001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase;
019
020import static org.apache.hadoop.hbase.io.hfile.BlockType.MAGIC_LENGTH;
021
022import java.nio.ByteBuffer;
023import java.nio.charset.Charset;
024import java.util.Arrays;
025import java.util.Collections;
026import java.util.List;
027import java.util.UUID;
028import java.util.regex.Pattern;
029
030import org.apache.commons.lang3.ArrayUtils;
031import org.apache.hadoop.hbase.util.Bytes;
032import org.apache.yetus.audience.InterfaceAudience;
033
034/**
035 * HConstants holds a bunch of HBase-related constants
036 */
037@InterfaceAudience.Public
038public final class HConstants {
039  // NOTICE!!!! Please do not add a constants here, unless they are referenced by a lot of classes.
040
041  //Bytes.UTF8_ENCODING should be updated if this changed
042  /** When we encode strings, we always specify UTF8 encoding */
043  public static final String UTF8_ENCODING = "UTF-8";
044
045  //Bytes.UTF8_CHARSET should be updated if this changed
046  /** When we encode strings, we always specify UTF8 encoding */
047  public static final Charset UTF8_CHARSET = Charset.forName(UTF8_ENCODING);
048  /**
049   * Default block size for an HFile.
050   */
051  public final static int DEFAULT_BLOCKSIZE = 64 * 1024;
052
053  /** Used as a magic return value while optimized index key feature enabled(HBASE-7845) */
054  public final static int INDEX_KEY_MAGIC = -2;
055  /*
056     * Name of directory that holds recovered edits written by the wal log
057     * splitting code, one per region
058     */
059  public static final String RECOVERED_EDITS_DIR = "recovered.edits";
060  /**
061   * The first four bytes of Hadoop RPC connections
062   */
063  public static final byte[] RPC_HEADER = new byte[] { 'H', 'B', 'a', 's' };
064  public static final byte RPC_CURRENT_VERSION = 0;
065
066  // HFileBlock constants. TODO!!!! THESE DEFINES BELONG IN HFILEBLOCK, NOT UP HERE.
067  // Needed down in hbase-common though by encoders but these encoders should not be dealing
068  // in the internals of hfileblocks. Fix encapsulation.
069
070  /** The size data structures with minor version is 0 */
071  public static final int HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM = MAGIC_LENGTH + 2 * Bytes.SIZEOF_INT
072      + Bytes.SIZEOF_LONG;
073  /** The size of a version 2 HFile block header, minor version 1.
074   * There is a 1 byte checksum type, followed by a 4 byte bytesPerChecksum
075   * followed by another 4 byte value to store sizeofDataOnDisk.
076   */
077  public static final int HFILEBLOCK_HEADER_SIZE = HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM +
078    Bytes.SIZEOF_BYTE + 2 * Bytes.SIZEOF_INT;
079  /** Just an array of bytes of the right size. */
080  public static final byte[] HFILEBLOCK_DUMMY_HEADER = new byte[HFILEBLOCK_HEADER_SIZE];
081
082  //End HFileBlockConstants.
083
084  /**
085   * Status codes used for return values of bulk operations.
086   */
087  @InterfaceAudience.Private
088  public enum OperationStatusCode {
089    NOT_RUN,
090    SUCCESS,
091    BAD_FAMILY,
092    SANITY_CHECK_FAILURE,
093    FAILURE
094  }
095
096  /** long constant for zero */
097  public static final Long ZERO_L = Long.valueOf(0L);
098  public static final String NINES = "99999999999999";
099  public static final String ZEROES = "00000000000000";
100
101  // For migration
102
103  /** name of version file */
104  public static final String VERSION_FILE_NAME = "hbase.version";
105
106  /**
107   * Current version of file system.
108   * Version 4 supports only one kind of bloom filter.
109   * Version 5 changes versions in catalog table regions.
110   * Version 6 enables blockcaching on catalog tables.
111   * Version 7 introduces hfile -- hbase 0.19 to 0.20..
112   * Version 8 introduces namespace
113   */
114  // public static final String FILE_SYSTEM_VERSION = "6";
115  public static final String FILE_SYSTEM_VERSION = "8";
116
117  // Configuration parameters
118
119  //TODO: Is having HBase homed on port 60k OK?
120
121  /** Cluster is in distributed mode or not */
122  public static final String CLUSTER_DISTRIBUTED = "hbase.cluster.distributed";
123
124  /** Config for pluggable load balancers */
125  public static final String HBASE_MASTER_LOADBALANCER_CLASS = "hbase.master.loadbalancer.class";
126
127  /** Config for balancing the cluster by table */
128  public static final String HBASE_MASTER_LOADBALANCE_BYTABLE = "hbase.master.loadbalance.bytable";
129
130  /** Config for the max percent of regions in transition */
131  public static final String HBASE_MASTER_BALANCER_MAX_RIT_PERCENT =
132      "hbase.master.balancer.maxRitPercent";
133
134  /** Default value for the max percent of regions in transition */
135  public static final double DEFAULT_HBASE_MASTER_BALANCER_MAX_RIT_PERCENT = 1.0;
136
137  /** Config for the max balancing time */
138  public static final String HBASE_BALANCER_MAX_BALANCING = "hbase.balancer.max.balancing";
139
140  /** Config for the balancer period */
141  public static final String HBASE_BALANCER_PERIOD = "hbase.balancer.period";
142
143  /** Default value for the balancer period */
144  public static final int DEFAULT_HBASE_BALANCER_PERIOD = 300000;
145
146  /** The name of the ensemble table */
147  public static final TableName ENSEMBLE_TABLE_NAME = TableName.valueOf("hbase:ensemble");
148
149  /** Config for pluggable region normalizer */
150  public static final String HBASE_MASTER_NORMALIZER_CLASS =
151    "hbase.master.normalizer.class";
152
153  /** Cluster is standalone or pseudo-distributed */
154  public static final boolean CLUSTER_IS_LOCAL = false;
155
156  /** Cluster is fully-distributed */
157  @Deprecated // unused. see HBASE-13636. remove this in 3.0
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  /**
182   * by default every master is a possible primary master unless the conf explicitly overrides it
183   */
184  public static final boolean DEFAULT_MASTER_TYPE_BACKUP = false;
185
186  /** Name of ZooKeeper quorum configuration parameter. */
187  public static final String ZOOKEEPER_QUORUM = "hbase.zookeeper.quorum";
188
189  /** Common prefix of ZooKeeper configuration properties */
190  public static final String ZK_CFG_PROPERTY_PREFIX =
191      "hbase.zookeeper.property.";
192
193  public static final int ZK_CFG_PROPERTY_PREFIX_LEN =
194      ZK_CFG_PROPERTY_PREFIX.length();
195
196  /**
197   * The ZK client port key in the ZK properties map. The name reflects the
198   * fact that this is not an HBase configuration key.
