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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    //Bytes.UTF8_ENCODING should be updated if this changed
42    /** When we encode strings, we always specify UTF8 encoding */
43    public static final String UTF8_ENCODING = "UTF-8";
44  
45    //Bytes.UTF8_CHARSET should be updated if this changed
46    /** When we encode strings, we always specify UTF8 encoding */
47    public static final Charset UTF8_CHARSET = Charset.forName(UTF8_ENCODING);
48    /**
49     * Default block size for an HFile.
50     */
51    public final static int DEFAULT_BLOCKSIZE = 64 * 1024;
52  
53    /** Used as a magic return value while optimized index key feature enabled(HBASE-7845) */
54    public final static int INDEX_KEY_MAGIC = -2;
55    /*
56       * Name of directory that holds recovered edits written by the wal log
57       * splitting code, one per region
58       */
59    public static final String RECOVERED_EDITS_DIR = "recovered.edits";
60    /**
61     * The first four bytes of Hadoop RPC connections
62     */
63    public static final ByteBuffer RPC_HEADER = ByteBuffer.wrap("HBas".getBytes());
64    public static final byte RPC_CURRENT_VERSION = 0;
65  
66    // HFileBlock constants.
67  
68    /** The size data structures with minor version is 0 */
69    public static final int HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM = MAGIC_LENGTH + 2 * Bytes.SIZEOF_INT
70        + Bytes.SIZEOF_LONG;
71    /** The size of a version 2 HFile block header, minor version 1.
72     * There is a 1 byte checksum type, followed by a 4 byte bytesPerChecksum
73     * followed by another 4 byte value to store sizeofDataOnDisk.
74     */
75    public static final int HFILEBLOCK_HEADER_SIZE = HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM +
76      Bytes.SIZEOF_BYTE + 2 * Bytes.SIZEOF_INT;
77    /** Just an array of bytes of the right size. */
78    public static final byte[] HFILEBLOCK_DUMMY_HEADER = new byte[HFILEBLOCK_HEADER_SIZE];
79  
80    //End HFileBlockConstants.
81  
82    /**
83     * Status codes used for return values of bulk operations.
84     */
85    public enum OperationStatusCode {
86      NOT_RUN,
87      SUCCESS,
88      BAD_FAMILY,
89      SANITY_CHECK_FAILURE,
90      FAILURE;
91    }
92  
93    /** long constant for zero */
94    public static final Long ZERO_L = Long.valueOf(0L);
95    public static final String NINES = "99999999999999";
96    public static final String ZEROES = "00000000000000";
97  
98    // For migration
99  
100   /** name of version file */
101   public static final String VERSION_FILE_NAME = "hbase.version";
102 
103   /**
104    * Current version of file system.
105    * Version 4 supports only one kind of bloom filter.
106    * Version 5 changes versions in catalog table regions.
107    * Version 6 enables blockcaching on catalog tables.
108    * Version 7 introduces hfile -- hbase 0.19 to 0.20..
109    * Version 8 introduces namespace
110    */
111   // public static final String FILE_SYSTEM_VERSION = "6";
112   public static final String FILE_SYSTEM_VERSION = "8";
113 
114   // Configuration parameters
115 
116   //TODO: Is having HBase homed on port 60k OK?
117 
118   /** Cluster is in distributed mode or not */
119   public static final String CLUSTER_DISTRIBUTED = "hbase.cluster.distributed";
120 
121   /** Config for pluggable load balancers */
122   public static final String HBASE_MASTER_LOADBALANCER_CLASS = "hbase.master.loadbalancer.class";
123 
124   /** Cluster is standalone or pseudo-distributed */
125   public static final boolean CLUSTER_IS_LOCAL = false;
126 
127   /** Cluster is fully-distributed */
128   public static final boolean CLUSTER_IS_DISTRIBUTED = true;
129 
130   /** Default value for cluster distributed mode */
131   public static final boolean DEFAULT_CLUSTER_DISTRIBUTED = CLUSTER_IS_LOCAL;
132 
133   /** default host address */
134   public static final String DEFAULT_HOST = "0.0.0.0";
135 
136   /** Parameter name for port master listens on. */
137   public static final String MASTER_PORT = "hbase.master.port";
138 
139   /** default port that the master listens on */
140   public static final int DEFAULT_MASTER_PORT = 60000;
141 
142   /** default port for master web api */
143   public static final int DEFAULT_MASTER_INFOPORT = 60010;
144 
145   /** Configuration key for master web API port */
146   public static final String MASTER_INFO_PORT = "hbase.master.info.port";
147 
148   /** Parameter name for the master type being backup (waits for primary to go inactive). */
149   public static final String MASTER_TYPE_BACKUP = "hbase.master.backup";
150 
151   /** by default every master is a possible primary master unless the conf explicitly overrides it */
152   public static final boolean DEFAULT_MASTER_TYPE_BACKUP = false;
153 
154   /** Name of ZooKeeper quorum configuration parameter. */
155   public static final String ZOOKEEPER_QUORUM = "hbase.zookeeper.quorum";
156 
157   /** Name of ZooKeeper config file in conf/ directory. */
158   public static final String ZOOKEEPER_CONFIG_NAME = "zoo.cfg";
159 
160   /** Common prefix of ZooKeeper configuration properties */
161   public static final String ZK_CFG_PROPERTY_PREFIX =
162       "hbase.zookeeper.property.";
163 
164   public static final int ZK_CFG_PROPERTY_PREFIX_LEN =
165       ZK_CFG_PROPERTY_PREFIX.length();
166 
167   /**
168    * The ZK client port key in the ZK properties map. The name reflects the
169    * fact that this is not an HBase configuration key.
