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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.classification.InterfaceAudience;
32  import org.apache.hadoop.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 ByteBuffer RPC_HEADER = ByteBuffer.wrap("HBas".getBytes());
66    public static final byte RPC_CURRENT_VERSION = 0;
67  
68    // HFileBlock constants.
69  
70    /** The size data structures with minor version is 0 */
71    public static final int HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM = MAGIC_LENGTH + 2 * Bytes.SIZEOF_INT
72        + Bytes.SIZEOF_LONG;
73    /** The size of a version 2 HFile block header, minor version 1.
74     * There is a 1 byte checksum type, followed by a 4 byte bytesPerChecksum
75     * followed by another 4 byte value to store sizeofDataOnDisk.
76     */
77    public static final int HFILEBLOCK_HEADER_SIZE = HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM +
78      Bytes.SIZEOF_BYTE + 2 * Bytes.SIZEOF_INT;
79    /** Just an array of bytes of the right size. */
80    public static final byte[] HFILEBLOCK_DUMMY_HEADER = new byte[HFILEBLOCK_HEADER_SIZE];
81  
82    //End HFileBlockConstants.
83  
84    /**
85     * Status codes used for return values of bulk operations.
86     */
87    public enum OperationStatusCode {
88      NOT_RUN,
89      SUCCESS,
90      BAD_FAMILY,
91      SANITY_CHECK_FAILURE,
92      FAILURE;
93    }
94  
95    /** long constant for zero */
96    public static final Long ZERO_L = Long.valueOf(0L);
97    public static final String NINES = "99999999999999";
98    public static final String ZEROES = "00000000000000";
99  
100   // For migration
101 
102   /** name of version file */
103   public static final String VERSION_FILE_NAME = "hbase.version";
104 
105   /**
106    * Current version of file system.
107    * Version 4 supports only one kind of bloom filter.
108    * Version 5 changes versions in catalog table regions.
109    * Version 6 enables blockcaching on catalog tables.
110    * Version 7 introduces hfile -- hbase 0.19 to 0.20..
111    * Version 8 introduces namespace
112    */
113   // public static final String FILE_SYSTEM_VERSION = "6";
114   public static final String FILE_SYSTEM_VERSION = "8";
115 
116   // Configuration parameters
117 
118   //TODO: Is having HBase homed on port 60k OK?
119 
120   /** Cluster is in distributed mode or not */
121   public static final String CLUSTER_DISTRIBUTED = "hbase.cluster.distributed";
122 
123   /** Config for pluggable load balancers */
124   public static final String HBASE_MASTER_LOADBALANCER_CLASS = "hbase.master.loadbalancer.class";
125 
126   /** Cluster is standalone or pseudo-distributed */
127   public static final boolean CLUSTER_IS_LOCAL = false;
128 
129   /** Cluster is fully-distributed */
130   public static final boolean CLUSTER_IS_DISTRIBUTED = true;
131 
132   /** Default value for cluster distributed mode */
133   public static final boolean DEFAULT_CLUSTER_DISTRIBUTED = CLUSTER_IS_LOCAL;
134 
135   /** default host address */
136   public static final String DEFAULT_HOST = "0.0.0.0";
137 
138   /** Parameter name for port master listens on. */
139   public static final String MASTER_PORT = "hbase.master.port";
140 
141   /** default port that the master listens on */
142   public static final int DEFAULT_MASTER_PORT = 16000;
143 
144   /** default port for master web api */
145   public static final int DEFAULT_MASTER_INFOPORT = 16010;
146 
147   /** Configuration key for master web API port */
148   public static final String MASTER_INFO_PORT = "hbase.master.info.port";
149 
150   /** Parameter name for the master type being backup (waits for primary to go inactive). */
151   public static final String MASTER_TYPE_BACKUP = "hbase.master.backup";
152 
153   /** by default every master is a possible primary master unless the conf explicitly overrides it */
154   public static final boolean DEFAULT_MASTER_TYPE_BACKUP = false;
155 
156   /** Name of ZooKeeper quorum configuration parameter. */
157   public static final String ZOOKEEPER_QUORUM = "hbase.zookeeper.quorum";
158 
159   /** Name of ZooKeeper config file in conf/ directory. */
160   public static final String ZOOKEEPER_CONFIG_NAME = "zoo.cfg";
161 
162   /** Common prefix of ZooKeeper configuration properties */
163   public static final String ZK_CFG_PROPERTY_PREFIX =
164       "hbase.zookeeper.property.";
165 
166   public static final int ZK_CFG_PROPERTY_PREFIX_LEN =
167       ZK_CFG_PROPERTY_PREFIX.length();
168 
169   /**
170    * The ZK client port key in the ZK properties map. The name reflects the
171    * fact that this is not an HBase configuration key.
