** Configuration key for the algorithm to use when encrypting the WAL, a string */
1183   public static final String CRYPTO_WAL_ALGORITHM_CONF_KEY = "hbase.crypto.wal.algorithm";
1184 
1185   /** Configuration key for the name of the master WAL encryption key for the cluster, a string */
1186   public static final String CRYPTO_WAL_KEY_NAME_CONF_KEY = "hbase.crypto.wal.key.name";
1187 
1188   /** Configuration key for the algorithm used for creating jks key, a string */
1189   public static final String CRYPTO_KEY_ALGORITHM_CONF_KEY = "hbase.crypto.key.algorithm";
1190 
1191   /** Configuration key for the name of the alternate cipher algorithm for the cluster, a string */
1192   public static final String CRYPTO_ALTERNATE_KEY_ALGORITHM_CONF_KEY =
1193       "hbase.crypto.alternate.key.algorithm";
1194 
1195   /** Configuration key for enabling WAL encryption, a boolean */
1196   public static final String ENABLE_WAL_ENCRYPTION = "hbase.regionserver.wal.encryption";
1197 
1198   /** Configuration key for setting RPC codec class name */
1199   public static final String RPC_CODEC_CONF_KEY = "hbase.client.rpc.codec";
1200 
1201   /** Configuration key for setting replication codec class name */
1202   public static final String REPLICATION_CODEC_CONF_KEY = "hbase.replication.rpc.codec";
1203 
1204   /** Maximum number of threads used by the replication source for shipping edits to the sinks */
1205   public static final String REPLICATION_SOURCE_MAXTHREADS_KEY =
1206       "hbase.replication.source.maxthreads";
1207 
1208   /** Drop edits for tables that been deleted from the replication source and target */
1209   public static final String REPLICATION_DROP_ON_DELETED_TABLE_KEY =
1210       "hbase.replication.drop.on.deleted.table";
1211 
1212   /** Maximum number of threads used by the replication source for shipping edits to the sinks */
1213   public static final int REPLICATION_SOURCE_MAXTHREADS_DEFAULT = 10;
1214 
1215   /** Config for pluggable consensus provider */
1216   public static final String HBASE_COORDINATED_STATE_MANAGER_CLASS =
1217     "hbase.coordinated.state.manager.class";
1218 
1219   /** Configuration key for SplitLog manager timeout */
1220   public static final String HBASE_SPLITLOG_MANAGER_TIMEOUT = "hbase.splitlog.manager.timeout";
1221 
1222   /**
1223    * Configuration keys for Bucket cache
1224    */
1225   // TODO moving these bucket cache implementation specific configs to this level is violation of
1226   // encapsulation. But as these has to be referred from hbase-common and bucket cache
1227   // sits in hbase-server, there were no other go! Can we move the cache implementation to
1228   // hbase-common?
1229 
1230   /**
1231    * Current ioengine options in include: heap, offheap and file:PATH (where PATH is the path
1232    * to the file that will host the file-based cache.  See BucketCache#getIOEngineFromName() for
1233    * list of supported ioengine options.
1234    * <p>Set this option and a non-zero {@link #BUCKET_CACHE_SIZE_KEY} to enable bucket cache.
1235    */
1236   public static final String BUCKET_CACHE_IOENGINE_KEY = "hbase.bucketcache.ioengine";
1237 
1238   /**
1239    * When using bucket cache, this is a float that EITHER represents a percentage of total heap
1240    * memory size to give to the cache (if &lt; 1.0) OR, it is the capacity in
1241    * megabytes of the cache.
1242    */
1243   public static final String BUCKET_CACHE_SIZE_KEY = "hbase.bucketcache.size";
1244 
1245   /**
1246    * HConstants for fast fail on the client side follow
1247    */
1248   /**
1249    * Config for enabling/disabling the fast fail mode.
