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https://issues.apache.org/jira/browse/HBASE-15029?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15068991#comment-15068991
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Anoop Sam John commented on HBASE-15029:
----------------------------------------
Values in code can be considered to be latest correct.. What might have
happened is those were the old defaults and later on some Jiras would have
changed them to new values.. And then people might have forgot about the doc
refs. Great if u can give a patch.
cc [~misty]
> A number of inconsistent defaults of configuration parameters
> -------------------------------------------------------------
>
> Key: HBASE-15029
> URL: https://issues.apache.org/jira/browse/HBASE-15029
> Project: HBase
> Issue Type: Bug
> Components: defaults, documentation, hbase
> Affects Versions: 1.1.2
> Reporter: Tianyin Xu
>
> In HBase, a list of default configuration values are inconsistent with what
> is described in the docs ({{hbase-default.xml}}) and the online docs
> (http://hbase.apache.org/book.html#config.files).
> This is really confusing to users like me, as we usually only rely on the
> docs.
> *1. {{hbase.lease.recovery.dfs.timeout}}*
> In hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files], the value is {{64000}},
> while it is {{61000}} in the code,
> {code:title=FSHDFSUtils.java (the only usage)|borderStyle=solid}
> // This should be set to how long it'll take for us to timeout against
> primary datanode if it
> // is dead. We set it to 61 seconds, 1 second than the default
> READ_TIMEOUT in HDFS, the
> // default value for DFS_CLIENT_SOCKET_TIMEOUT_KEY. If recovery is still
> failing after this
> // timeout, then further recovery will take liner backoff with this base,
> to avoid endless
> // preemptions when this value is not properly configured.
> long subsequentPauseBase =
> conf.getLong("hbase.lease.recovery.dfs.timeout", 61 * 1000);
> {code}
> The comments confirm that the value should be {{61000}} rather than
> {{64000}}.
> \\
> \\
> *2. {{hbase.client.retries.number}}*
> In hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files], the value is {{10}},
> while it is {{31}} in the code,
> {code:title=HConstants.java|borderStyle=solid}
> /**
> * Default value of {@link #HBASE_CLIENT_RETRIES_NUMBER}.
> */
> public static final int DEFAULT_HBASE_CLIENT_RETRIES_NUMBER = 31;
> {code}
> All the places using {{hbase.client.retries.number}} take
> {{DEFAULT_HBASE_CLIENT_RETRIES_NUMBER}} as the default value.
> \\
> \\
> *3. {{zookeeper.session.timeout}}*
> In hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files], the value is {{90000}},
> while it is {{180000}} in the code,
> {code:title=HConstants.java|borderStyle=solid}
> /** Configuration key for ZooKeeper session timeout */
> public static final String ZK_SESSION_TIMEOUT = "zookeeper.session.timeout";
> /** Default value for ZooKeeper session timeout */
> public static final int DEFAULT_ZK_SESSION_TIMEOUT = 180 * 1000;
> {code}
> All the places using {{zookeeper.session.timeout}} take
> {{DEFAULT_ZK_SESSION_TIMEOUT}}.
> \\
> \\
> *4. {{hbase.hstore.blockingStoreFiles}}*
> In hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files], the value is {{10}},
> while it is {{7}} in the code,
> {code:title=HStore.java|borderStyle=solid}
> public static final String BLOCKING_STOREFILES_KEY =
> "hbase.hstore.blockingStoreFiles";
> public static final int DEFAULT_BLOCKING_STOREFILE_COUNT = 7;
> {code}
> Same as #3 and #4.
> \\
> \\
> *5. {{hbase.http.max.threads}}*
> In hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files], the value is {{10}},
> while {{10}} is never used in the code.
> The code logic is a little bit complex:
> {code:title=HttpServer.java (the only usage)|borderStyle=solid}
> static final String HTTP_MAX_THREADS = "hbase.http.max.threads";
> ...
> int maxThreads = conf.getInt(HTTP_MAX_THREADS, -1);
> // If HTTP_MAX_THREADS is not configured, QueueThreadPool() will use the
> // default value (currently 250).
> QueuedThreadPool threadPool = maxThreads == -1 ? new QueuedThreadPool()
> : new QueuedThreadPool(maxThreads);
> {code}
> Basically, if the user does not set the value, {{maxThreads}} would be {{-1}}
> which is equavalent to the default value of {{_maxThreads}} in the
> {{QueuedThreadPool}} class (it is {{250}} right now).
> \\
> \\
> *6. {{hbase.ipc.server.callqueue.handler.factor}}*
> In hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files], the value is {{0.1}},
> while it is {{0}} in the code,
> {code:title=SimpleRpcScheduler.java|borderStyle=solid}
> public static final String CALL_QUEUE_HANDLER_FACTOR_CONF_KEY =
> "hbase.ipc.server.callqueue.handler.factor";
> ...
> float callQueuesHandlersFactor =
> conf.getFloat(CALL_QUEUE_HANDLER_FACTOR_CONF_KEY, 0);
> int numCallQueues = Math.max(1, (int)Math.round(handlerCount *
> callQueuesHandlersFactor));
> {code}
> \\
> *7. {{hbase.regionserver.logroll.errors.tolerated}}*
> In hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files],, the value is {{2}},
> while it is {{0}} in the code (i.e., the default is not tolerating any
> error...),
> {code:title=FSHLog.java (the only usage)|borderStyle=solid}
> this.closeErrorsTolerated =
> conf.getInt("hbase.regionserver.logroll.errors.tolerated", 0);
> {code}
> This is really confusing as we suppose to have 2 errors tolerated...
> \\
> \\
> *8. {{hbase.snapshot.enabled}}*
> I'm not really confident for this one. In hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files],, the value is {{true}},
> while it is {{false}} in the code
> {code:title=SnapshotManager.java (the only usage)|borderStyle=solid}
> public static final String HBASE_SNAPSHOT_ENABLED =
> "hbase.snapshot.enabled";
> ...
> boolean snapshotEnabled = conf.getBoolean(HBASE_SNAPSHOT_ENABLED, false);
> {code}
> \\
> *9. {{hbase.online.schema.update.enable}}*
> Again, in both hbase-default.xml and [online
> docs|http://hbase.apache.org/book.html#config.files],, the value is {{true}},
> while it is {{false}} in both {{TableEventHandler}} and
> {{MasterDDLOperationHelper}}:
> {code:title=TableEventHandler.java|borderStyle=solid}
> private boolean isOnlineSchemaChangeAllowed() {
> return this.server.getConfiguration().getBoolean(
> "hbase.online.schema.update.enable", false);
> }
> {code}
> {code:title=MasterDDLOperationHelper.java|borderStyle=solid}
> public static boolean isOnlineSchemaChangeAllowed(final MasterProcedureEnv
> env) {
> return env.getMasterServices().getConfiguration()
> .getBoolean("hbase.online.schema.update.enable", false);
> }
> {code}
> Thanks!
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