199   */
200  public static final String CLIENT_PORT_STR = "clientPort";
201
202  /** Parameter name for the client port that the zookeeper listens on */
203  public static final String ZOOKEEPER_CLIENT_PORT =
204      ZK_CFG_PROPERTY_PREFIX + CLIENT_PORT_STR;
205
206  /** Default client port that the zookeeper listens on */
207  public static final int DEFAULT_ZOOKEPER_CLIENT_PORT = 2181;
208
209  /**
210   * Parameter name for the wait time for the recoverable zookeeper
211   */
212  @Deprecated // unused. see HBASE-3065. remove this in 3.0
213  public static final String ZOOKEEPER_RECOVERABLE_WAITTIME =
214      "hbase.zookeeper.recoverable.waittime";
215
216  /** Default wait time for the recoverable zookeeper */
217  @Deprecated // unused. see HBASE-3065. remove this in 3.0
218  public static final long DEFAULT_ZOOKEPER_RECOVERABLE_WAITIME = 10000;
219
220  /** Parameter name for the root dir in ZK for this cluster */
221  public static final String ZOOKEEPER_ZNODE_PARENT = "zookeeper.znode.parent";
222
223  public static final String DEFAULT_ZOOKEEPER_ZNODE_PARENT = "/hbase";
224
225  /**
226   * Parameter name for the limit on concurrent client-side zookeeper
227   * connections
228   */
229  public static final String ZOOKEEPER_MAX_CLIENT_CNXNS =
230      ZK_CFG_PROPERTY_PREFIX + "maxClientCnxns";
231
232  /** Parameter name for the ZK data directory */
233  public static final String ZOOKEEPER_DATA_DIR =
234      ZK_CFG_PROPERTY_PREFIX + "dataDir";
235
236  /** Parameter name for the ZK tick time */
237  public static final String ZOOKEEPER_TICK_TIME =
238      ZK_CFG_PROPERTY_PREFIX + "tickTime";
239
240  /** Default limit on concurrent client-side zookeeper connections */
241  public static final int DEFAULT_ZOOKEPER_MAX_CLIENT_CNXNS = 300;
242
243  /** Configuration key for ZooKeeper session timeout */
244  public static final String ZK_SESSION_TIMEOUT = "zookeeper.session.timeout";
245
246  /** Default value for ZooKeeper session timeout */
247  public static final int DEFAULT_ZK_SESSION_TIMEOUT = 90 * 1000;
248
249  /** Parameter name for port region server listens on. */
250  public static final String REGIONSERVER_PORT = "hbase.regionserver.port";
251
252  /** Default port region server listens on. */
253  public static final int DEFAULT_REGIONSERVER_PORT = 16020;
254
255  /** default port for region server web api */
256  public static final int DEFAULT_REGIONSERVER_INFOPORT = 16030;
257
258  /** A configuration key for regionserver info port */
259  public static final String REGIONSERVER_INFO_PORT =
260    "hbase.regionserver.info.port";
261
262  /** A flag that enables automatic selection of regionserver info port */
263  public static final String REGIONSERVER_INFO_PORT_AUTO =
264      REGIONSERVER_INFO_PORT + ".auto";
265
266  /** Parameter name for what region server implementation to use. */
267  public static final String REGION_SERVER_IMPL= "hbase.regionserver.impl";
268
269  /** Parameter name for what master implementation to use. */
270  public static final String MASTER_IMPL= "hbase.master.impl";
271
272  /** Parameter name for what hbase client implementation to use. */
273  @Deprecated // unused. see HBASE-7460. remove this in 3.0
274  public static final String HBASECLIENT_IMPL= "hbase.hbaseclient.impl";
275
276  /** Parameter name for how often threads should wake up */
277  public static final String THREAD_WAKE_FREQUENCY = "hbase.server.thread.wakefrequency";
278
279  /** Default value for thread wake frequency */
280  public static final int DEFAULT_THREAD_WAKE_FREQUENCY = 10 * 1000;
281
282  /** Parameter name for how often we should try to write a version file, before failing */
283  public static final String VERSION_FILE_WRITE_ATTEMPTS = "hbase.server.versionfile.writeattempts";
284
285  /** Parameter name for how often we should try to write a version file, before failing */
286  public static final int DEFAULT_VERSION_FILE_WRITE_ATTEMPTS = 3;
287
288  /** Parameter name and default value for how often a region should perform a major compaction */
289  public static final String MAJOR_COMPACTION_PERIOD = "hbase.hregion.majorcompaction";
290  public static final long   DEFAULT_MAJOR_COMPACTION_PERIOD = 1000 * 60 * 60 * 24 * 7; // 7 days
291
292  /**
293   * Parameter name and default value for major compaction jitter.
294   * Used as a multiplier applied to {@link HConstants#MAJOR_COMPACTION_PERIOD}
295   * to cause compaction to occur a given amount of time either side of
296   * {@link HConstants#MAJOR_COMPACTION_PERIOD}.
297   * Default to 0.5 so jitter has us fall evenly either side of when the compaction should run.
298   */
299  public static final String MAJOR_COMPACTION_JITTER = "hbase.hregion.majorcompaction.jitter";
300  public static final float  DEFAULT_MAJOR_COMPACTION_JITTER = 0.50F;
301
302  /** Parameter name for the maximum batch of KVs to be used in flushes and compactions */
303  public static final String COMPACTION_KV_MAX = "hbase.hstore.compaction.kv.max";
304  public static final int COMPACTION_KV_MAX_DEFAULT = 10;
305
306  /** Parameter name for HBase instance root directory */
307  public static final String HBASE_DIR = "hbase.rootdir";
308
309  /** Parameter name for HBase client IPC pool type */
310  public static final String HBASE_CLIENT_IPC_POOL_TYPE = "hbase.client.ipc.pool.type";
311
312  /** Parameter name for HBase client IPC pool size */
313  public static final String HBASE_CLIENT_IPC_POOL_SIZE = "hbase.client.ipc.pool.size";
314
315  /** Parameter name for HBase client operation timeout. */
316  public static final String HBASE_CLIENT_OPERATION_TIMEOUT = "hbase.client.operation.timeout";
317
318  /** Parameter name for HBase client operation timeout. */
319  public static final String HBASE_CLIENT_META_OPERATION_TIMEOUT =
320    "hbase.client.meta.operation.timeout";
321
322  /** Default HBase client operation timeout, which is tantamount to a blocking call */
323  public static final int DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT = 1200000;
324
325  /** Parameter name for HBase client meta replica scan call timeout. */
326  public static final String HBASE_CLIENT_META_REPLICA_SCAN_TIMEOUT =
327      "hbase.client.meta.replica.scan.timeout";
328
329  /** Default HBase client meta replica scan call timeout, 1 second */
330  public static final int HBASE_CLIENT_META_REPLICA_SCAN_TIMEOUT_DEFAULT = 1000000;
331
332  /** Used to construct the name of the log directory for a region server */
333  public static final String HREGION_LOGDIR_NAME = "WALs";
334
335  /** Used to construct the name of the splitlog directory for a region server */
336  public static final String SPLIT_LOGDIR_NAME = "splitWAL";
337
338  /** Like the previous, but for old logs that are about to be deleted */
339  public static final String HREGION_OLDLOGDIR_NAME = "oldWALs";
340
341  /** Staging dir used by bulk load */
342  public static final String BULKLOAD_STAGING_DIR_NAME = "staging";
343
344  public static final String CORRUPT_DIR_NAME = "corrupt";
345
346  /** Used by HBCK to sideline backup data */
347  public static final String HBCK_SIDELINEDIR_NAME = ".hbck";
348
349  /** Any artifacts left from migration can be moved here */
350  public static final String MIGRATION_NAME = ".migration";
351
352  /**
353   * The directory from which co-processor/custom filter jars can be loaded
354   * dynamically by the region servers. This value can be overridden by the
355   * hbase.dynamic.jars.dir config.
356   */
357  @Deprecated // unused. see HBASE-12054. remove this in 3.0
358  public static final String LIB_DIR = "lib";
359
360  /** Used to construct the name of the compaction directory during compaction */
361  public static final String HREGION_COMPACTIONDIR_NAME = "compaction.dir";
362
363  /** Conf key for the max file size after which we split the region */
364  public static final String HREGION_MAX_FILESIZE =
365      "hbase.hregion.max.filesize";
366
367  /** Default maximum file size */
368  public static final long DEFAULT_MAX_FILE_SIZE = 10 * 1024 * 1024 * 1024L;
369
370  /**
371   * Max size of single row for Get's or Scan's without in-row scanning flag set.
372   */
373  public static final String TABLE_MAX_ROWSIZE_KEY = "hbase.table.max.rowsize";
374
375  /**
376   * Default max row size (1 Gb).