1250    */
1251   public static final String HBASE_CLIENT_FAST_FAIL_MODE_ENABLED =
1252       "hbase.client.fast.fail.mode.enabled";
1253 
1254   public static final boolean HBASE_CLIENT_ENABLE_FAST_FAIL_MODE_DEFAULT =
1255       false;
1256 
1257   public static final String HBASE_CLIENT_FAST_FAIL_THREASHOLD_MS =
1258       "hbase.client.fastfail.threshold";
1259 
1260   public static final long HBASE_CLIENT_FAST_FAIL_THREASHOLD_MS_DEFAULT =
1261       60000;
1262 
1263   public static final String HBASE_CLIENT_FAST_FAIL_CLEANUP_MS_DURATION_MS =
1264       "hbase.client.fast.fail.cleanup.duration";
1265 
1266   public static final long HBASE_CLIENT_FAST_FAIL_CLEANUP_DURATION_MS_DEFAULT =
1267       600000;
1268 
1269   public static final String HBASE_CLIENT_FAST_FAIL_INTERCEPTOR_IMPL =
1270       "hbase.client.fast.fail.interceptor.impl";
1271 
1272   /** Config key for if the server should send backpressure and if the client should listen to
1273    * that backpressure from the server */
1274   public static final String ENABLE_CLIENT_BACKPRESSURE = "hbase.client.backpressure.enabled";
1275   public static final boolean DEFAULT_ENABLE_CLIENT_BACKPRESSURE = false;
1276 
1277   public static final String HEAP_OCCUPANCY_LOW_WATERMARK_KEY =
1278       "hbase.heap.occupancy.low_water_mark";
1279   public static final float DEFAULT_HEAP_OCCUPANCY_LOW_WATERMARK = 0.95f;
1280   public static final String HEAP_OCCUPANCY_HIGH_WATERMARK_KEY =
1281       "hbase.heap.occupancy.high_water_mark";
1282   public static final float DEFAULT_HEAP_OCCUPANCY_HIGH_WATERMARK = 0.98f;
1283 
1284   /**
1285    * The max number of threads used for splitting storefiles in parallel during
1286    * the region split process.
1287    */
1288   public static final String REGION_SPLIT_THREADS_MAX =
1289     "hbase.regionserver.region.split.threads.max";
1290 
1291   /** Canary config keys */
1292   public static final String HBASE_CANARY_WRITE_DATA_TTL_KEY = "hbase.canary.write.data.ttl";
1293 
1294   public static final String HBASE_CANARY_WRITE_PERSERVER_REGIONS_LOWERLIMIT_KEY =
1295       "hbase.canary.write.perserver.regions.lowerLimit";
1296 
1297   public static final String HBASE_CANARY_WRITE_PERSERVER_REGIONS_UPPERLIMIT_KEY =
1298       "hbase.canary.write.perserver.regions.upperLimit";
1299 
1300   public static final String HBASE_CANARY_WRITE_VALUE_SIZE_KEY = "hbase.canary.write.value.size";
1301 
1302   public static final String HBASE_CANARY_WRITE_TABLE_CHECK_PERIOD_KEY =
1303       "hbase.canary.write.table.check.period";
1304   
1305   public static final String HBASE_CANARY_READ_RAW_SCAN_KEY = "hbase.canary.read.raw.enabled";
1306 
1307   /**
1308    * Configuration keys for programmatic JAAS configuration for secured ZK interaction
1309    */
1310   public static final String ZK_CLIENT_KEYTAB_FILE = "hbase.zookeeper.client.keytab.file";
1311   public static final String ZK_CLIENT_KERBEROS_PRINCIPAL =
1312       "hbase.zookeeper.client.kerberos.principal";
1313   public static final String ZK_SERVER_KEYTAB_FILE = "hbase.zookeeper.server.keytab.file";
1314   public static final String ZK_SERVER_KERBEROS_PRINCIPAL =
1315       "hbase.zookeeper.server.kerberos.principal";
1316 
1317   /** Config key for hbase temporary directory in hdfs */
1318   public static final String TEMPORARY_FS_DIRECTORY_KEY = "hbase.fs.tmp.dir";
1319   public static final String DEFAULT_TEMPORARY_HDFS_DIRECTORY = "/user/"
1320       + System.getProperty("user.name") + "/hbase-staging";
1321   public static final String DEFAULT_LOSSY_COUNTING_ERROR_RATE =
1322       "hbase.util.default.lossycounting.errorrate";
1323   private HConstants() {
1324     // Can't be instantiated with this ctor.
1325   }
1326 }