172    */
173   public static final String CLIENT_PORT_STR = "clientPort";
174 
175   /** Parameter name for the client port that the zookeeper listens on */
176   public static final String ZOOKEEPER_CLIENT_PORT =
177       ZK_CFG_PROPERTY_PREFIX + CLIENT_PORT_STR;
178 
179   /** Default client port that the zookeeper listens on */
180   public static final int DEFAULT_ZOOKEPER_CLIENT_PORT = 2181;
181 
182   /** Parameter name for the wait time for the recoverable zookeeper */
183   public static final String ZOOKEEPER_RECOVERABLE_WAITTIME = "hbase.zookeeper.recoverable.waittime";
184 
185   /** Default wait time for the recoverable zookeeper */
186   public static final long DEFAULT_ZOOKEPER_RECOVERABLE_WAITIME = 10000;
187 
188   /** Parameter name for the root dir in ZK for this cluster */
189   public static final String ZOOKEEPER_ZNODE_PARENT = "zookeeper.znode.parent";
190 
191   public static final String DEFAULT_ZOOKEEPER_ZNODE_PARENT = "/hbase";
192 
193   /**
194    * Parameter name for the limit on concurrent client-side zookeeper
195    * connections
196    */
197   public static final String ZOOKEEPER_MAX_CLIENT_CNXNS =
198       ZK_CFG_PROPERTY_PREFIX + "maxClientCnxns";
199 
200   /** Parameter name for the ZK data directory */
201   public static final String ZOOKEEPER_DATA_DIR =
202       ZK_CFG_PROPERTY_PREFIX + "dataDir";
203 
204   /** Default limit on concurrent client-side zookeeper connections */
205   public static final int DEFAULT_ZOOKEPER_MAX_CLIENT_CNXNS = 300;
206 
207   /** Configuration key for ZooKeeper session timeout */
208   public static final String ZK_SESSION_TIMEOUT = "zookeeper.session.timeout";
209 
210   /** Default value for ZooKeeper session timeout */
211   public static final int DEFAULT_ZK_SESSION_TIMEOUT = 180 * 1000;
212 
213   /** Configuration key for whether to use ZK.multi */
214   public static final String ZOOKEEPER_USEMULTI = "hbase.zookeeper.useMulti";
215 
216   /** Parameter name for port region server listens on. */
217   public static final String REGIONSERVER_PORT = "hbase.regionserver.port";
218 
219   /** Default port region server listens on. */
220   public static final int DEFAULT_REGIONSERVER_PORT = 16020;
221 
222   /** default port for region server web api */
223   public static final int DEFAULT_REGIONSERVER_INFOPORT = 16030;
224 
225   /** A configuration key for regionserver info port */
226   public static final String REGIONSERVER_INFO_PORT =
227     "hbase.regionserver.info.port";
228 
229   /** A flag that enables automatic selection of regionserver info port */
230   public static final String REGIONSERVER_INFO_PORT_AUTO =
231       REGIONSERVER_INFO_PORT + ".auto";
232 
233   /** Parameter name for what region server implementation to use. */
234   public static final String REGION_SERVER_IMPL= "hbase.regionserver.impl";
235 
236   /** Parameter name for what master implementation to use. */
237   public static final String MASTER_IMPL= "hbase.master.impl";
238 
239   /** Parameter name for what hbase client implementation to use. */
240   public static final String HBASECLIENT_IMPL= "hbase.hbaseclient.impl";
241 
242   /** Parameter name for how often threads should wake up */
243   public static final String THREAD_WAKE_FREQUENCY = "hbase.server.thread.wakefrequency";
244 
245   /** Default value for thread wake frequency */
246   public static final int DEFAULT_THREAD_WAKE_FREQUENCY = 10 * 1000;
247 
248   /** Parameter name for how often we should try to write a version file, before failing */
249   public static final String VERSION_FILE_WRITE_ATTEMPTS = "hbase.server.versionfile.writeattempts";
250 
251   /** Parameter name for how often we should try to write a version file, before failing */
252   public static final int DEFAULT_VERSION_FILE_WRITE_ATTEMPTS = 3;
253 
254   /** Parameter name for how often a region should should perform a major compaction */
255   public static final String MAJOR_COMPACTION_PERIOD = "hbase.hregion.majorcompaction";
256 
257   /** Parameter name for the maximum batch of KVs to be used in flushes and compactions */
258   public static final String COMPACTION_KV_MAX = "hbase.hstore.compaction.kv.max";
259   public static final int COMPACTION_KV_MAX_DEFAULT = 10;
260 
261   /** Parameter name for HBase instance root directory */
262   public static final String HBASE_DIR = "hbase.rootdir";
263 
264   /** Parameter name for HBase client IPC pool type */
265   public static final String HBASE_CLIENT_IPC_POOL_TYPE = "hbase.client.ipc.pool.type";
266 
267   /** Parameter name for HBase client IPC pool size */
268   public static final String HBASE_CLIENT_IPC_POOL_SIZE = "hbase.client.ipc.pool.size";
269 
270   /** Parameter name for HBase client operation timeout, which overrides RPC timeout */
271   public static final String HBASE_CLIENT_OPERATION_TIMEOUT = "hbase.client.operation.timeout";
272 
273   /** Parameter name for HBase client operation timeout, which overrides RPC timeout */
274   public static final String HBASE_CLIENT_META_OPERATION_TIMEOUT =
275     "hbase.client.meta.operation.timeout";
276 
277   /** Default HBase client operation timeout, which is tantamount to a blocking call */
278   public static final int DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT = Integer.MAX_VALUE;
279 
280   /** Used to construct the name of the log directory for a region server */
281   public static final String HREGION_LOGDIR_NAME = "WALs";
282 
283   /** Used to construct the name of the splitlog directory for a region server */
284   public static final String SPLIT_LOGDIR_NAME = "splitWAL";
285 
286   /** Like the previous, but for old logs that are about to be deleted */
287   public static final String HREGION_OLDLOGDIR_NAME = "oldWALs";
288 
289   public static final String CORRUPT_DIR_NAME = "corrupt";
290 
291   /** Used by HBCK to sideline backup data */
292   public static final String HBCK_SIDELINEDIR_NAME = ".hbck";
293 
294   /** Any artifacts left from migration can be moved here */
295   public static final String MIGRATION_NAME = ".migration";
296 
297   /**
298    * The directory from which co-processor/custom filter jars can be loaded
299    * dynamically by the region servers. This value can be overridden by the
300    * hbase.dynamic.jars.dir config.