377   */
378  public static final long TABLE_MAX_ROWSIZE_DEFAULT = 1024 * 1024 * 1024L;
379
380  /**
381   * The max number of threads used for opening and closing stores or store
382   * files in parallel
383   */
384  public static final String HSTORE_OPEN_AND_CLOSE_THREADS_MAX =
385    "hbase.hstore.open.and.close.threads.max";
386
387  /**
388   * The default number for the max number of threads used for opening and
389   * closing stores or store files in parallel
390   */
391  public static final int DEFAULT_HSTORE_OPEN_AND_CLOSE_THREADS_MAX = 1;
392
393  /**
394   * Block updates if memstore has hbase.hregion.memstore.block.multiplier
395   * times hbase.hregion.memstore.flush.size bytes.  Useful preventing
396   * runaway memstore during spikes in update traffic.
397   */
398  public static final String HREGION_MEMSTORE_BLOCK_MULTIPLIER =
399          "hbase.hregion.memstore.block.multiplier";
400
401  /**
402   * Default value for hbase.hregion.memstore.block.multiplier
403   */
404  public static final int DEFAULT_HREGION_MEMSTORE_BLOCK_MULTIPLIER = 4;
405
406  /** Conf key for the memstore size at which we flush the memstore */
407  public static final String HREGION_MEMSTORE_FLUSH_SIZE =
408      "hbase.hregion.memstore.flush.size";
409
410  public static final String HREGION_EDITS_REPLAY_SKIP_ERRORS =
411      "hbase.hregion.edits.replay.skip.errors";
412
413  public static final boolean DEFAULT_HREGION_EDITS_REPLAY_SKIP_ERRORS =
414      false;
415
416  /** Maximum value length, enforced on KeyValue construction */
417  public static final int MAXIMUM_VALUE_LENGTH = Integer.MAX_VALUE - 1;
418
419  /** name of the file for unique cluster ID */
420  public static final String CLUSTER_ID_FILE_NAME = "hbase.id";
421
422  /** Default value for cluster ID */
423  public static final String CLUSTER_ID_DEFAULT = "default-cluster";
424
425  /** Parameter name for # days to keep MVCC values during a major compaction */
426  public static final String KEEP_SEQID_PERIOD = "hbase.hstore.compaction.keep.seqId.period";
427  /** At least to keep MVCC values in hfiles for 5 days */
428  public static final int MIN_KEEP_SEQID_PERIOD = 5;
429
430  // Always store the location of the root table's HRegion.
431  // This HRegion is never split.
432
433  // region name = table + startkey + regionid. This is the row key.
434  // each row in the root and meta tables describes exactly 1 region
435  // Do we ever need to know all the information that we are storing?
436
437  // Note that the name of the root table starts with "-" and the name of the
438  // meta table starts with "." Why? it's a trick. It turns out that when we
439  // store region names in memory, we use a SortedMap. Since "-" sorts before
440  // "." (and since no other table name can start with either of these
441  // characters, the root region will always be the first entry in such a Map,
442  // followed by all the meta regions (which will be ordered by their starting
443  // row key as well), followed by all user tables. So when the Master is
444  // choosing regions to assign, it will always choose the root region first,
445  // followed by the meta regions, followed by user regions. Since the root
446  // and meta regions always need to be on-line, this ensures that they will
447  // be the first to be reassigned if the server(s) they are being served by
448  // should go down.
449
450  public static final String BASE_NAMESPACE_DIR = "data";
451
452  /** delimiter used between portions of a region name */
453  public static final int META_ROW_DELIMITER = ',';
454
455  /** The catalog family as a string*/
456  public static final String CATALOG_FAMILY_STR = "info";
457
458  /** The catalog family */
459  public static final byte [] CATALOG_FAMILY = Bytes.toBytes(CATALOG_FAMILY_STR);
460
461  /** The RegionInfo qualifier as a string */
462  public static final String REGIONINFO_QUALIFIER_STR = "regioninfo";
463
464  /** The regioninfo column qualifier */
465  public static final byte [] REGIONINFO_QUALIFIER = Bytes.toBytes(REGIONINFO_QUALIFIER_STR);
466
467  /** The server column qualifier */
468  public static final String SERVER_QUALIFIER_STR = "server";
469  /** The server column qualifier */
470  public static final byte [] SERVER_QUALIFIER = Bytes.toBytes(SERVER_QUALIFIER_STR);
471
472  /** The startcode column qualifier */
473  public static final String STARTCODE_QUALIFIER_STR = "serverstartcode";
474  /** The startcode column qualifier */
475  public static final byte [] STARTCODE_QUALIFIER = Bytes.toBytes(STARTCODE_QUALIFIER_STR);
476
477  /** The open seqnum column qualifier */
478  public static final String SEQNUM_QUALIFIER_STR = "seqnumDuringOpen";
479  /** The open seqnum column qualifier */
480  public static final byte [] SEQNUM_QUALIFIER = Bytes.toBytes(SEQNUM_QUALIFIER_STR);
481
482  /** The state column qualifier */
483  public static final String STATE_QUALIFIER_STR = "state";
484
485  public static final byte [] STATE_QUALIFIER = Bytes.toBytes(STATE_QUALIFIER_STR);
486
487  /**
488   * The serverName column qualifier. Its the server where the region is
489   * transitioning on, while column server is the server where the region is
490   * opened on. They are the same when the region is in state OPEN.
491   */
492  public static final String SERVERNAME_QUALIFIER_STR = "sn";
493
494  public static final byte [] SERVERNAME_QUALIFIER = Bytes.toBytes(SERVERNAME_QUALIFIER_STR);
495
496  /** The lower-half split region column qualifier */
497  public static final byte [] SPLITA_QUALIFIER = Bytes.toBytes("splitA");
498
499  /** The upper-half split region column qualifier */
500  public static final byte [] SPLITB_QUALIFIER = Bytes.toBytes("splitB");
501
502  /** The lower-half merge region column qualifier */
503  public static final byte[] MERGEA_QUALIFIER = Bytes.toBytes("mergeA");
504
505  /** The upper-half merge region column qualifier */
506  public static final byte[] MERGEB_QUALIFIER = Bytes.toBytes("mergeB");
507
508  /** The catalog family as a string*/
509  public static final String TABLE_FAMILY_STR = "table";
510
511  /** The catalog family */
512  public static final byte [] TABLE_FAMILY = Bytes.toBytes(TABLE_FAMILY_STR);
513
514  /** The serialized table state qualifier */
515  public static final byte[] TABLE_STATE_QUALIFIER = Bytes.toBytes("state");
516
517
518  /**
519   * The meta table version column qualifier.
520   * We keep current version of the meta table in this column in <code>-ROOT-</code>
521   * table: i.e. in the 'info:v' column.
522   */
523  public static final byte [] META_VERSION_QUALIFIER = Bytes.toBytes("v");
524
525  /**
526   * The current version of the meta table.
527   * - pre-hbase 0.92.  There is no META_VERSION column in the root table
528   * in this case. The meta has HTableDescriptor serialized into the HRegionInfo;
529   * - version 0 is 0.92 and 0.94. Meta data has serialized HRegionInfo's using
530   * Writable serialization, and HRegionInfo's does not contain HTableDescriptors.
531   * - version 1 for 0.96+ keeps HRegionInfo data structures, but changes the
532   * byte[] serialization from Writables to Protobuf.
533   * See HRegionInfo.VERSION
534   */
535  public static final short META_VERSION = 1;
536
537  // Other constants
538
539  /**
540   * An empty instance.
541   */
542  public static final byte [] EMPTY_BYTE_ARRAY = new byte [0];
543
544  public static final ByteBuffer EMPTY_BYTE_BUFFER = ByteBuffer.wrap(EMPTY_BYTE_ARRAY);
545
546  /**
547   * Used by scanners, etc when they want to start at the beginning of a region
548   */
549  public static final byte [] EMPTY_START_ROW = EMPTY_BYTE_ARRAY;
550
551  /**
552   * Last row in a table.