170    */
171   public static final String CLIENT_PORT_STR = "clientPort";
172 
173   /** Parameter name for the client port that the zookeeper listens on */
174   public static final String ZOOKEEPER_CLIENT_PORT =
175       ZK_CFG_PROPERTY_PREFIX + CLIENT_PORT_STR;
176 
177   /** Default client port that the zookeeper listens on */
178   public static final int DEFAULT_ZOOKEPER_CLIENT_PORT = 2181;
179 
180   /** Parameter name for the wait time for the recoverable zookeeper */
181   public static final String ZOOKEEPER_RECOVERABLE_WAITTIME = "hbase.zookeeper.recoverable.waittime";
182 
183   /** Default wait time for the recoverable zookeeper */
184   public static final long DEFAULT_ZOOKEPER_RECOVERABLE_WAITIME = 10000;
185 
186   /** Parameter name for the root dir in ZK for this cluster */
187   public static final String ZOOKEEPER_ZNODE_PARENT = "zookeeper.znode.parent";
188 
189   public static final String DEFAULT_ZOOKEEPER_ZNODE_PARENT = "/hbase";
190 
191   /**
192    * Parameter name for the limit on concurrent client-side zookeeper
193    * connections
194    */
195   public static final String ZOOKEEPER_MAX_CLIENT_CNXNS =
196       ZK_CFG_PROPERTY_PREFIX + "maxClientCnxns";
197 
198   /** Parameter name for the ZK data directory */
199   public static final String ZOOKEEPER_DATA_DIR =
200       ZK_CFG_PROPERTY_PREFIX + "dataDir";
201 
202   /** Default limit on concurrent client-side zookeeper connections */
203   public static final int DEFAULT_ZOOKEPER_MAX_CLIENT_CNXNS = 300;
204 
205   /** Configuration key for ZooKeeper session timeout */
206   public static final String ZK_SESSION_TIMEOUT = "zookeeper.session.timeout";
207 
208   /** Default value for ZooKeeper session timeout */
209   public static final int DEFAULT_ZK_SESSION_TIMEOUT = 180 * 1000;
210 
211   /** Configuration key for whether to use ZK.multi */
212   public static final String ZOOKEEPER_USEMULTI = "hbase.zookeeper.useMulti";
213 
214   /** Parameter name for port region server listens on. */
215   public static final String REGIONSERVER_PORT = "hbase.regionserver.port";
216 
217   /** Default port region server listens on. */
218   public static final int DEFAULT_REGIONSERVER_PORT = 60020;
219 
220   /** default port for region server web api */
221   public static final int DEFAULT_REGIONSERVER_INFOPORT = 60030;
222 
223   /** A configuration key for regionserver info port */
224   public static final String REGIONSERVER_INFO_PORT =
225     "hbase.regionserver.info.port";
226 
227   /** A flag that enables automatic selection of regionserver info port */
228   public static final String REGIONSERVER_INFO_PORT_AUTO =
229       REGIONSERVER_INFO_PORT + ".auto";
230 
231   /** Parameter name for what region server implementation to use. */
232   public static final String REGION_SERVER_IMPL= "hbase.regionserver.impl";
233 
234   /** Parameter name for what master implementation to use. */
235   public static final String MASTER_IMPL= "hbase.master.impl";
236 
237   /** Parameter name for what hbase client implementation to use. */
238   public static final String HBASECLIENT_IMPL= "hbase.hbaseclient.impl";
239 
240   /** Parameter name for how often threads should wake up */
241   public static final String THREAD_WAKE_FREQUENCY = "hbase.server.thread.wakefrequency";
242 
243   /** Default value for thread wake frequency */
244   public static final int DEFAULT_THREAD_WAKE_FREQUENCY = 10 * 1000;
245 
246   /** Parameter name for how often we should try to write a version file, before failing */
247   public static final String VERSION_FILE_WRITE_ATTEMPTS = "hbase.server.versionfile.writeattempts";
248 
249   /** Parameter name for how often we should try to write a version file, before failing */
250   public static final int DEFAULT_VERSION_FILE_WRITE_ATTEMPTS = 3;
251 
252   /** Parameter name for how often a region should should perform a major compaction */
253   public static final String MAJOR_COMPACTION_PERIOD = "hbase.hregion.majorcompaction";
254 
255   /** Parameter name for the maximum batch of KVs to be used in flushes and compactions */
256   public static final String COMPACTION_KV_MAX = "hbase.hstore.compaction.kv.max";
257   public static final int COMPACTION_KV_MAX_DEFAULT = 10;
258 
259   /** Parameter name for HBase instance root directory */
260   public static final String HBASE_DIR = "hbase.rootdir";
261 
262   /** Parameter name for HBase client IPC pool type */
263   public static final String HBASE_CLIENT_IPC_POOL_TYPE = "hbase.client.ipc.pool.type";
264 
265   /** Parameter name for HBase client IPC pool size */
266   public static final String HBASE_CLIENT_IPC_POOL_SIZE = "hbase.client.ipc.pool.size";
267 