301    */
302   public static final String LIB_DIR = "lib";
303 
304   /** Used to construct the name of the compaction directory during compaction */
305   public static final String HREGION_COMPACTIONDIR_NAME = "compaction.dir";
306 
307   /** Conf key for the max file size after which we split the region */
308   public static final String HREGION_MAX_FILESIZE =
309       "hbase.hregion.max.filesize";
310 
311   /** Default maximum file size */
312   public static final long DEFAULT_MAX_FILE_SIZE = 10 * 1024 * 1024 * 1024L;
313 
314   /**
315    * Max size of single row for Get's or Scan's without in-row scanning flag set.
316    */
317   public static final String TABLE_MAX_ROWSIZE_KEY = "hbase.table.max.rowsize";
318 
319   /**
320    * Default max row size (1 Gb).
321    */
322   public static final long TABLE_MAX_ROWSIZE_DEFAULT = 1024 * 1024 * 1024L;
323 
324   /**
325    * The max number of threads used for opening and closing stores or store
326    * files in parallel
327    */
328   public static final String HSTORE_OPEN_AND_CLOSE_THREADS_MAX =
329     "hbase.hstore.open.and.close.threads.max";
330 
331   /**
332    * The default number for the max number of threads used for opening and
333    * closing stores or store files in parallel
334    */
335   public static final int DEFAULT_HSTORE_OPEN_AND_CLOSE_THREADS_MAX = 1;
336 
337 
338   /** Conf key for the memstore size at which we flush the memstore */
339   public static final String HREGION_MEMSTORE_FLUSH_SIZE =
340       "hbase.hregion.memstore.flush.size";
341 
342   public static final String HREGION_EDITS_REPLAY_SKIP_ERRORS =
343       "hbase.hregion.edits.replay.skip.errors";
344 
345   public static final boolean DEFAULT_HREGION_EDITS_REPLAY_SKIP_ERRORS =
346       false;
347 
348   /** Maximum value length, enforced on KeyValue construction */
349   public static final int MAXIMUM_VALUE_LENGTH = Integer.MAX_VALUE - 1;
350 
351   /** name of the file for unique cluster ID */
352   public static final String CLUSTER_ID_FILE_NAME = "hbase.id";
353 
354   /** Default value for cluster ID */
355   public static final String CLUSTER_ID_DEFAULT = "default-cluster";
356 
357   /** Parameter name for # days to keep MVCC values during a major compaction */
358   public static final String KEEP_SEQID_PERIOD = "hbase.hstore.compaction.keep.seqId.period";
359   /** At least to keep MVCC values in hfiles for 5 days */
360   public static final int MIN_KEEP_SEQID_PERIOD = 5;
361 
362   // Always store the location of the root table's HRegion.
363   // This HRegion is never split.
364 
365   // region name = table + startkey + regionid. This is the row key.
366   // each row in the root and meta tables describes exactly 1 region
367   // Do we ever need to know all the information that we are storing?
368 
369   // Note that the name of the root table starts with "-" and the name of the
370   // meta table starts with "." Why? it's a trick. It turns out that when we
371   // store region names in memory, we use a SortedMap. Since "-" sorts before
372   // "." (and since no other table name can start with either of these
373   // characters, the root region will always be the first entry in such a Map,
374   // followed by all the meta regions (which will be ordered by their starting
375   // row key as well), followed by all user tables. So when the Master is
376   // choosing regions to assign, it will always choose the root region first,
377   // followed by the meta regions, followed by user regions. Since the root
378   // and meta regions always need to be on-line, this ensures that they will
379   // be the first to be reassigned if the server(s) they are being served by
380   // should go down.
381 
382 
383   /** The hbase:meta table's name. */
384   @Deprecated  // for compat from 0.94 -> 0.96.
385   public static final byte[] META_TABLE_NAME = TableName.META_TABLE_NAME.getName();
386 
387   public static final String BASE_NAMESPACE_DIR = "data";
388 
389   /** delimiter used between portions of a region name */
390   public static final int META_ROW_DELIMITER = ',';
391 
392   /** The catalog family as a string*/
393   public static final String CATALOG_FAMILY_STR = "info";
394 
395   /** The catalog family */
396   public static final byte [] CATALOG_FAMILY = Bytes.toBytes(CATALOG_FAMILY_STR);
397 
398   /** The RegionInfo qualifier as a string */
399   public static final String REGIONINFO_QUALIFIER_STR = "regioninfo";
400 
401   /** The regioninfo column qualifier */
402   public static final byte [] REGIONINFO_QUALIFIER = Bytes.toBytes(REGIONINFO_QUALIFIER_STR);
403 
404   /** The server column qualifier */
405   public static final String SERVER_QUALIFIER_STR = "server";
406   /** The server column qualifier */
407   public static final byte [] SERVER_QUALIFIER = Bytes.toBytes(SERVER_QUALIFIER_STR);
408 
409   /** The startcode column qualifier */
410   public static final String STARTCODE_QUALIFIER_STR = "serverstartcode";
411   /** The startcode column qualifier */
412   public static final byte [] STARTCODE_QUALIFIER = Bytes.toBytes(STARTCODE_QUALIFIER_STR);
413 
414   /** The open seqnum column qualifier */
415   public static final String SEQNUM_QUALIFIER_STR = "seqnumDuringOpen";
416   /** The open seqnum column qualifier */
417   public static final byte [] SEQNUM_QUALIFIER = Bytes.toBytes(SEQNUM_QUALIFIER_STR);
418 
419   /** The state column qualifier */
420   public static final String STATE_QUALIFIER_STR = "state";
421 
422   public static final byte [] STATE_QUALIFIER = Bytes.toBytes(STATE_QUALIFIER_STR);
423 
424   /**
425    * The serverName column qualifier. Its the server where the region is
426    * transitioning on, while column server is the server where the region is
427    * opened on. They are the same when the region is in state OPEN.