553   */
554  public static final byte [] EMPTY_END_ROW = EMPTY_START_ROW;
555
556  /**
557    * Used by scanners and others when they're trying to detect the end of a
558    * table
559    */
560  public static final byte [] LAST_ROW = EMPTY_BYTE_ARRAY;
561
562  /**
563   * Max length a row can have because of the limitation in TFile.
564   */
565  public static final int MAX_ROW_LENGTH = Short.MAX_VALUE;
566
567  /**
568   * Timestamp to use when we want to refer to the latest cell.
569   * This is the timestamp sent by clients when no timestamp is specified on
570   * commit.
571   */
572  public static final long LATEST_TIMESTAMP = Long.MAX_VALUE;
573
574  /**
575   * Timestamp to use when we want to refer to the oldest cell.
576   * Special! Used in fake Cells only. Should never be the timestamp on an actual Cell returned to
577   * a client.
578   * @deprecated Should not be public since hbase-1.3.0. For internal use only. Move internal to
579   *   Scanners flagged as special timestamp value never to be returned as timestamp on a Cell.
580   */
581  @Deprecated
582  public static final long OLDEST_TIMESTAMP = Long.MIN_VALUE;
583
584  /**
585   * LATEST_TIMESTAMP in bytes form
586   */
587  public static final byte [] LATEST_TIMESTAMP_BYTES = {
588    // big-endian
589    (byte) (LATEST_TIMESTAMP >>> 56),
590    (byte) (LATEST_TIMESTAMP >>> 48),
591    (byte) (LATEST_TIMESTAMP >>> 40),
592    (byte) (LATEST_TIMESTAMP >>> 32),
593    (byte) (LATEST_TIMESTAMP >>> 24),
594    (byte) (LATEST_TIMESTAMP >>> 16),
595    (byte) (LATEST_TIMESTAMP >>> 8),
596    (byte) LATEST_TIMESTAMP,
597  };
598
599  /**
600   * Define for 'return-all-versions'.
601   */
602  public static final int ALL_VERSIONS = Integer.MAX_VALUE;
603
604  /**
605   * Unlimited time-to-live.
606   */
607//  public static final int FOREVER = -1;
608  public static final int FOREVER = Integer.MAX_VALUE;
609
610  /**
611   * Seconds in a week
612   */
613  @Deprecated // unused. see HBASE-2692. remove this in 3.0
614  public static final int WEEK_IN_SECONDS = 7 * 24 * 3600;
615
616  /**
617   * Seconds in a day, hour and minute
618   */
619  public static final int DAY_IN_SECONDS = 24 * 60 * 60;
620  public static final int HOUR_IN_SECONDS = 60 * 60;
621  public static final int MINUTE_IN_SECONDS = 60;
622
623  //TODO: although the following are referenced widely to format strings for
624  //      the shell. They really aren't a part of the public API. It would be
625  //      nice if we could put them somewhere where they did not need to be
626  //      public. They could have package visibility
627  public static final String NAME = "NAME";
628  public static final String VERSIONS = "VERSIONS";
629  public static final String IN_MEMORY = "IN_MEMORY";
630  public static final String METADATA = "METADATA";
631  public static final String CONFIGURATION = "CONFIGURATION";
632
633  /**
634   * Retrying we multiply hbase.client.pause setting by what we have in this array until we
635   * run out of array items.  Retries beyond this use the last number in the array.  So, for
636   * example, if hbase.client.pause is 1 second, and maximum retries count
637   * hbase.client.retries.number is 10, we will retry at the following intervals:
638   * 1, 2, 3, 5, 10, 20, 40, 100, 100, 100.
639   * With 100ms, a back-off of 200 means 20s
640   */
641  public static final int [] RETRY_BACKOFF = {1, 2, 3, 5, 10, 20, 40, 100, 100, 100, 100, 200, 200};
642
643  public static final String REGION_IMPL = "hbase.hregion.impl";
644
645  /**
646   * Scope tag for locally scoped data.
647   * This data will not be replicated.
648   */
649  public static final int REPLICATION_SCOPE_LOCAL = 0;
650
651  /**
652   * Scope tag for globally scoped data.
653   * This data will be replicated to all peers.
654   */
655  public static final int REPLICATION_SCOPE_GLOBAL = 1;
656
657  /**
658   * Default cluster ID, cannot be used to identify a cluster so a key with
659   * this value means it wasn't meant for replication.
660   */
661  public static final UUID DEFAULT_CLUSTER_ID = new UUID(0L,0L);
662
663  /**
664   * Parameter name for maximum number of bytes returned when calling a scanner's next method.
665   * Controlled by the client.
666   */
667  public static final String HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE_KEY =
668      "hbase.client.scanner.max.result.size";
669
670  /**
671   * Parameter name for maximum number of bytes returned when calling a scanner's next method.
672   * Controlled by the server.
673   */
674  public static final String HBASE_SERVER_SCANNER_MAX_RESULT_SIZE_KEY =
675      "hbase.server.scanner.max.result.size";
676
677  /**
678   * Maximum number of bytes returned when calling a scanner's next method.
679   * Note that when a single row is larger than this limit the row is still
680   * returned completely.
681   *
682   * The default value is 2MB.
683   */
684  public static final long DEFAULT_HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE = 2 * 1024 * 1024;
685
686  /**
687   * Maximum number of bytes returned when calling a scanner's next method.
688   * Note that when a single row is larger than this limit the row is still
689   * returned completely.
690   * Safety setting to protect the region server.
691   *
692   * The default value is 100MB. (a client would rarely request larger chunks on purpose)
693   */
694  public static final long DEFAULT_HBASE_SERVER_SCANNER_MAX_RESULT_SIZE = 100 * 1024 * 1024;
695
696  /**
697   * Parameter name for client pause value, used mostly as value to wait
698   * before running a retry of a failed get, region lookup, etc.
699   */
700  public static final String HBASE_CLIENT_PAUSE = "hbase.client.pause";
701
702  /**
703   * Default value of {@link #HBASE_CLIENT_PAUSE}.
704   */
705  public static final long DEFAULT_HBASE_CLIENT_PAUSE = 100;
706
707  /**
708   * Parameter name for client pause value for special case such as call queue too big, etc.
709   */
710  public static final String HBASE_CLIENT_PAUSE_FOR_CQTBE = "hbase.client.pause.cqtbe";
711
712  /**
713   * The maximum number of concurrent connections the client will maintain.
714   */
715  public static final String HBASE_CLIENT_MAX_TOTAL_TASKS = "hbase.client.max.total.tasks";
716
717  /**
718   * Default value of {@link #HBASE_CLIENT_MAX_TOTAL_TASKS}.
719   */
720  public static final int DEFAULT_HBASE_CLIENT_MAX_TOTAL_TASKS = 100;
721
722  /**
723   * The maximum number of concurrent connections the client will maintain to a single
724   * RegionServer.
725   */
726  public static final String HBASE_CLIENT_MAX_PERSERVER_TASKS = "hbase.client.max.perserver.tasks";
727
728  /**
729   * Default value of {@link #HBASE_CLIENT_MAX_PERSERVER_TASKS}.
730   */
731  public static final int DEFAULT_HBASE_CLIENT_MAX_PERSERVER_TASKS = 2;
732
733  /**
734   * The maximum number of concurrent connections the client will maintain to a single
735   * Region.
736   */
737  public static final String HBASE_CLIENT_MAX_PERREGION_TASKS = "hbase.client.max.perregion.tasks";
738
739  /**
740   * Default value of {@link #HBASE_CLIENT_MAX_PERREGION_TASKS}.
741   */
742  public static final int DEFAULT_HBASE_CLIENT_MAX_PERREGION_TASKS = 1;
743
744  /**
745   * The maximum number of concurrent pending RPC requests for one server in process level.
746   */
747  public static final String HBASE_CLIENT_PERSERVER_REQUESTS_THRESHOLD =
748      "hbase.client.perserver.requests.threshold";
749
750  /**
751   * Default value of {@link #HBASE_CLIENT_PERSERVER_REQUESTS_THRESHOLD}.