268   /** Parameter name for HBase client operation timeout, which overrides RPC timeout */
269   public static final String HBASE_CLIENT_OPERATION_TIMEOUT = "hbase.client.operation.timeout";
270 
271   /** Parameter name for HBase client operation timeout, which overrides RPC timeout */
272   public static final String HBASE_CLIENT_META_OPERATION_TIMEOUT =
273     "hbase.client.meta.operation.timeout";
274 
275   /** Default HBase client operation timeout, which is tantamount to a blocking call */
276   public static final int DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT = Integer.MAX_VALUE;
277 
278   /** Used to construct the name of the log directory for a region server */
279   public static final String HREGION_LOGDIR_NAME = "WALs";
280 
281   /** Used to construct the name of the splitlog directory for a region server */
282   public static final String SPLIT_LOGDIR_NAME = "splitWAL";
283 
284   /** Like the previous, but for old logs that are about to be deleted */
285   public static final String HREGION_OLDLOGDIR_NAME = "oldWALs";
286 
287   public static final String CORRUPT_DIR_NAME = "corrupt";
288 
289   /** Used by HBCK to sideline backup data */
290   public static final String HBCK_SIDELINEDIR_NAME = ".hbck";
291 
292   /** Any artifacts left from migration can be moved here */
293   public static final String MIGRATION_NAME = ".migration";
294 
295   /**
296    * The directory from which co-processor/custom filter jars can be loaded
297    * dynamically by the region servers. This value can be overridden by the
298    * hbase.dynamic.jars.dir config.
299    */
300   public static final String LIB_DIR = "lib";
301 
302   /** Used to construct the name of the compaction directory during compaction */
303   public static final String HREGION_COMPACTIONDIR_NAME = "compaction.dir";
304 
305   /** Conf key for the max file size after which we split the region */
306   public static final String HREGION_MAX_FILESIZE =
307       "hbase.hregion.max.filesize";
308 
309   /** Default maximum file size */
310   public static final long DEFAULT_MAX_FILE_SIZE = 10 * 1024 * 1024 * 1024L;
311 
312   /**
313    * The max number of threads used for opening and closing stores or store
314    * files in parallel
315    */
316   public static final String HSTORE_OPEN_AND_CLOSE_THREADS_MAX =
317     "hbase.hstore.open.and.close.threads.max";
318 
319   /**
320    * The default number for the max number of threads used for opening and
321    * closing stores or store files in parallel
322    */
323   public static final int DEFAULT_HSTORE_OPEN_AND_CLOSE_THREADS_MAX = 1;
324 
325 
326   /** Conf key for the memstore size at which we flush the memstore */
327   public static final String HREGION_MEMSTORE_FLUSH_SIZE =
328       "hbase.hregion.memstore.flush.size";
329 
330   public static final String HREGION_EDITS_REPLAY_SKIP_ERRORS =
331       "hbase.hregion.edits.replay.skip.errors";
332 
333   public static final boolean DEFAULT_HREGION_EDITS_REPLAY_SKIP_ERRORS =
334       false;
335 
336   /** Maximum value length, enforced on KeyValue construction */
337   public static final int MAXIMUM_VALUE_LENGTH = Integer.MAX_VALUE - 1;
338 
339   /** name of the file for unique cluster ID */
340   public static final String CLUSTER_ID_FILE_NAME = "hbase.id";
341 
342   /** Default value for cluster ID */
343   public static final String CLUSTER_ID_DEFAULT = "default-cluster";
344 
345   // Always store the location of the root table's HRegion.
346   // This HRegion is never split.
347 
348   // region name = table + startkey + regionid. This is the row key.
349   // each row in the root and meta tables describes exactly 1 region
350   // Do we ever need to know all the information that we are storing?
351 
352   // Note that the name of the root table starts with "-" and the name of the
353   // meta table starts with "." Why? it's a trick. It turns out that when we
354   // store region names in memory, we use a SortedMap. Since "-" sorts before
355   // "." (and since no other table name can start with either of these
356   // characters, the root region will always be the first entry in such a Map,
357   // followed by all the meta regions (which will be ordered by their starting
358   // row key as well), followed by all user tables. So when the Master is
359   // choosing regions to assign, it will always choose the root region first,
360   // followed by the meta regions, followed by user regions. Since the root
361   // and meta regions always need to be on-line, this ensures that they will
362   // be the first to be reassigned if the server(s) they are being served by
363   // should go down.
364 
365 
366   /** The hbase:meta table's name. */
367   @Deprecated  // for compat from 0.94 -> 0.96.