428    */
429   public static final String SERVERNAME_QUALIFIER_STR = "sn";
430 
431   public static final byte [] SERVERNAME_QUALIFIER = Bytes.toBytes(SERVERNAME_QUALIFIER_STR);
432 
433   /** The lower-half split region column qualifier */
434   public static final byte [] SPLITA_QUALIFIER = Bytes.toBytes("splitA");
435 
436   /** The upper-half split region column qualifier */
437   public static final byte [] SPLITB_QUALIFIER = Bytes.toBytes("splitB");
438 
439   /** The lower-half merge region column qualifier */
440   public static final byte[] MERGEA_QUALIFIER = Bytes.toBytes("mergeA");
441 
442   /** The upper-half merge region column qualifier */
443   public static final byte[] MERGEB_QUALIFIER = Bytes.toBytes("mergeB");
444 
445   /**
446    * The meta table version column qualifier.
447    * We keep current version of the meta table in this column in <code>-ROOT-</code>
448    * table: i.e. in the 'info:v' column.
449    */
450   public static final byte [] META_VERSION_QUALIFIER = Bytes.toBytes("v");
451 
452   /**
453    * The current version of the meta table.
454    * - pre-hbase 0.92.  There is no META_VERSION column in the root table
455    * in this case. The meta has HTableDescriptor serialized into the HRegionInfo;
456    * - version 0 is 0.92 and 0.94. Meta data has serialized HRegionInfo's using
457    * Writable serialization, and HRegionInfo's does not contain HTableDescriptors.
458    * - version 1 for 0.96+ keeps HRegionInfo data structures, but changes the
459    * byte[] serialization from Writables to Protobuf.
460    * See HRegionInfo.VERSION
461    */
462   public static final short META_VERSION = 1;
463 
464   // Other constants
465 
466   /**
467    * An empty instance.
468    */
469   public static final byte [] EMPTY_BYTE_ARRAY = new byte [0];
470 
471   /**
472    * Used by scanners, etc when they want to start at the beginning of a region
473    */
474   public static final byte [] EMPTY_START_ROW = EMPTY_BYTE_ARRAY;
475 
476   /**
477    * Last row in a table.
478    */
479   public static final byte [] EMPTY_END_ROW = EMPTY_START_ROW;
480 
481   /**
482     * Used by scanners and others when they're trying to detect the end of a
483     * table
484     */
485   public static final byte [] LAST_ROW = EMPTY_BYTE_ARRAY;
486 
487   /**
488    * Max length a row can have because of the limitation in TFile.
489    */
490   public static final int MAX_ROW_LENGTH = Short.MAX_VALUE;
491 
492   /**
493    * Timestamp to use when we want to refer to the latest cell.
494    * This is the timestamp sent by clients when no timestamp is specified on
495    * commit.
496    */
497   public static final long LATEST_TIMESTAMP = Long.MAX_VALUE;
498 
499   /**
500    * Timestamp to use when we want to refer to the oldest cell.
501    */
502   public static final long OLDEST_TIMESTAMP = Long.MIN_VALUE;
503 
504   /**
505    * LATEST_TIMESTAMP in bytes form
506    */
507   public static final byte [] LATEST_TIMESTAMP_BYTES = {
508     // big-endian
509     (byte) (LATEST_TIMESTAMP >>> 56),
510     (byte) (LATEST_TIMESTAMP >>> 48),
511     (byte) (LATEST_TIMESTAMP >>> 40),
512     (byte) (LATEST_TIMESTAMP >>> 32),
513     (byte) (LATEST_TIMESTAMP >>> 24),
514     (byte) (LATEST_TIMESTAMP >>> 16),
515     (byte) (LATEST_TIMESTAMP >>> 8),
516     (byte) LATEST_TIMESTAMP,
517   };
518 
519   /**
520    * Define for 'return-all-versions'.
521    */
522   public static final int ALL_VERSIONS = Integer.MAX_VALUE;
523 
524   /**
525    * Unlimited time-to-live.
526    */
527 //  public static final int FOREVER = -1;
528   public static final int FOREVER = Integer.MAX_VALUE;
529 
530   /**
531    * Seconds in a week
532    */
533   public static final int WEEK_IN_SECONDS = 7 * 24 * 3600;
534 
535   /**
536    * Seconds in a day, hour and minute
537    */
538   public static final int DAY_IN_SECONDS = 24 * 60 * 60;
539   public static final int HOUR_IN_SECONDS = 60 * 60;
540   public static final int MINUTE_IN_SECONDS = 60;
541 
542   //TODO: although the following are referenced widely to format strings for
543   //      the shell. They really aren't a part of the public API. It would be
544   //      nice if we could put them somewhere where they did not need to be
545   //      public. They could have package visibility
546   public static final String NAME = "NAME";
547   public static final String VERSIONS = "VERSIONS";
548   public static final String IN_MEMORY = "IN_MEMORY";
549   public static final String METADATA = "METADATA";
550   public static final String CONFIGURATION = "CONFIGURATION";
551 
552   /**
553    * Retrying we multiply hbase.client.pause setting by what we have in this array until we
554    * run out of array items.  Retries beyond this use the last number in the array.  So, for
555    * example, if hbase.client.pause is 1 second, and maximum retries count
556    * hbase.client.retries.number is 10, we will retry at the following intervals:
557    * 1, 2, 3, 5, 10, 20, 40, 100, 100, 100.
558    * With 100ms, a back-off of 200 means 20s
559    */
560   public static int RETRY_BACKOFF[] = { 1, 2, 3, 5, 10, 20, 40, 100, 100, 100, 100, 200, 200 };
561 
562   public static final String REGION_IMPL = "hbase.hregion.impl";
563 
564   /** modifyTable op for replacing the table descriptor */
565   public static enum Modify {
566     CLOSE_REGION,
567     TABLE_COMPACT,
568     TABLE_FLUSH,
569     TABLE_MAJOR_COMPACT,
570     TABLE_SET_HTD,
571     TABLE_SPLIT
572   }
573 
574   /**
575    * Scope tag for locally scoped data.