752   */
753  public static final int DEFAULT_HBASE_CLIENT_PERSERVER_REQUESTS_THRESHOLD = Integer.MAX_VALUE;
754
755
756  /**
757   * Parameter name for server pause value, used mostly as value to wait before
758   * running a retry of a failed operation.
759   */
760  public static final String HBASE_SERVER_PAUSE = "hbase.server.pause";
761
762  /**
763   * Default value of {@link #HBASE_SERVER_PAUSE}.
764   */
765  public static final int DEFAULT_HBASE_SERVER_PAUSE = 1000;
766
767  /**
768   * Parameter name for maximum retries, used as maximum for all retryable
769   * operations such as fetching of the root region from root region server,
770   * getting a cell's value, starting a row update, etc.
771   */
772  public static final String HBASE_CLIENT_RETRIES_NUMBER = "hbase.client.retries.number";
773
774  /**
775   * Default value of {@link #HBASE_CLIENT_RETRIES_NUMBER}.
776   */
777  public static final int DEFAULT_HBASE_CLIENT_RETRIES_NUMBER = 15;
778
779  public static final String HBASE_CLIENT_SERVERSIDE_RETRIES_MULTIPLIER =
780      "hbase.client.serverside.retries.multiplier";
781
782  public static final int DEFAULT_HBASE_CLIENT_SERVERSIDE_RETRIES_MULTIPLIER = 3;
783
784  /**
785   * Parameter name to set the default scanner caching for all clients.
786   */
787  public static final String HBASE_CLIENT_SCANNER_CACHING = "hbase.client.scanner.caching";
788
789  /**
790   * Default value for {@link #HBASE_CLIENT_SCANNER_CACHING}
791   */
792  public static final int DEFAULT_HBASE_CLIENT_SCANNER_CACHING = Integer.MAX_VALUE;
793
794  /**
795   * Parameter name for number of rows that will be fetched when calling next on
796   * a scanner if it is not served from memory. Higher caching values will
797   * enable faster scanners but will eat up more memory and some calls of next
798   * may take longer and longer times when the cache is empty.
799   */
800  public static final String HBASE_META_SCANNER_CACHING = "hbase.meta.scanner.caching";
801
802  /**
803   * Default value of {@link #HBASE_META_SCANNER_CACHING}.
804   */
805  public static final int DEFAULT_HBASE_META_SCANNER_CACHING = 100;
806
807  /**
808   * Parameter name for number of versions, kept by meta table.
809   */
810  public static final String HBASE_META_VERSIONS = "hbase.meta.versions";
811
812  /**
813   * Default value of {@link #HBASE_META_VERSIONS}.
814   */
815  public static final int DEFAULT_HBASE_META_VERSIONS = 3;
816
817  /**
818   * Parameter name for number of versions, kept by meta table.
819   */
820  public static final String HBASE_META_BLOCK_SIZE = "hbase.meta.blocksize";
821
822  /**
823   * Default value of {@link #HBASE_META_BLOCK_SIZE}.
824   */
825  public static final int DEFAULT_HBASE_META_BLOCK_SIZE = 8 * 1024;
826
827  /**
828   * Parameter name for unique identifier for this {@link org.apache.hadoop.conf.Configuration}
829   * instance. If there are two or more {@link org.apache.hadoop.conf.Configuration} instances that,
830   * for all intents and purposes, are the same except for their instance ids, then they will not be
831   * able to share the same org.apache.hadoop.hbase.client.HConnection instance. On the other hand,
832   * even if the instance ids are the same, it could result in non-shared
833   * org.apache.hadoop.hbase.client.HConnection instances if some of the other connection parameters
834   * differ.
835   */
836  public static final String HBASE_CLIENT_INSTANCE_ID = "hbase.client.instance.id";
837
838  /**
839   * The client scanner timeout period in milliseconds.
840   */
841  public static final String HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD =
842      "hbase.client.scanner.timeout.period";
843
844  /**
845   * Use {@link #HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD} instead.
846   * @deprecated This config option is deprecated. Will be removed at later releases after 0.96.
847   */
848  @Deprecated
849  public static final String HBASE_REGIONSERVER_LEASE_PERIOD_KEY =
850      "hbase.regionserver.lease.period";
851
852  /**
853   * Default value of {@link #HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD}.
854   */
855  public static final int DEFAULT_HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD = 60000;
856
857  /**
858   * timeout for each RPC
859   */
860  public static final String HBASE_RPC_TIMEOUT_KEY = "hbase.rpc.timeout";
861
862  /**
863   * timeout for each read RPC
864   */
865  public static final String HBASE_RPC_READ_TIMEOUT_KEY = "hbase.rpc.read.timeout";
866
867  /**
868   * timeout for each write RPC
869   */
870  public static final String HBASE_RPC_WRITE_TIMEOUT_KEY = "hbase.rpc.write.timeout";
871
872  /**
873   * Default value of {@link #HBASE_RPC_TIMEOUT_KEY}
874   */
875  public static final int DEFAULT_HBASE_RPC_TIMEOUT = 60000;
876
877  /**
878   * timeout for short operation RPC
879   */
880  public static final String HBASE_RPC_SHORTOPERATION_TIMEOUT_KEY =
881      "hbase.rpc.shortoperation.timeout";
882
883  /**
884   * Default value of {@link #HBASE_RPC_SHORTOPERATION_TIMEOUT_KEY}
885   */
886  public static final int DEFAULT_HBASE_RPC_SHORTOPERATION_TIMEOUT = 10000;
887
888  /**
889   * Value indicating the server name was saved with no sequence number.
890   */
891  public static final long NO_SEQNUM = -1;
892
893
894  /*
895   * cluster replication constants.
896   */
897  public static final String
898      REPLICATION_SOURCE_SERVICE_CLASSNAME = "hbase.replication.source.service";
899  public static final String
900      REPLICATION_SINK_SERVICE_CLASSNAME = "hbase.replication.sink.service";
901  public static final String REPLICATION_SERVICE_CLASSNAME_DEFAULT =
902    "org.apache.hadoop.hbase.replication.regionserver.Replication";
903  public static final String REPLICATION_BULKLOAD_ENABLE_KEY = "hbase.replication.bulkload.enabled";
904  public static final boolean REPLICATION_BULKLOAD_ENABLE_DEFAULT = false;
905  /** Replication cluster id of source cluster which uniquely identifies itself with peer cluster */
906  public static final String REPLICATION_CLUSTER_ID = "hbase.replication.cluster.id";
907  /**
908   * Max total size of buffered entries in all replication peers. It will prevent server getting
909   * OOM if there are many peers. Default value is 256MB which is four times to default
910   * replication.source.size.capacity.
911   */
912  public static final String REPLICATION_SOURCE_TOTAL_BUFFER_KEY = "replication.total.buffer.quota";
913
914  public static final int REPLICATION_SOURCE_TOTAL_BUFFER_DFAULT = 256 * 1024 * 1024;
915
916
917  /**
918   * Directory where the source cluster file system client configuration are placed which is used by
919   * sink cluster to copy HFiles from source cluster file system
920   */
921  public static final String REPLICATION_CONF_DIR = "hbase.replication.conf.dir";
922
923  /** Maximum time to retry for a failed bulk load request */
924  public static final String BULKLOAD_MAX_RETRIES_NUMBER = "hbase.bulkload.retries.number";
925
926  /** HBCK special code name used as server name when manipulating ZK nodes */
927  @Deprecated // unused. see HBASE-3789. remove this in 3.0
928  public static final String HBCK_CODE_NAME = "HBCKServerName";
929
930  public static final String KEY_FOR_HOSTNAME_SEEN_BY_MASTER =
931    "hbase.regionserver.hostname.seen.by.master";
932
933  public static final String HBASE_MASTER_LOGCLEANER_PLUGINS =
934      "hbase.master.logcleaner.plugins";
935
936  public static final String HBASE_REGION_SPLIT_POLICY_KEY =
937    "hbase.regionserver.region.split.policy";
938
939  /** Whether nonces are enabled; default is true. */
940  public static final String HBASE_RS_NONCES_ENABLED = "hbase.regionserver.nonces.enabled";
941
942  /**
943   * Configuration key for the size of the block cache
944   */
945  public static final String HFILE_BLOCK_CACHE_SIZE_KEY =
946    "hfile.block.cache.size";
947
948  public static final float HFILE_BLOCK_CACHE_SIZE_DEFAULT = 0.4f;
949
950  /*
951    * Minimum percentage of free heap necessary for a successful cluster startup.