368   public static final byte[] META_TABLE_NAME = TableName.META_TABLE_NAME.getName();
369 
370   public static final String BASE_NAMESPACE_DIR = "data";
371 
372   /** delimiter used between portions of a region name */
373   public static final int META_ROW_DELIMITER = ',';
374 
375   /** The catalog family as a string*/
376   public static final String CATALOG_FAMILY_STR = "info";
377 
378   /** The catalog family */
379   public static final byte [] CATALOG_FAMILY = Bytes.toBytes(CATALOG_FAMILY_STR);
380 
381   /** The RegionInfo qualifier as a string */
382   public static final String REGIONINFO_QUALIFIER_STR = "regioninfo";
383 
384   /** The regioninfo column qualifier */
385   public static final byte [] REGIONINFO_QUALIFIER = Bytes.toBytes(REGIONINFO_QUALIFIER_STR);
386 
387   /** The server column qualifier */
388   public static final byte [] SERVER_QUALIFIER = Bytes.toBytes("server");
389 
390   /** The startcode column qualifier */
391   public static final byte [] STARTCODE_QUALIFIER = Bytes.toBytes("serverstartcode");
392 
393   /** The open seqnum column qualifier */
394   public static final byte [] SEQNUM_QUALIFIER = Bytes.toBytes("seqnumDuringOpen");
395 
396   /** The lower-half split region column qualifier */
397   public static final byte [] SPLITA_QUALIFIER = Bytes.toBytes("splitA");
398 
399   /** The upper-half split region column qualifier */
400   public static final byte [] SPLITB_QUALIFIER = Bytes.toBytes("splitB");
401 
402   /** The lower-half merge region column qualifier */
403   public static final byte[] MERGEA_QUALIFIER = Bytes.toBytes("mergeA");
404 
405   /** The upper-half merge region column qualifier */
406   public static final byte[] MERGEB_QUALIFIER = Bytes.toBytes("mergeB");
407 
408   /**
409    * The meta table version column qualifier.
410    * We keep current version of the meta table in this column in <code>-ROOT-</code>
411    * table: i.e. in the 'info:v' column.
412    */
413   public static final byte [] META_VERSION_QUALIFIER = Bytes.toBytes("v");
414 
415   /**
416    * The current version of the meta table.
417    * - pre-hbase 0.92.  There is no META_VERSION column in the root table
418    * in this case. The meta has HTableDescriptor serialized into the HRegionInfo;
419    * - version 0 is 0.92 and 0.94. Meta data has serialized HRegionInfo's using
420    * Writable serialization, and HRegionInfo's does not contain HTableDescriptors.
421    * - version 1 for 0.96+ keeps HRegionInfo data structures, but changes the
422    * byte[] serialization from Writables to Protobuf.
423    * See HRegionInfo.VERSION
424    */
425   public static final short META_VERSION = 1;
426 
427   // Other constants
428 
429   /**
430    * An empty instance.
431    */
432   public static final byte [] EMPTY_BYTE_ARRAY = new byte [0];
433 
434   /**
435    * Used by scanners, etc when they want to start at the beginning of a region
436    */
437   public static final byte [] EMPTY_START_ROW = EMPTY_BYTE_ARRAY;
438 
439   /**
440    * Last row in a table.
441    */
442   public static final byte [] EMPTY_END_ROW = EMPTY_START_ROW;
443 
444   /**
445     * Used by scanners and others when they're trying to detect the end of a
446     * table
447     */
448   public static final byte [] LAST_ROW = EMPTY_BYTE_ARRAY;
449 
450   /**
451    * Max length a row can have because of the limitation in TFile.
452    */
453   public static final int MAX_ROW_LENGTH = Short.MAX_VALUE;
454 
455   /**
456    * Timestamp to use when we want to refer to the latest cell.
457    * This is the timestamp sent by clients when no timestamp is specified on
458    * commit.
459    */
460   public static final long LATEST_TIMESTAMP = Long.MAX_VALUE;
461 
462   /**
463    * Timestamp to use when we want to refer to the oldest cell.
464    */
465   public static final long OLDEST_TIMESTAMP = Long.MIN_VALUE;
466 
467   /**
468    * LATEST_TIMESTAMP in bytes form
469    */
470   public static final byte [] LATEST_TIMESTAMP_BYTES = {
471     // big-endian
472     (byte) (LATEST_TIMESTAMP >>> 56),
473     (byte) (LATEST_TIMESTAMP >>> 48),
474     (byte) (LATEST_TIMESTAMP >>> 40),
475     (byte) (LATEST_TIMESTAMP >>> 32),
476     (byte) (LATEST_TIMESTAMP >>> 24),
477     (byte) (LATEST_TIMESTAMP >>> 16),
478     (byte) (LATEST_TIMESTAMP >>> 8),
479     (byte) LATEST_TIMESTAMP,
480   };
481 
482   /**
483    * Define for 'return-all-versions'.
484    */
485   public static final int ALL_VERSIONS = Integer.MAX_VALUE;
486 
487   /**
488    * Unlimited time-to-live.