576    * This data will not be replicated.
577    */
578   public static final int REPLICATION_SCOPE_LOCAL = 0;
579 
580   /**
581    * Scope tag for globally scoped data.
582    * This data will be replicated to all peers.
583    */
584   public static final int REPLICATION_SCOPE_GLOBAL = 1;
585 
586   /**
587    * Default cluster ID, cannot be used to identify a cluster so a key with
588    * this value means it wasn't meant for replication.
589    */
590   public static final UUID DEFAULT_CLUSTER_ID = new UUID(0L,0L);
591 
592     /**
593      * Parameter name for maximum number of bytes returned when calling a
594      * scanner's next method.
595      */
596   public static String HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE_KEY = "hbase.client.scanner.max.result.size";
597 
598   /**
599    * Maximum number of bytes returned when calling a scanner's next method.
600    * Note that when a single row is larger than this limit the row is still
601    * returned completely.
602    *
603    * The default value is unlimited.
604    */
605   public static long DEFAULT_HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE = Long.MAX_VALUE;
606 
607   /**
608    * Parameter name for client pause value, used mostly as value to wait
609    * before running a retry of a failed get, region lookup, etc.
610    */
611   public static String HBASE_CLIENT_PAUSE = "hbase.client.pause";
612 
613   /**
614    * Default value of {@link #HBASE_CLIENT_PAUSE}.
615    */
616   public static long DEFAULT_HBASE_CLIENT_PAUSE = 100;
617 
618   /**
619    * The maximum number of concurrent connections the client will maintain.
620    */
621   public static final String HBASE_CLIENT_MAX_TOTAL_TASKS = "hbase.client.max.total.tasks";
622 
623   /**
624    * Default value of {@link #HBASE_CLIENT_MAX_TOTAL_TASKS}.
625    */
626   public static final int DEFAULT_HBASE_CLIENT_MAX_TOTAL_TASKS = 100;
627 
628   /**
629    * The maximum number of concurrent connections the client will maintain to a single
630    * RegionServer.
631    */
632   public static final String HBASE_CLIENT_MAX_PERSERVER_TASKS = "hbase.client.max.perserver.tasks";
633 
634   /**
635    * Default value of {@link #HBASE_CLIENT_MAX_PERSERVER_TASKS}.
636    */
637   public static final int DEFAULT_HBASE_CLIENT_MAX_PERSERVER_TASKS = 2;
638 
639   /**
640    * The maximum number of concurrent connections the client will maintain to a single
641    * Region.
642    */
643   public static final String HBASE_CLIENT_MAX_PERREGION_TASKS = "hbase.client.max.perregion.tasks";
644 
645   /**
646    * Default value of {@link #HBASE_CLIENT_MAX_PERREGION_TASKS}.
647    */
648   public static final int DEFAULT_HBASE_CLIENT_MAX_PERREGION_TASKS = 1;
649 
650   /**
651    * Parameter name for server pause value, used mostly as value to wait before
652    * running a retry of a failed operation.
653    */
654   public static String HBASE_SERVER_PAUSE = "hbase.server.pause";
655 
656   /**
657    * Default value of {@link #HBASE_SERVER_PAUSE}.
658    */
659   public static int DEFAULT_HBASE_SERVER_PAUSE = 1000;
660 
661   /**
662    * Parameter name for maximum retries, used as maximum for all retryable
663    * operations such as fetching of the root region from root region server,
664    * getting a cell's value, starting a row update, etc.
665    */
666   public static String HBASE_CLIENT_RETRIES_NUMBER = "hbase.client.retries.number";
667 
668   /**
669    * Default value of {@link #HBASE_CLIENT_RETRIES_NUMBER}.
670    */
671   public static int DEFAULT_HBASE_CLIENT_RETRIES_NUMBER = 31;
672 
673   /**
674    * Parameter name to set the default scanner caching for all clients.
675    */
676   public static String HBASE_CLIENT_SCANNER_CACHING = "hbase.client.scanner.caching";
677 
678   /**
679    * Default value for {@link #HBASE_CLIENT_SCANNER_CACHING}
680    */
681   public static int DEFAULT_HBASE_CLIENT_SCANNER_CACHING = 100;
682 
683   /**
684    * Parameter name for number of rows that will be fetched when calling next on
685    * a scanner if it is not served from memory. Higher caching values will
686    * enable faster scanners but will eat up more memory and some calls of next
687    * may take longer and longer times when the cache is empty.
688    */
689   public static String HBASE_META_SCANNER_CACHING = "hbase.meta.scanner.caching";
690 
691   /**
692    * Default value of {@link #HBASE_META_SCANNER_CACHING}.
693    */
694   public static int DEFAULT_HBASE_META_SCANNER_CACHING = 100;
695 
696   /**
697    * Parameter name for unique identifier for this {@link org.apache.hadoop.conf.Configuration}
698    * instance. If there are two or more {@link org.apache.hadoop.conf.Configuration} instances that,
699    * for all intents and purposes, are the same except for their instance ids, then they will not be
700    * able to share the same org.apache.hadoop.hbase.client.HConnection instance. On the other hand,
701    * even if the instance ids are the same, it could result in non-shared
702    * org.apache.hadoop.hbase.client.HConnection instances if some of the other connection parameters
703    * differ.
704    */
705   public static String HBASE_CLIENT_INSTANCE_ID = "hbase.client.instance.id";
706 
707   /**
708    * The client scanner timeout period in milliseconds.