952    */
953  public static final float HBASE_CLUSTER_MINIMUM_MEMORY_THRESHOLD = 0.2f;
954
955  /**
956   * @deprecated  It is used internally. As of release 2.0.0, this will be removed in HBase 3.0.0.
957   */
958  @Deprecated
959  public static final Pattern CP_HTD_ATTR_KEY_PATTERN =
960      Pattern.compile("^coprocessor\\$([0-9]+)$", Pattern.CASE_INSENSITIVE);
961
962  /**
963   * <pre>
964   * Pattern that matches a coprocessor specification. Form is:
965   * {@code <coprocessor jar file location> '|' <class name> ['|' <priority> ['|' <arguments>]]}
966   * where arguments are {@code <KEY> '=' <VALUE> [,...]}
967   * For example: {@code hdfs:///foo.jar|com.foo.FooRegionObserver|1001|arg1=1,arg2=2}
968   * </pre>
969   * @deprecated  It is used internally. As of release 2.0.0, this will be removed in HBase 3.0.0.
970   */
971  @Deprecated
972  public static final Pattern CP_HTD_ATTR_VALUE_PATTERN =
973      Pattern.compile("(^[^\\|]*)\\|([^\\|]+)\\|[\\s]*([\\d]*)[\\s]*(\\|.*)?$");
974  /**
975   * @deprecated  It is used internally. As of release 2.0.0, this will be removed in HBase 3.0.0.
976   */
977  @Deprecated
978  public static final String CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN = "[^=,]+";
979  /**
980   * @deprecated  It is used internally. As of release 2.0.0, this will be removed in HBase 3.0.0.
981   */
982  @Deprecated
983  public static final String CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN = "[^,]+";
984  /**
985   * @deprecated  It is used internally. As of release 2.0.0, this will be removed in HBase 3.0.0.
986   */
987  @Deprecated
988  public static final Pattern CP_HTD_ATTR_VALUE_PARAM_PATTERN = Pattern.compile(
989      "(" + CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN + ")=(" +
990      CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN + "),?");
991  public static final String CP_HTD_ATTR_INCLUSION_KEY =
992      "hbase.coprocessor.classloader.included.classes";
993
994  /** The delay when re-trying a socket operation in a loop (HBASE-4712) */
995  public static final int SOCKET_RETRY_WAIT_MS = 200;
996
997  /** Host name of the local machine */
998  public static final String LOCALHOST = "localhost";
999
1000  /**
1001   * If this parameter is set to true, then hbase will read
1002   * data and then verify checksums. Checksum verification
1003   * inside hdfs will be switched off.  However, if the hbase-checksum
1004   * verification fails, then it will switch back to using
1005   * hdfs checksums for verifiying data that is being read from storage.
1006   *
1007   * If this parameter is set to false, then hbase will not
1008   * verify any checksums, instead it will depend on checksum verification
1009   * being done in the hdfs client.
1010   */
1011  public static final String HBASE_CHECKSUM_VERIFICATION =
1012      "hbase.regionserver.checksum.verify";
1013
1014  public static final String LOCALHOST_IP = "127.0.0.1";
1015
1016  public static final String REGION_SERVER_HANDLER_COUNT = "hbase.regionserver.handler.count";
1017  public static final int DEFAULT_REGION_SERVER_HANDLER_COUNT = 30;
1018
1019  /*
1020   * REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT:
1021   * -1  => Disable aborting
1022   * 0   => Abort if even a single handler has died
1023   * 0.x => Abort only when this percent of handlers have died
1024   * 1   => Abort only all of the handers have died
1025   */
1026  public static final String REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT =
1027      "hbase.regionserver.handler.abort.on.error.percent";
1028  public static final double DEFAULT_REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT = 0.5;
1029
1030  //High priority handlers to deal with admin requests and system table operation requests
1031  public static final String REGION_SERVER_HIGH_PRIORITY_HANDLER_COUNT =
1032      "hbase.regionserver.metahandler.count";
1033  public static final int DEFAULT_REGION_SERVER_HIGH_PRIORITY_HANDLER_COUNT = 20;
1034
1035  public static final String REGION_SERVER_REPLICATION_HANDLER_COUNT =
1036      "hbase.regionserver.replication.handler.count";
1037  public static final int DEFAULT_REGION_SERVER_REPLICATION_HANDLER_COUNT = 3;
1038
1039  @Deprecated // unused. see HBASE-10569. remove this in 3.0
1040  public static final String MASTER_HANDLER_COUNT = "hbase.master.handler.count";
1041  @Deprecated // unused. see HBASE-10569. remove this in 3.0
1042  public static final int DEFAULT_MASTER_HANLDER_COUNT = 25;
1043
1044  /** Conf key that specifies timeout value to wait for a region ready */
1045  @Deprecated // unused. see HBASE-13616. remove this in 3.0
1046  public static final String LOG_REPLAY_WAIT_REGION_TIMEOUT =
1047      "hbase.master.log.replay.wait.region.timeout";
1048
1049  /** Conf key for enabling meta replication */
1050  public static final String USE_META_REPLICAS = "hbase.meta.replicas.use";
1051  public static final boolean DEFAULT_USE_META_REPLICAS = false;
1052  public static final String META_REPLICAS_NUM = "hbase.meta.replica.count";
1053  public static final int DEFAULT_META_REPLICA_NUM = 1;
1054
1055  /**
1056   * The name of the configuration parameter that specifies
1057   * the number of bytes in a newly created checksum chunk.
1058   */
1059  public static final String BYTES_PER_CHECKSUM =
1060      "hbase.hstore.bytes.per.checksum";
1061
1062  /**
1063   * The name of the configuration parameter that specifies
1064   * the name of an algorithm that is used to compute checksums
1065   * for newly created blocks.
1066   */
1067  public static final String CHECKSUM_TYPE_NAME =
1068      "hbase.hstore.checksum.algorithm";
1069
1070  /** Enable file permission modification from standard hbase */
1071  public static final String ENABLE_DATA_FILE_UMASK = "hbase.data.umask.enable";
1072  /** File permission umask to use when creating hbase data files */
1073  public static final String DATA_FILE_UMASK_KEY = "hbase.data.umask";
1074
1075  /** Configuration name of WAL Compression */
1076  public static final String ENABLE_WAL_COMPRESSION =
1077    "hbase.regionserver.wal.enablecompression";
1078
1079  /** Configuration name of WAL storage policy
1080   * Valid values are: HOT, COLD, WARM, ALL_SSD, ONE_SSD, LAZY_PERSIST
1081   * See http://hadoop.apache.org/docs/r2.7.3/hadoop-project-dist/hadoop-hdfs/ArchivalStorage.html*/
1082  public static final String WAL_STORAGE_POLICY = "hbase.wal.storage.policy";
1083  /**
1084   * "NONE" is not a valid storage policy and means we defer the policy to HDFS. @see
1085   * <a href="https://issues.apache.org/jira/browse/HBASE-20691">HBASE-20691</a>
1086   */
1087  public static final String DEFER_TO_HDFS_STORAGE_POLICY = "NONE";
1088  /** By default we defer the WAL storage policy to HDFS */
1089  public static final String DEFAULT_WAL_STORAGE_POLICY = DEFER_TO_HDFS_STORAGE_POLICY;
1090
1091  /** Region in Transition metrics threshold time */
1092  public static final String METRICS_RIT_STUCK_WARNING_THRESHOLD =
1093      "hbase.metrics.rit.stuck.warning.threshold";
1094
1095  public static final String LOAD_BALANCER_SLOP_KEY = "hbase.regions.slop";
1096
1097  /** delimiter used between portions of a region name */
1098  public static final int DELIMITER = ',';
1099
1100  /**
1101   * QOS attributes: these attributes are used to demarcate RPC call processing
1102   * by different set of handlers. For example, HIGH_QOS tagged methods are
1103   * handled by high priority handlers.