489    */
490 //  public static final int FOREVER = -1;
491   public static final int FOREVER = Integer.MAX_VALUE;
492 
493   /**
494    * Seconds in a week
495    */
496   public static final int WEEK_IN_SECONDS = 7 * 24 * 3600;
497 
498   //TODO: although the following are referenced widely to format strings for
499   //      the shell. They really aren't a part of the public API. It would be
500   //      nice if we could put them somewhere where they did not need to be
501   //      public. They could have package visibility
502   public static final String NAME = "NAME";
503   public static final String VERSIONS = "VERSIONS";
504   public static final String IN_MEMORY = "IN_MEMORY";
505   public static final String METADATA = "METADATA";
506   public static final String CONFIGURATION = "CONFIGURATION";
507 
508   /**
509    * Retrying we multiply hbase.client.pause setting by what we have in this array until we
510    * run out of array items.  Retries beyond this use the last number in the array.  So, for
511    * example, if hbase.client.pause is 1 second, and maximum retries count
512    * hbase.client.retries.number is 10, we will retry at the following intervals:
513    * 1, 2, 3, 5, 10, 20, 40, 100, 100, 100.
514    * With 100ms, a back-off of 200 means 20s
515    */
516   public static int RETRY_BACKOFF[] = { 1, 2, 3, 5, 10, 20, 40, 100, 100, 100, 100, 200, 200 };
517 
518   public static final String REGION_IMPL = "hbase.hregion.impl";
519 
520   /** modifyTable op for replacing the table descriptor */
521   public static enum Modify {
522     CLOSE_REGION,
523     TABLE_COMPACT,
524     TABLE_FLUSH,
525     TABLE_MAJOR_COMPACT,
526     TABLE_SET_HTD,
527     TABLE_SPLIT
528   }
529 
530   /**
531    * Scope tag for locally scoped data.
532    * This data will not be replicated.
533    */
534   public static final int REPLICATION_SCOPE_LOCAL = 0;
535 
536   /**
537    * Scope tag for globally scoped data.
538    * This data will be replicated to all peers.
539    */
540   public static final int REPLICATION_SCOPE_GLOBAL = 1;
541 
542   /**
543    * Default cluster ID, cannot be used to identify a cluster so a key with
544    * this value means it wasn't meant for replication.
545    */
546   public static final UUID DEFAULT_CLUSTER_ID = new UUID(0L,0L);
547 
548     /**
549      * Parameter name for maximum number of bytes returned when calling a
550      * scanner's next method.
551      */
552   public static String HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE_KEY = "hbase.client.scanner.max.result.size";
553 
554   /**
555    * Maximum number of bytes returned when calling a scanner's next method.
556    * Note that when a single row is larger than this limit the row is still
557    * returned completely.
558    *
559    * The default value is unlimited.
560    */
561   public static long DEFAULT_HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE = Long.MAX_VALUE;
562 
563   /**
564    * Parameter name for client pause value, used mostly as value to wait
565    * before running a retry of a failed get, region lookup, etc.
566    */
567   public static String HBASE_CLIENT_PAUSE = "hbase.client.pause";
568 
569   /**
570    * Default value of {@link #HBASE_CLIENT_PAUSE}.
571    */
572   public static long DEFAULT_HBASE_CLIENT_PAUSE = 100;
573 
574   /**
575    * The maximum number of concurrent connections the client will maintain.
576    */
577   public static final String HBASE_CLIENT_MAX_TOTAL_TASKS = "hbase.client.max.total.tasks";
578 
579   /**
580    * Default value of {@link #HBASE_CLIENT_MAX_TOTAL_TASKS}.
581    */
582   public static final int DEFAULT_HBASE_CLIENT_MAX_TOTAL_TASKS = 100;
583 
584   /**
585    * The maximum number of concurrent connections the client will maintain to a single
586    * RegionServer.
587    */
588   public static final String HBASE_CLIENT_MAX_PERSERVER_TASKS = "hbase.client.max.perserver.tasks";
589 
590   /**
591    * Default value of {@link #HBASE_CLIENT_MAX_PERSERVER_TASKS}.
592    */
593   public static final int DEFAULT_HBASE_CLIENT_MAX_PERSERVER_TASKS = 2;
594 
595   /**
596    * The maximum number of concurrent connections the client will maintain to a single
597    * Region.
598    */
599   public static final String HBASE_CLIENT_MAX_PERREGION_TASKS = "hbase.client.max.perregion.tasks";
600 
601   /**
602    * Default value of {@link #HBASE_CLIENT_MAX_PERREGION_TASKS}.
603    */
604   public static final int DEFAULT_HBASE_CLIENT_MAX_PERREGION_TASKS = 1;
605 
606   /**
607    * Parameter name for server pause value, used mostly as value to wait before
608    * running a retry of a failed operation.
609    */
610   public static String HBASE_SERVER_PAUSE = "hbase.server.pause";
611 
612   /**
613    * Default value of {@link #HBASE_SERVER_PAUSE}.