709    */
710   public static String HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD = "hbase.client.scanner.timeout.period";
711 
712   /**
713    * Use {@link #HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD} instead.
714    * @deprecated This config option is deprecated. Will be removed at later releases after 0.96.
715    */
716   @Deprecated
717   public static String HBASE_REGIONSERVER_LEASE_PERIOD_KEY =
718       "hbase.regionserver.lease.period";
719 
720   /**
721    * Default value of {@link #HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD}.
722    */
723   public static int DEFAULT_HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD = 60000;
724 
725   /**
726    * timeout for each RPC
727    */
728   public static String HBASE_RPC_TIMEOUT_KEY = "hbase.rpc.timeout";
729 
730   /**
731    * Default value of {@link #HBASE_RPC_TIMEOUT_KEY}
732    */
733   public static int DEFAULT_HBASE_RPC_TIMEOUT = 60000;
734 
735   /**
736    * timeout for short operation RPC
737    */
738   public static String HBASE_RPC_SHORTOPERATION_TIMEOUT_KEY = "hbase.rpc.shortoperation.timeout";
739 
740   /**
741    * Default value of {@link #HBASE_RPC_SHORTOPERATION_TIMEOUT_KEY}
742    */
743   public static int DEFAULT_HBASE_RPC_SHORTOPERATION_TIMEOUT = 10000;
744 
745   /**
746    * Value indicating the server name was saved with no sequence number.
747    */
748   public static final long NO_SEQNUM = -1;
749 
750 
751   /*
752    * cluster replication constants.
753    */
754   public static final String
755       REPLICATION_ENABLE_KEY = "hbase.replication";
756   public static final boolean
757       REPLICATION_ENABLE_DEFAULT = true;
758   public static final String
759       REPLICATION_SOURCE_SERVICE_CLASSNAME = "hbase.replication.source.service";
760   public static final String
761       REPLICATION_SINK_SERVICE_CLASSNAME = "hbase.replication.sink.service";
762   public static final String REPLICATION_SERVICE_CLASSNAME_DEFAULT =
763     "org.apache.hadoop.hbase.replication.regionserver.Replication";
764 
765   /** HBCK special code name used as server name when manipulating ZK nodes */
766   public static final String HBCK_CODE_NAME = "HBCKServerName";
767 
768   public static final String KEY_FOR_HOSTNAME_SEEN_BY_MASTER =
769     "hbase.regionserver.hostname.seen.by.master";
770 
771   public static final String HBASE_MASTER_LOGCLEANER_PLUGINS =
772       "hbase.master.logcleaner.plugins";
773 
774   public static final String HBASE_REGION_SPLIT_POLICY_KEY =
775     "hbase.regionserver.region.split.policy";
776 
777   /** Whether nonces are enabled; default is true. */
778   public static String HBASE_RS_NONCES_ENABLED = "hbase.regionserver.nonces.enabled";
779 
780   /**
781    * Configuration key for the size of the block cache
782    */
783   public static final String HFILE_BLOCK_CACHE_SIZE_KEY =
784     "hfile.block.cache.size";
785 
786   public static final float HFILE_BLOCK_CACHE_SIZE_DEFAULT = 0.4f;
787 
788   /*
789     * Minimum percentage of free heap necessary for a successful cluster startup.
790     */
791   public static final float HBASE_CLUSTER_MINIMUM_MEMORY_THRESHOLD = 0.2f;
792 
793   public static final Pattern CP_HTD_ATTR_KEY_PATTERN = Pattern.compile
794       ("^coprocessor\\$([0-9]+)$", Pattern.CASE_INSENSITIVE);
795   public static final Pattern CP_HTD_ATTR_VALUE_PATTERN =
796       Pattern.compile("(^[^\\|]*)\\|([^\\|]+)\\|[\\s]*([\\d]*)[\\s]*(\\|.*)?$");
797 
798   public static final String CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN = "[^=,]+";
799   public static final String CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN = "[^,]+";
800   public static final Pattern CP_HTD_ATTR_VALUE_PARAM_PATTERN = Pattern.compile(
801       "(" + CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN + ")=(" +
802       CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN + "),?");
803 
804   /** The delay when re-trying a socket operation in a loop (HBASE-4712) */
805   public static final int SOCKET_RETRY_WAIT_MS = 200;
806 
807   /** Host name of the local machine */
808   public static final String LOCALHOST = "localhost";
809 
810   /**
811    * If this parameter is set to true, then hbase will read
812    * data and then verify checksums. Checksum verification
813    * inside hdfs will be switched off.  However, if the hbase-checksum
814    * verification fails, then it will switch back to using
815    * hdfs checksums for verifiying data that is being read from storage.
816    *
817    * If this parameter is set to false, then hbase will not
818    * verify any checksums, instead it will depend on checksum verification
819    * being done in the hdfs client.