1104   */
1105  // normal_QOS < replication_QOS < replay_QOS < QOS_threshold < admin_QOS < high_QOS
1106  public static final int PRIORITY_UNSET = -1;
1107  public static final int NORMAL_QOS = 0;
1108  public static final int REPLICATION_QOS = 5;
1109  public static final int REPLAY_QOS = 6;
1110  public static final int QOS_THRESHOLD = 10;
1111  public static final int ADMIN_QOS = 100;
1112  public static final int HIGH_QOS = 200;
1113  public static final int SYSTEMTABLE_QOS = HIGH_QOS;
1114
1115  /** Directory under /hbase where archived hfiles are stored */
1116  public static final String HFILE_ARCHIVE_DIRECTORY = "archive";
1117
1118  /**
1119   * Name of the directory to store all snapshots. See SnapshotDescriptionUtils for
1120   * remaining snapshot constants; this is here to keep HConstants dependencies at a minimum and
1121   * uni-directional.
1122   */
1123  public static final String SNAPSHOT_DIR_NAME = ".hbase-snapshot";
1124
1125  /* Name of old snapshot directory. See HBASE-8352 for details on why it needs to be renamed */
1126  public static final String OLD_SNAPSHOT_DIR_NAME = ".snapshot";
1127
1128  /** Temporary directory used for table creation and deletion */
1129  public static final String HBASE_TEMP_DIRECTORY = ".tmp";
1130  /**
1131   * The period (in milliseconds) between computing region server point in time metrics
1132   */
1133  public static final String REGIONSERVER_METRICS_PERIOD = "hbase.regionserver.metrics.period";
1134  public static final long DEFAULT_REGIONSERVER_METRICS_PERIOD = 5000;
1135  /** Directories that are not HBase table directories */
1136  public static final List<String> HBASE_NON_TABLE_DIRS =
1137    Collections.unmodifiableList(Arrays.asList(new String[] {
1138      HBCK_SIDELINEDIR_NAME, HBASE_TEMP_DIRECTORY, MIGRATION_NAME
1139    }));
1140
1141  /** Directories that are not HBase user table directories */
1142  public static final List<String> HBASE_NON_USER_TABLE_DIRS =
1143    Collections.unmodifiableList(Arrays.asList((String[])ArrayUtils.addAll(
1144      new String[] { TableName.META_TABLE_NAME.getNameAsString() },
1145      HBASE_NON_TABLE_DIRS.toArray())));
1146
1147  /** Health script related settings. */
1148  public static final String HEALTH_SCRIPT_LOC = "hbase.node.health.script.location";
1149  public static final String HEALTH_SCRIPT_TIMEOUT = "hbase.node.health.script.timeout";
1150  public static final String HEALTH_CHORE_WAKE_FREQ =
1151      "hbase.node.health.script.frequency";
1152  public static final long DEFAULT_HEALTH_SCRIPT_TIMEOUT = 60000;
1153  /**
1154   * The maximum number of health check failures a server can encounter consecutively.
1155   */
1156  public static final String HEALTH_FAILURE_THRESHOLD =
1157      "hbase.node.health.failure.threshold";
1158  public static final int DEFAULT_HEALTH_FAILURE_THRESHOLD = 3;
1159
1160
1161  /**
1162   * Setting to activate, or not, the publication of the status by the master. Default
1163   *  notification is by a multicast message.
1164   */
1165  public static final String STATUS_PUBLISHED = "hbase.status.published";
1166  public static final boolean STATUS_PUBLISHED_DEFAULT = false;
1167
1168  /**
1169   * IP to use for the multicast status messages between the master and the clients.
1170   * The default address is chosen as one among others within the ones suitable for multicast
1171   * messages.
1172   */
1173  public static final String STATUS_MULTICAST_ADDRESS = "hbase.status.multicast.address.ip";
1174  public static final String DEFAULT_STATUS_MULTICAST_ADDRESS = "226.1.1.3";
1175
1176  /**
1177   * The address to use for binding the local socket for receiving multicast. Defaults to
1178   * 0.0.0.0.
1179   * @see <a href="https://issues.apache.org/jira/browse/HBASE-9961">HBASE-9961</a>
1180   */
1181  public static final String STATUS_MULTICAST_BIND_ADDRESS =
1182      "hbase.status.multicast.bind.address.ip";
1183  public static final String DEFAULT_STATUS_MULTICAST_BIND_ADDRESS = "0.0.0.0";
1184
1185  /**
1186   * The port to use for the multicast messages.
1187   */
1188  public static final String STATUS_MULTICAST_PORT = "hbase.status.multicast.address.port";
1189  public static final int DEFAULT_STATUS_MULTICAST_PORT = 16100;
1190
1191  /**
1192   * The network interface name to use for the multicast messages.
1193   */
1194  public static final String STATUS_MULTICAST_NI_NAME = "hbase.status.multicast.ni.name";
1195
1196  /**
1197   * The address to use for binding the local socket for sending multicast. Defaults to 0.0.0.0.
1198   */
1199  public static final String STATUS_MULTICAST_PUBLISHER_BIND_ADDRESS =
1200    "hbase.status.multicast.publisher.bind.address.ip";
1201  public static final String DEFAULT_STATUS_MULTICAST_PUBLISHER_BIND_ADDRESS = "0.0.0.0";
1202
1203  public static final long NO_NONCE = 0;
1204
1205  /** Default cipher for encryption */
1206  public static final String CIPHER_AES = "AES";
1207
1208  /** Configuration key for the crypto algorithm provider, a class name */
1209  public static final String CRYPTO_CIPHERPROVIDER_CONF_KEY = "hbase.crypto.cipherprovider";
1210
1211  /** Configuration key for the crypto key provider, a class name */
1212  public static final String CRYPTO_KEYPROVIDER_CONF_KEY = "hbase.crypto.keyprovider";
1213
1214  /** Configuration key for the crypto key provider parameters */
1215  public static final String CRYPTO_KEYPROVIDER_PARAMETERS_KEY =
1216      "hbase.crypto.keyprovider.parameters";
1217
1218  /** Configuration key for the name of the master key for the cluster, a string */
1219  public static final String CRYPTO_MASTERKEY_NAME_CONF_KEY = "hbase.crypto.master.key.name";
1220
1221  /** Configuration key for the name of the alternate master key for the cluster, a string */
1222  public static final String CRYPTO_MASTERKEY_ALTERNATE_NAME_CONF_KEY =
1223    "hbase.crypto.master.alternate.key.name";
1224
1225  /** Configuration key for the algorithm to use when encrypting the WAL, a string */
1226  public static final String CRYPTO_WAL_ALGORITHM_CONF_KEY = "hbase.crypto.wal.algorithm";
1227
1228  /** Configuration key for the name of the master WAL encryption key for the cluster, a string */
1229  public static final String CRYPTO_WAL_KEY_NAME_CONF_KEY = "hbase.crypto.wal.key.name";
1230
1231  /** Configuration key for the algorithm used for creating jks key, a string */
1232  public static final String CRYPTO_KEY_ALGORITHM_CONF_KEY = "hbase.crypto.key.algorithm";
1233
1234  /** Configuration key for the name of the alternate cipher algorithm for the cluster, a string */
1235  public static final String CRYPTO_ALTERNATE_KEY_ALGORITHM_CONF_KEY =
1236      "hbase.crypto.alternate.key.algorithm";
1237
1238  /** Configuration key for enabling WAL encryption, a boolean */
1239  public static final String ENABLE_WAL_ENCRYPTION = "hbase.regionserver.wal.encryption";
1240
1241  /** Configuration key for setting RPC codec class name */
1242  public static final String RPC_CODEC_CONF_KEY = "hbase.client.rpc.codec";
1243
1244  /** Configuration key for setting replication codec class name */
1245  public static final String REPLICATION_CODEC_CONF_KEY = "hbase.replication.rpc.codec";
1246
1247  /** Maximum number of threads used by the replication source for shipping edits to the sinks */
1248  public static final String REPLICATION_SOURCE_MAXTHREADS_KEY =
1249      "hbase.replication.source.maxthreads";
1250
1251  /** Drop edits for tables that been deleted from the replication source and target */
1252  public static final String REPLICATION_DROP_ON_DELETED_TABLE_KEY =
1253      "hbase.replication.drop.on.deleted.table";
1254
1255  /** Maximum number of threads used by the replication source for shipping edits to the sinks */
1256  public static final int REPLICATION_SOURCE_MAXTHREADS_DEFAULT = 10;
1257
1258  /** Configuration key for SplitLog manager timeout */
1259  public static final String HBASE_SPLITLOG_MANAGER_TIMEOUT = "hbase.splitlog.manager.timeout";
1260
1261  /**
1262   * Configuration keys for Bucket cache
1263   */
1264  // TODO moving these bucket cache implementation specific configs to this level is violation of
1265  // encapsulation. But as these has to be referred from hbase-common and bucket cache
1266  // sits in hbase-server, there were no other go! Can we move the cache implementation to
1267  // hbase-common?