614    */
615   public static int DEFAULT_HBASE_SERVER_PAUSE = 1000;
616 
617   /**
618    * Parameter name for maximum retries, used as maximum for all retryable
619    * operations such as fetching of the root region from root region server,
620    * getting a cell's value, starting a row update, etc.
621    */
622   public static String HBASE_CLIENT_RETRIES_NUMBER = "hbase.client.retries.number";
623 
624   /**
625    * Default value of {@link #HBASE_CLIENT_RETRIES_NUMBER}.
626    */
627   public static int DEFAULT_HBASE_CLIENT_RETRIES_NUMBER = 31;
628 
629   /**
630    * Parameter name for client prefetch limit, used as the maximum number of regions
631    * info that will be prefetched.
632    */
633   public static String HBASE_CLIENT_PREFETCH_LIMIT = "hbase.client.prefetch.limit";
634 
635   /**
636    * Default value of {@link #HBASE_CLIENT_PREFETCH_LIMIT}.
637    */
638   public static int DEFAULT_HBASE_CLIENT_PREFETCH_LIMIT = 10;
639 
640   /**
641    * Parameter name to set the default scanner caching for all clients.
642    */
643   public static String HBASE_CLIENT_SCANNER_CACHING = "hbase.client.scanner.caching";
644 
645   /**
646    * Default value for {@link #HBASE_CLIENT_SCANNER_CACHING}
647    */
648   public static int DEFAULT_HBASE_CLIENT_SCANNER_CACHING = 100;
649 
650   /**
651    * Parameter name for number of rows that will be fetched when calling next on
652    * a scanner if it is not served from memory. Higher caching values will
653    * enable faster scanners but will eat up more memory and some calls of next
654    * may take longer and longer times when the cache is empty.
655    */
656   public static String HBASE_META_SCANNER_CACHING = "hbase.meta.scanner.caching";
657 
658   /**
659    * Default value of {@link #HBASE_META_SCANNER_CACHING}.
660    */
661   public static int DEFAULT_HBASE_META_SCANNER_CACHING = 100;
662 
663   /**
664    * Parameter name for unique identifier for this {@link org.apache.hadoop.conf.Configuration}
665    * instance. If there are two or more {@link org.apache.hadoop.conf.Configuration} instances that,
666    * for all intents and purposes, are the same except for their instance ids, then they will not be
667    * able to share the same org.apache.hadoop.hbase.client.HConnection instance. On the other hand,
668    * even if the instance ids are the same, it could result in non-shared
669    * org.apache.hadoop.hbase.client.HConnection instances if some of the other connection parameters
670    * differ.
671    */
672   public static String HBASE_CLIENT_INSTANCE_ID = "hbase.client.instance.id";
673 
674   /**
675    * The client scanner timeout period in milliseconds.
676    */
677   public static String HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD = "hbase.client.scanner.timeout.period";
678 
679   /**
680    * Use {@link #HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD} instead.
681    * @deprecated This config option is deprecated. Will be removed at later releases after 0.96.
682    */
683   @Deprecated
684   public static String HBASE_REGIONSERVER_LEASE_PERIOD_KEY =
685       "hbase.regionserver.lease.period";
686 
687   /**
688    * Default value of {@link #HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD}.
689    */
690   public static int DEFAULT_HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD = 60000;
691 
692   /**
693    * timeout for each RPC
694    */
695   public static String HBASE_RPC_TIMEOUT_KEY = "hbase.rpc.timeout";
696 
697   /**
698    * Default value of {@link #HBASE_RPC_TIMEOUT_KEY}
699    */
700   public static int DEFAULT_HBASE_RPC_TIMEOUT = 60000;
701 
702   /**
703    * timeout for short operation RPC
704    */
705   public static String HBASE_RPC_SHORTOPERATION_TIMEOUT_KEY = "hbase.rpc.shortoperation.timeout";
706 
707   /**
708    * Default value of {@link #HBASE_RPC_SHORTOPERATION_TIMEOUT_KEY}
709    */
710   public static int DEFAULT_HBASE_RPC_SHORTOPERATION_TIMEOUT = 10000;
711 
712   /**
713    * Value indicating the server name was saved with no sequence number.
714    */
715   public static final long NO_SEQNUM = -1;
716 
717 
718   /*
719    * cluster replication constants.
720    */
721   public static final String
722       REPLICATION_ENABLE_KEY = "hbase.replication";
723   public static final boolean
724       REPLICATION_ENABLE_DEFAULT = true;
725   public static final String
726       REPLICATION_SOURCE_SERVICE_CLASSNAME = "hbase.replication.source.service";
727   public static final String
728       REPLICATION_SINK_SERVICE_CLASSNAME = "hbase.replication.sink.service";
729   public static final String REPLICATION_SERVICE_CLASSNAME_DEFAULT =
730     "org.apache.hadoop.hbase.replication.regionserver.Replication";
731 
732   /** HBCK special code name used as server name when manipulating ZK nodes */
733   public static final String HBCK_CODE_NAME = "HBCKServerName";
734 
735   public static final String KEY_FOR_HOSTNAME_SEEN_BY_MASTER =
736     "hbase.regionserver.hostname.seen.by.master";
737 
738   public static final String HBASE_MASTER_LOGCLEANER_PLUGINS =
739       "hbase.master.logcleaner.plugins";
740 
741   public static final String HBASE_REGION_SPLIT_POLICY_KEY =
742     "hbase.regionserver.region.split.policy";
743 
744   /**
745    * Configuration key for the size of the block cache
746    */
747   public static final String HFILE_BLOCK_CACHE_SIZE_KEY =
748     "hfile.block.cache.size";
749 
750   public static final float HFILE_BLOCK_CACHE_SIZE_DEFAULT = 0.25f;
751 
752   /*
753     * Minimum percentage of free heap necessary for a successful cluster startup.