820    */
821   public static final String HBASE_CHECKSUM_VERIFICATION =
822       "hbase.regionserver.checksum.verify";
823 
824   public static final String LOCALHOST_IP = "127.0.0.1";
825 
826   /** Conf key that enables unflushed WAL edits directly being replayed to region servers */
827   public static final String DISTRIBUTED_LOG_REPLAY_KEY = "hbase.master.distributed.log.replay";
828   /**
829    * Default 'distributed log replay' as true since hbase 0.99.0
830    */
831   public static final boolean DEFAULT_DISTRIBUTED_LOG_REPLAY_CONFIG = true;
832   public static final String DISALLOW_WRITES_IN_RECOVERING =
833       "hbase.regionserver.disallow.writes.when.recovering";
834   public static final boolean DEFAULT_DISALLOW_WRITES_IN_RECOVERING_CONFIG = false;
835 
836   public static final String REGION_SERVER_HANDLER_COUNT = "hbase.regionserver.handler.count";
837   public static final int DEFAULT_REGION_SERVER_HANDLER_COUNT = 30;
838 
839   public static final String REGION_SERVER_META_HANDLER_COUNT =
840       "hbase.regionserver.metahandler.count";
841   public static final int DEFAULT_REGION_SERVER_META_HANDLER_COUNT = 10;
842 
843   public static final String REGION_SERVER_REPLICATION_HANDLER_COUNT =
844       "hbase.regionserver.replication.handler.count";
845   public static final int DEFAULT_REGION_SERVER_REPLICATION_HANDLER_COUNT = 3;
846 
847   public static final String MASTER_HANDLER_COUNT = "hbase.master.handler.count";
848   public static final int DEFAULT_MASTER_HANLDER_COUNT = 25;
849 
850   /** Conf key that specifies timeout value to wait for a region ready */
851   public static final String LOG_REPLAY_WAIT_REGION_TIMEOUT =
852       "hbase.master.log.replay.wait.region.timeout";
853 
854   /**
855    * The name of the configuration parameter that specifies
856    * the number of bytes in a newly created checksum chunk.
857    */
858   public static final String BYTES_PER_CHECKSUM =
859       "hbase.hstore.bytes.per.checksum";
860 
861   /**
862    * The name of the configuration parameter that specifies
863    * the name of an algorithm that is used to compute checksums
864    * for newly created blocks.
865    */
866   public static final String CHECKSUM_TYPE_NAME =
867       "hbase.hstore.checksum.algorithm";
868 
869   /** Enable file permission modification from standard hbase */
870   public static final String ENABLE_DATA_FILE_UMASK = "hbase.data.umask.enable";
871   /** File permission umask to use when creating hbase data files */
872   public static final String DATA_FILE_UMASK_KEY = "hbase.data.umask";
873 
874   /** Configuration name of HLog Compression */
875   public static final String ENABLE_WAL_COMPRESSION =
876     "hbase.regionserver.wal.enablecompression";
877 
878   /** Region in Transition metrics threshold time */
879   public static final String METRICS_RIT_STUCK_WARNING_THRESHOLD="hbase.metrics.rit.stuck.warning.threshold";
880 
881   public static final String LOAD_BALANCER_SLOP_KEY = "hbase.regions.slop";
882 
883   /**
884    * The byte array represents for NO_NEXT_INDEXED_KEY;
885    * The actual value is irrelevant because this is always compared by reference.
886    */
887   public static final byte [] NO_NEXT_INDEXED_KEY = Bytes.toBytes("NO_NEXT_INDEXED_KEY");
888   /** delimiter used between portions of a region name */
889   public static final int DELIMITER = ',';
890   public static final String HBASE_CONFIG_READ_ZOOKEEPER_CONFIG =
891       "hbase.config.read.zookeeper.config";
892   public static final boolean DEFAULT_HBASE_CONFIG_READ_ZOOKEEPER_CONFIG =
893       false;
894 
895   /**
896    * QOS attributes: these attributes are used to demarcate RPC call processing
897    * by different set of handlers. For example, HIGH_QOS tagged methods are
898    * handled by high priority handlers.
899    */
900   public static final int NORMAL_QOS = 0;
901   public static final int QOS_THRESHOLD = 10;
902   public static final int HIGH_QOS = 100;
903   public static final int REPLICATION_QOS = 5; // normal_QOS < replication_QOS < high_QOS
904   public static final int REPLAY_QOS = 6; // REPLICATION_QOS < REPLAY_QOS < high_QOS
905 
906   /** Directory under /hbase where archived hfiles are stored */
907   public static final String HFILE_ARCHIVE_DIRECTORY = "archive";
908 
909   /**
910    * Name of the directory to store all snapshots. See SnapshotDescriptionUtils for
911    * remaining snapshot constants; this is here to keep HConstants dependencies at a minimum and
912    * uni-directional.
913    */
914   public static final String SNAPSHOT_DIR_NAME = ".hbase-snapshot";
915 
916   /* Name of old snapshot directory. See HBASE-8352 for details on why it needs to be renamed */
917   public static final String OLD_SNAPSHOT_DIR_NAME = ".snapshot";
918 
919   /** Temporary directory used for table creation and deletion */
920   public static final String HBASE_TEMP_DIRECTORY = ".tmp";
921   /**
922    * The period (in milliseconds) between computing region server point in time metrics
923    */
924   public static final String REGIONSERVER_METRICS_PERIOD = "hbase.regionserver.metrics.period";
925   public static final long DEFAULT_REGIONSERVER_METRICS_PERIOD = 5000;
926   /** Directories that are not HBase table directories */
927   public static final List<String> HBASE_NON_TABLE_DIRS =
928     Collections.unmodifiableList(Arrays.asList(new String[] { HREGION_LOGDIR_NAME,
929       HREGION_OLDLOGDIR_NAME, CORRUPT_DIR_NAME, SPLIT_LOGDIR_NAME,
930       HBCK_SIDELINEDIR_NAME, HFILE_ARCHIVE_DIRECTORY, SNAPSHOT_DIR_NAME, HBASE_TEMP_DIRECTORY,
931       OLD_SNAPSHOT_DIR_NAME, BASE_NAMESPACE_DIR, MIGRATION_NAME, LIB_DIR}));
932 
933   /** Directories that are not HBase user table directories */
934   public static final List<String> HBASE_NON_USER_TABLE_DIRS =
935     Collections.unmodifiableList(Arrays.asList((String[])ArrayUtils.addAll(
936       new String[] { TableName.META_TABLE_NAME.getNameAsString() },
937       HBASE_NON_TABLE_DIRS.toArray())));
938 
939   /** Health script related settings. */
940   public static final String HEALTH_SCRIPT_LOC = "hbase.node.health.script.location";
941   public static final String HEALTH_SCRIPT_TIMEOUT = "hbase.node.health.script.timeout";
942   public static final String HEALTH_CHORE_WAKE_FREQ =
943       "hbase.node.health.script.frequency";
944   public static final long DEFAULT_HEALTH_SCRIPT_TIMEOUT = 60000;
945   /**
946    * The maximum number of health check failures a server can encounter consecutively.