1268
1269  /**
1270   * Current ioengine options in include: heap, offheap and file:PATH (where PATH is the path
1271   * to the file that will host the file-based cache.  See BucketCache#getIOEngineFromName() for
1272   * list of supported ioengine options.
1273   * <p>Set this option and a non-zero {@link #BUCKET_CACHE_SIZE_KEY} to enable bucket cache.
1274   */
1275  public static final String BUCKET_CACHE_IOENGINE_KEY = "hbase.bucketcache.ioengine";
1276
1277  /**
1278   * When using bucket cache, this is a float that EITHER represents a percentage of total heap
1279   * memory size to give to the cache (if &lt; 1.0) OR, it is the capacity in
1280   * megabytes of the cache.
1281   */
1282  public static final String BUCKET_CACHE_SIZE_KEY = "hbase.bucketcache.size";
1283
1284  /**
1285   * HConstants for fast fail on the client side follow
1286   */
1287  /**
1288   * Config for enabling/disabling the fast fail mode.
1289   */
1290  public static final String HBASE_CLIENT_FAST_FAIL_MODE_ENABLED =
1291      "hbase.client.fast.fail.mode.enabled";
1292
1293  public static final boolean HBASE_CLIENT_ENABLE_FAST_FAIL_MODE_DEFAULT =
1294      false;
1295
1296  public static final String HBASE_CLIENT_FAST_FAIL_THREASHOLD_MS =
1297      "hbase.client.fastfail.threshold";
1298
1299  public static final long HBASE_CLIENT_FAST_FAIL_THREASHOLD_MS_DEFAULT =
1300      60000;
1301
1302  public static final String HBASE_CLIENT_FAST_FAIL_CLEANUP_MS_DURATION_MS =
1303      "hbase.client.fast.fail.cleanup.duration";
1304
1305  public static final long HBASE_CLIENT_FAST_FAIL_CLEANUP_DURATION_MS_DEFAULT =
1306      600000;
1307
1308  public static final String HBASE_CLIENT_FAST_FAIL_INTERCEPTOR_IMPL =
1309      "hbase.client.fast.fail.interceptor.impl";
1310
1311  /** Config key for if the server should send backpressure and if the client should listen to
1312   * that backpressure from the server */
1313  public static final String ENABLE_CLIENT_BACKPRESSURE = "hbase.client.backpressure.enabled";
1314  public static final boolean DEFAULT_ENABLE_CLIENT_BACKPRESSURE = false;
1315
1316  public static final String HEAP_OCCUPANCY_LOW_WATERMARK_KEY =
1317      "hbase.heap.occupancy.low_water_mark";
1318  public static final float DEFAULT_HEAP_OCCUPANCY_LOW_WATERMARK = 0.95f;
1319  public static final String HEAP_OCCUPANCY_HIGH_WATERMARK_KEY =
1320      "hbase.heap.occupancy.high_water_mark";
1321  public static final float DEFAULT_HEAP_OCCUPANCY_HIGH_WATERMARK = 0.98f;
1322
1323  /**
1324   * The max number of threads used for splitting storefiles in parallel during
1325   * the region split process.
1326   */
1327  public static final String REGION_SPLIT_THREADS_MAX =
1328    "hbase.regionserver.region.split.threads.max";
1329
1330  /** Canary config keys */
1331  public static final String HBASE_CANARY_WRITE_DATA_TTL_KEY = "hbase.canary.write.data.ttl";
1332
1333  public static final String HBASE_CANARY_WRITE_PERSERVER_REGIONS_LOWERLIMIT_KEY =
1334      "hbase.canary.write.perserver.regions.lowerLimit";
1335
1336  public static final String HBASE_CANARY_WRITE_PERSERVER_REGIONS_UPPERLIMIT_KEY =
1337      "hbase.canary.write.perserver.regions.upperLimit";
1338
1339  public static final String HBASE_CANARY_WRITE_VALUE_SIZE_KEY = "hbase.canary.write.value.size";
1340
1341  public static final String HBASE_CANARY_WRITE_TABLE_CHECK_PERIOD_KEY =
1342      "hbase.canary.write.table.check.period";
1343
1344  public static final String HBASE_CANARY_READ_RAW_SCAN_KEY = "hbase.canary.read.raw.enabled";
1345
1346  /**
1347   * Configuration keys for programmatic JAAS configuration for secured ZK interaction
1348   */
1349  public static final String ZK_CLIENT_KEYTAB_FILE = "hbase.zookeeper.client.keytab.file";
1350  public static final String ZK_CLIENT_KERBEROS_PRINCIPAL =
1351      "hbase.zookeeper.client.kerberos.principal";
1352  public static final String ZK_SERVER_KEYTAB_FILE = "hbase.zookeeper.server.keytab.file";
1353  public static final String ZK_SERVER_KERBEROS_PRINCIPAL =
1354      "hbase.zookeeper.server.kerberos.principal";
1355
1356  /** Config key for hbase temporary directory in hdfs */
1357  public static final String TEMPORARY_FS_DIRECTORY_KEY = "hbase.fs.tmp.dir";
1358  public static final String DEFAULT_TEMPORARY_HDFS_DIRECTORY = "/user/"
1359      + System.getProperty("user.name") + "/hbase-staging";
1360
1361  public static final String SNAPSHOT_RESTORE_TAKE_FAILSAFE_SNAPSHOT =
1362      "hbase.snapshot.restore.take.failsafe.snapshot";
1363  public static final boolean DEFAULT_SNAPSHOT_RESTORE_TAKE_FAILSAFE_SNAPSHOT = true;
1364
1365  public static final String SNAPSHOT_RESTORE_FAILSAFE_NAME =
1366      "hbase.snapshot.restore.failsafe.name";
1367  public static final String DEFAULT_SNAPSHOT_RESTORE_FAILSAFE_NAME =
1368      "hbase-failsafe-{snapshot.name}-{restore.timestamp}";
1369
1370  public static final String DEFAULT_LOSSY_COUNTING_ERROR_RATE =
1371      "hbase.util.default.lossycounting.errorrate";
1372  public static final String NOT_IMPLEMENTED = "Not implemented";
1373
1374  private HConstants() {
1375    // Can't be instantiated with this ctor.
1376  }
1377}