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