Github user brianloss commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/83#discussion_r57928954
--- Diff:
server/base/src/main/java/org/apache/accumulo/server/master/balancer/HostRegexTableLoadBalancer.java
---
@@ -0,0 +1,314 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.accumulo.server.master.balancer;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.regex.Pattern;
+
+import org.apache.accumulo.core.client.admin.TableOperations;
+import org.apache.accumulo.core.conf.AccumuloConfiguration;
+import org.apache.accumulo.core.conf.Property;
+import org.apache.accumulo.core.data.impl.KeyExtent;
+import org.apache.accumulo.core.master.thrift.TabletServerStatus;
+import org.apache.accumulo.core.tabletserver.thrift.TabletStats;
+import org.apache.accumulo.server.conf.ServerConfiguration;
+import org.apache.accumulo.server.master.state.TServerInstance;
+import org.apache.accumulo.server.master.state.TabletMigration;
+import org.apache.thrift.TException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This balancer will create pools of tablet servers by grouping tablet
servers that match a regex into the same pool and calling the balancer set on
the table
+ * to balance within the set of matching tablet servers. <br>
+ * Regex properties for this balancer are specified as:<br>
+ *
<b>table.custom.balancer.host.regex.<tablename>=<regex></b><br>
+ * Periodically (default 5m) this balancer will check to see if a tablet
server is hosting tablets that it should not be according to the regex
configuration.
+ * If this occurs then the offending tablets will be reassigned. This
would cover the case where the configuration is changed and the master is
restarted while
+ * the tablet servers are up. To change the out of bounds check time
period, set the following property:<br>
+ * <b>table.custom.balancer.host.regex.oob.period=5m</b><br>
+ * Periodically (default 5m) this balancer will regroup the set of current
tablet servers into pools based on regexes applied to the tserver host names.
This
+ * would cover the case of tservers dying or coming online. To change the
host pool check time period, set the following property: <br>
+ * <b>table.custom.balancer.host.regex.pool.check=5m</b><br>
+ * Regex matching can be based on either the host name (default) or host
ip address. To set this balancer to match the regular expressions to the tablet
server
+ * IP address, then set the following property:<br>
+ * <b>table.custom.balancer.host.regex.is.ip=true</b>
+ *
+ */
+public class HostRegexTableLoadBalancer extends TableLoadBalancer {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(HostRegexTableLoadBalancer.class);
+ public static final String HOST_BALANCER_PREFIX =
Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() + "balancer.host.regex.";
+ public static final String HOST_BALANCER_OOB_CHECK =
Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() +
"balancer.host.regex.oob.period";
+ private static final String HOST_BALANCER_OOB_DEFAULT = "5m";
+ public static final String HOST_BALANCER_POOL_RECHECK_KEY =
Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() +
"balancer.host.regex.pool.check";
+ private static final String HOST_BALANCER_POOL_RECHECK_DEFAULT = "5m";
+ public static final String HOST_BALANCER_REGEX_USING_IPS =
Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() + "balancer.host.regex.is.ip";
+ protected static final String DEFAULT_POOL = "HostTableLoadBalancer.ALL";
+
+ protected long oobCheckMillis =
AccumuloConfiguration.getTimeInMillis(HOST_BALANCER_OOB_DEFAULT);
+ protected long poolRecheckMillis =
AccumuloConfiguration.getTimeInMillis(HOST_BALANCER_POOL_RECHECK_DEFAULT);
+
+ private Map<String,String> tableIdToTableName = null;
+ private Map<String,Pattern> poolNameToRegexPattern = null;
+ private long lastOOBCheck = System.currentTimeMillis();
+ private long lastPoolRecheck = 0;
+ private boolean isIpBasedRegex = false;
+ private Map<String,SortedMap<TServerInstance,TabletServerStatus>> pools
= new HashMap<String,SortedMap<TServerInstance,TabletServerStatus>>();
+
+ /**
+ * Group the set of current tservers by pool name. Tservers that don't
match a regex are put into a default ppol.
+ *
+ * @param current
+ * map of current tservers
+ * @return current servers grouped by pool name, if not a match it is
put into a default pool.
+ */
+ protected synchronized
Map<String,SortedMap<TServerInstance,TabletServerStatus>>
splitCurrentByRegex(SortedMap<TServerInstance,TabletServerStatus> current) {
+ if ((System.currentTimeMillis() - lastPoolRecheck) >
poolRecheckMillis) {
+ Map<String,SortedMap<TServerInstance,TabletServerStatus>> newPools =
new HashMap<String,SortedMap<TServerInstance,TabletServerStatus>>();
+ for (Entry<TServerInstance,TabletServerStatus> e :
current.entrySet()) {
+ String tableName = getPoolNameForHost(e.getKey().host());
+ if (!newPools.containsKey(tableName)) {
+ newPools.put(tableName, new
TreeMap<TServerInstance,TabletServerStatus>());
+ }
+ newPools.get(tableName).put(e.getKey(), e.getValue());
+ }
+ // Ensure that no host is in more than one pool
+ // TODO: I'm not sure that I need to check for disjoint as the call
to getPoolNameForHost checks for more than one match
+ boolean error = false;
+ for (SortedMap<TServerInstance,TabletServerStatus> s1 :
newPools.values()) {
--- End diff --
This nested loop is doing a lot more disjoint checks than need to be done.
You could change the inner loop to iterate over a tailMap starting from the
current outer loop value to get rid of the dups.
That being said, I can also think of cases where you might actually want
disjoint pools. For example, one pool could be for "archive" data which is
large and not accessed very often, so you want to spread it across all
tservers. Then other pools, for hot tables would be on subsets of the tservers.
To support this would mean some re-architecting of the code since the check
would need to be get pool for host and table name.
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