754     */
755   public static final float HBASE_CLUSTER_MINIMUM_MEMORY_THRESHOLD = 0.2f;
756 
757   public static final Pattern CP_HTD_ATTR_KEY_PATTERN = Pattern.compile
758       ("^coprocessor\\$([0-9]+)$", Pattern.CASE_INSENSITIVE);
759   public static final Pattern CP_HTD_ATTR_VALUE_PATTERN =
760       Pattern.compile("(^[^\\|]*)\\|([^\\|]+)\\|[\\s]*([\\d]*)[\\s]*(\\|.*)?$");
761 
762   public static final String CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN = "[^=,]+";
763   public static final String CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN = "[^,]+";
764   public static final Pattern CP_HTD_ATTR_VALUE_PARAM_PATTERN = Pattern.compile(
765       "(" + CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN + ")=(" +
766       CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN + "),?");
767 
768   /** The delay when re-trying a socket operation in a loop (HBASE-4712) */
769   public static final int SOCKET_RETRY_WAIT_MS = 200;
770 
771   /** Host name of the local machine */
772   public static final String LOCALHOST = "localhost";
773 
774   /**
775    * If this parameter is set to true, then hbase will read
776    * data and then verify checksums. Checksum verification
777    * inside hdfs will be switched off.  However, if the hbase-checksum
778    * verification fails, then it will switch back to using
779    * hdfs checksums for verifiying data that is being read from storage.
780    *
781    * If this parameter is set to false, then hbase will not
782    * verify any checksums, instead it will depend on checksum verification
783    * being done in the hdfs client.
784    */
785   public static final String HBASE_CHECKSUM_VERIFICATION =
786       "hbase.regionserver.checksum.verify";
787 
788   public static final String LOCALHOST_IP = "127.0.0.1";
789 
790   /** Conf key that enables unflushed WAL edits directly being replayed to region servers */
791   public static final String DISTRIBUTED_LOG_REPLAY_KEY = "hbase.master.distributed.log.replay";
792   public static final boolean DEFAULT_DISTRIBUTED_LOG_REPLAY_CONFIG = false;
793   public static final String DISALLOW_WRITES_IN_RECOVERING =
794       "hbase.regionserver.disallow.writes.when.recovering";
795   public static final boolean DEFAULT_DISALLOW_WRITES_IN_RECOVERING_CONFIG = false;
796 
797   /** Conf key that specifies timeout value to wait for a region ready */
798   public static final String LOG_REPLAY_WAIT_REGION_TIMEOUT =
799       "hbase.master.log.replay.wait.region.timeout";
800 
801   /**
802    * The name of the configuration parameter that specifies
803    * the number of bytes in a newly created checksum chunk.
804    */
805   public static final String BYTES_PER_CHECKSUM =
806       "hbase.hstore.bytes.per.checksum";
807 
808   /**
809    * The name of the configuration parameter that specifies
810    * the name of an algorithm that is used to compute checksums
811    * for newly created blocks.
812    */
813   public static final String CHECKSUM_TYPE_NAME =
814       "hbase.hstore.checksum.algorithm";
815 
816   /** Enable file permission modification from standard hbase */
817   public static final String ENABLE_DATA_FILE_UMASK = "hbase.data.umask.enable";
818   /** File permission umask to use when creating hbase data files */
819   public static final String DATA_FILE_UMASK_KEY = "hbase.data.umask";
820 
821   /** Configuration name of HLog Compression */
822   public static final String ENABLE_WAL_COMPRESSION =
823     "hbase.regionserver.wal.enablecompression";
824 
825   /** Region in Transition metrics threshold time */
826   public static final String METRICS_RIT_STUCK_WARNING_THRESHOLD="hbase.metrics.rit.stuck.warning.threshold";
827 
828   public static final String LOAD_BALANCER_SLOP_KEY = "hbase.regions.slop";
829 
830   /**
831    * The byte array represents for NO_NEXT_INDEXED_KEY;
832    * The actual value is irrelevant because this is always compared by reference.
833    */
834   public static final byte [] NO_NEXT_INDEXED_KEY = Bytes.toBytes("NO_NEXT_INDEXED_KEY");
835   /** delimiter used between portions of a region name */
836   public static final int DELIMITER = ',';
837   public static final String HBASE_CONFIG_READ_ZOOKEEPER_CONFIG =
838       "hbase.config.read.zookeeper.config";
839   public static final boolean DEFAULT_HBASE_CONFIG_READ_ZOOKEEPER_CONFIG =
840       false;
841 
842   /**
843    * QOS attributes: these attributes are used to demarcate RPC call processing
844    * by different set of handlers. For example, HIGH_QOS tagged methods are
845    * handled by high priority handlers.