947    */
948   public static final String HEALTH_FAILURE_THRESHOLD =
949       "hbase.node.health.failure.threshold";
950   public static final int DEFAULT_HEALTH_FAILURE_THRESHOLD = 3;
951 
952 
953   /**
954    * Setting to activate, or not, the publication of the status by the master. Default
955    *  notification is by a multicast message.
956    */
957   public static final String STATUS_PUBLISHED = "hbase.status.published";
958   public static final boolean STATUS_PUBLISHED_DEFAULT = false;
959 
960   /**
961    * IP to use for the multicast status messages between the master and the clients.
962    * The default address is chosen as one among others within the ones suitable for multicast
963    * messages.
964    */
965   public static final String STATUS_MULTICAST_ADDRESS = "hbase.status.multicast.address.ip";
966   public static final String DEFAULT_STATUS_MULTICAST_ADDRESS = "226.1.1.3";
967 
968   /**
969    * The address to use for binding the local socket for receiving multicast. Defaults to
970    * 0.0.0.0.
971    * @see <a href="https://issues.apache.org/jira/browse/HBASE-9961">HBASE-9961</a>
972    */
973   public static final String STATUS_MULTICAST_BIND_ADDRESS = "hbase.status.multicast.bind.address.ip";
974   public static final String DEFAULT_STATUS_MULTICAST_BIND_ADDRESS = "0.0.0.0";
975 
976   /**
977    * The port to use for the multicast messages.
978    */
979   public static final String STATUS_MULTICAST_PORT = "hbase.status.multicast.address.port";
980   public static final int DEFAULT_STATUS_MULTICAST_PORT = 16100;
981 
982   public static final long NO_NONCE = 0;
983 
984   /** Configuration key for the crypto algorithm provider, a class name */
985   public static final String CRYPTO_CIPHERPROVIDER_CONF_KEY = "hbase.crypto.cipherprovider";
986 
987   /** Configuration key for the crypto key provider, a class name */
988   public static final String CRYPTO_KEYPROVIDER_CONF_KEY = "hbase.crypto.keyprovider";
989 
990   /** Configuration key for the crypto key provider parameters */
991   public static final String CRYPTO_KEYPROVIDER_PARAMETERS_KEY =
992       "hbase.crypto.keyprovider.parameters";
993 
994   /** Configuration key for the name of the master key for the cluster, a string */
995   public static final String CRYPTO_MASTERKEY_NAME_CONF_KEY = "hbase.crypto.master.key.name";
996 
997   /** Configuration key for the name of the alternate master key for the cluster, a string */
998   public static final String CRYPTO_MASTERKEY_ALTERNATE_NAME_CONF_KEY =
999     "hbase.crypto.master.alternate.key.name";
1000 
1001   /** Configuration key for the algorithm to use when encrypting the WAL, a string */
1002   public static final String CRYPTO_WAL_ALGORITHM_CONF_KEY = "hbase.crypto.wal.algorithm";
1003 
1004   /** Configuration key for the name of the master WAL encryption key for the cluster, a string */
1005   public static final String CRYPTO_WAL_KEY_NAME_CONF_KEY = "hbase.crypto.wal.key.name";
1006 
1007   /** Configuration key for enabling HLog encryption, a boolean */
1008   public static final String ENABLE_WAL_ENCRYPTION = "hbase.regionserver.wal.encryption";
1009 
1010   /** Configuration key for setting RPC codec class name */
1011   public static final String RPC_CODEC_CONF_KEY = "hbase.client.rpc.codec";
1012 
1013   /** Configuration key for setting replication codec class name */
1014   public static final String REPLICATION_CODEC_CONF_KEY = "hbase.replication.rpc.codec";
1015 
1016   /** Config for pluggable consensus provider */
1017   public static final String HBASE_COORDINATED_STATE_MANAGER_CLASS =
1018     "hbase.coordinated.state.manager.class";
1019 
1020   /** Configuration key for SplitLog manager timeout */
1021   public static final String HBASE_SPLITLOG_MANAGER_TIMEOUT = "hbase.splitlog.manager.timeout";
1022 
1023   /**
1024    * Configuration keys for Bucket cache
1025    */
1026   // TODO moving these bucket cache implementation specific configs to this level is violation of
1027   // encapsulation. But as these has to be referred from hbase-common and bucket cache
1028   // sits in hbase-server, there were no other go! Can we move the cache implementation to
1029   // hbase-common?
1030 
1031   /**
1032    * Current ioengine options in include: heap, offheap and file:PATH (where PATH is the path
1033    * to the file that will host the file-based cache.  See BucketCache#getIOEngineFromName() for
1034    * list of supported ioengine options.
1035    * <p>Set this option and a non-zero {@link #BUCKET_CACHE_SIZE_KEY} to enable bucket cache.
1036    */
1037   public static final String BUCKET_CACHE_IOENGINE_KEY = "hbase.bucketcache.ioengine";
1038 
1039   /**
1040    * When using bucket cache, this is a float that EITHER represents a percentage of total heap
1041    * memory size to give to the cache (if < 1.0) OR, it is the capacity in megabytes of the cache.
1042    */
1043   public static final String BUCKET_CACHE_SIZE_KEY = "hbase.bucketcache.size";
1044 
1045   private HConstants() {
1046     // Can't be instantiated with this ctor.
1047   }
1048 }