846    */
847   public static final int NORMAL_QOS = 0;
848   public static final int QOS_THRESHOLD = 10;
849   public static final int HIGH_QOS = 100;
850   public static final int REPLICATION_QOS = 5; // normal_QOS < replication_QOS < high_QOS
851   public static final int REPLAY_QOS = 6; // REPLICATION_QOS < REPLAY_QOS < high_QOS
852 
853   /** Directory under /hbase where archived hfiles are stored */
854   public static final String HFILE_ARCHIVE_DIRECTORY = "archive";
855 
856   /**
857    * Name of the directory to store all snapshots. See SnapshotDescriptionUtils for
858    * remaining snapshot constants; this is here to keep HConstants dependencies at a minimum and
859    * uni-directional.
860    */
861   public static final String SNAPSHOT_DIR_NAME = ".hbase-snapshot";
862 
863   /* Name of old snapshot directory. See HBASE-8352 for details on why it needs to be renamed */
864   public static final String OLD_SNAPSHOT_DIR_NAME = ".snapshot";
865 
866   /** Temporary directory used for table creation and deletion */
867   public static final String HBASE_TEMP_DIRECTORY = ".tmp";
868 
869   /** Directories that are not HBase table directories */
870   public static final List<String> HBASE_NON_TABLE_DIRS =
871     Collections.unmodifiableList(Arrays.asList(new String[] { HREGION_LOGDIR_NAME,
872       HREGION_OLDLOGDIR_NAME, CORRUPT_DIR_NAME, SPLIT_LOGDIR_NAME,
873       HBCK_SIDELINEDIR_NAME, HFILE_ARCHIVE_DIRECTORY, SNAPSHOT_DIR_NAME, HBASE_TEMP_DIRECTORY,
874       OLD_SNAPSHOT_DIR_NAME, BASE_NAMESPACE_DIR, MIGRATION_NAME, LIB_DIR}));
875 
876   /** Directories that are not HBase user table directories */
877   public static final List<String> HBASE_NON_USER_TABLE_DIRS =
878     Collections.unmodifiableList(Arrays.asList((String[])ArrayUtils.addAll(
879       new String[] { TableName.META_TABLE_NAME.getNameAsString() },
880       HBASE_NON_TABLE_DIRS.toArray())));
881 
882   /** Health script related settings. */
883   public static final String HEALTH_SCRIPT_LOC = "hbase.node.health.script.location";
884   public static final String HEALTH_SCRIPT_TIMEOUT = "hbase.node.health.script.timeout";
885   public static final String HEALTH_CHORE_WAKE_FREQ =
886       "hbase.node.health.script.frequency";
887   public static final long DEFAULT_HEALTH_SCRIPT_TIMEOUT = 60000;
888   /**
889    * The maximum number of health check failures a server can encounter consecutively.
890    */
891   public static final String HEALTH_FAILURE_THRESHOLD =
892       "hbase.node.health.failure.threshold";
893   public static final int DEFAULT_HEALTH_FAILURE_THRESHOLD = 3;
894 
895 
896   /**
897    * Setting to activate, or not, the publication of the status by the master. Default
898    *  notification is by a multicast message.
899    */
900   public static final String STATUS_PUBLISHED = "hbase.status.published";
901   public static final boolean STATUS_PUBLISHED_DEFAULT = false;
902 
903   /**
904    * IP to use for the multicast status messages between the master and the clients.
905    * The default address is chosen as one among others within the ones suitable for multicast
906    * messages.
907    */
908   public static final String STATUS_MULTICAST_ADDRESS = "hbase.status.multicast.address.ip";
909   public static final String DEFAULT_STATUS_MULTICAST_ADDRESS = "226.1.1.3";
910 
911   /**
912    * The address to use for binding the local socket for receiving multicast. Defaults to
913    * 0.0.0.0.
914    * @see <a href="https://issues.apache.org/jira/browse/HBASE-9961">HBASE-9961</a>
915    */
916   public static final String STATUS_MULTICAST_BIND_ADDRESS = "hbase.status.multicast.bind.address.ip";
917   public static final String DEFAULT_STATUS_MULTICAST_BIND_ADDRESS = "0.0.0.0";
918 
919   /**
920    * The port to use for the multicast messages.
921    */
922   public static final String STATUS_MULTICAST_PORT = "hbase.status.multicast.address.port";
923   public static final int DEFAULT_STATUS_MULTICAST_PORT = 60100;
924 
925   /**
926    * The period (in milliseconds) between computing region server point in time metrics
927    */
928   public static final String REGIONSERVER_METRICS_PERIOD = "hbase.regionserver.metrics.period";
929   public static final long DEFAULT_REGIONSERVER_METRICS_PERIOD = 5000;
930 
931   private HConstants() {
932     // Can't be instantiated with this ctor.
933   }
934 }