Key Value Server
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Orient Key/Value Server (KV-Server from now) has been built on top of Orient Document Database. The KV-Server is a multi-thread Java application that listen commands on a TCP/IP socket at the port 2431. The port can be changed in the configuration file.
Orient KV-Server groups key/value pairs inside buckets. If you come from the Relational DBMS world and you'd like to know how to use a Key/Value paradigm in place of the classic Relational one, take a look to the "Bucket/Key/Value paradigm as replacement of the Relational DBMS".
All the entries are grouped in Buckets. Buckets are containers of entries. Using different buckets you can separate logically your entries in seperate containers.
Orient Key/Value Server scales out very well in a cluster with thousands of running machines: Orient will divide the load among all the nodes. Cluster, by default, works in auto-discovery mode: when a node starts it attaches itself to the cluster if any. When a node goes down the cluster auto rebalances itself.
Orient uses Hazelcast to handle the partitioned cluster among nodes. In the partitioned version Orient delegates to Hazelcast all the management of the distributed Map. Hazelcast envolves the OrientDB engine in these conditions:
- When an entry is not found, it searches the key in the OrientDB.
- When a new entry is created, it saves the entry also in the OrientDB. The write is synchronous.
- When an entry is updated, it saves the entry also in the OrientDB. The write is synchronous.
- When an entry is deleted, it deletes the entry also in the OrientDB. The delete is synchronous.
Execute the script bin/orient-kv.sh (or bin/orient-kv.bat in MS Windows systems). If the port 2431 is busy the next one will be taken. By default the range is 2431-2440 but you can change it in configuration.
Execute the script bin/orient-kv-partition.sh (or bin/orient-kv-partition.bat in MS Windows systems). If the port 2431 is busy the next one will be taken. By default the range is 2431-2440 but you can change it in configuration.
During the start, the KV-Server searches for an available cluster using the configuration setted. If a cluster is found, then it attaches to it and the cluster network is re-configured to use the new server. If no one cluster is available, then a new network cluster is created with a single node until other nodes will attach to it.
CTRL+C or Soft kill of the process to be sure that the opened databases close softly.
This is the content of the default config/orient-kv.config file contained in the distribution:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<!-- Orient Key/Value Server configuration -->
<orient-server>
<network>
<protocols>
<!-- Default registered protocol. It reads commands using the HTTP protocol and write data
locally -->
<protocol name="http2local" implementation="com.orientechnologies.orient.kv.network.protocol.http.local.ONetworkProtocolHttpKVLocal" />
</protocols>
<listeners>
<!-- Default listener using the HTTP-2-LOCAL protocol bound to localhost, port 2431. If the port is busy
then it will try to acquire the next one up to the 2440. -->
<listener ip-address="127.0.0.1" port-range="2431-2440" protocol="http2local" />
</listeners>
</network>
<storages>
<!-- Default in-memory storage. Data are not saved permanently. -->
<storage name="temp" path="memory:temp"/>
</storages>
<properties>
<!-- Set the asynchronous commit of the maps to the disk in persistent way. It the value is 0
or this property is not defined, the map is written synchronously to the disk.
If the value is major than 0 the maps will be written to disk every VALUE milliseconds -->
<entry name="asynch-commit-delay" value="5000" />
</properties>
</orient-server>This is the content of the default config/orient-kv-partition.config file contained in the distribution:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<!-- Orient Key/Value Server configuration -->
<orient-server>
<handlers>
<handler class="com.orientechnologies.orient.kv.network.protocol.http.partitioned.OServerClusterMember" />
</handlers>
<network>
<protocols>
<!-- Default registered protocol. It reads commands using the HTTP protocol and write data
to the Hazelcast maps. Hazelcast will propagate changes among the nodes depending of Hazelcast
configuration (see hazelcast.xml file). Hazelcast then store clustered maps using the Orient
MapStore implementation. -->
<protocol name="http2partitioned" implementation="com.orientechnologies.orient.kv.network.protocol.http.partitioned.ONetworkProtocolHttpKVPartitioned" />
</protocols>
<listeners>
<!-- Default listener using the HTTP-2-PARTITIONED protocol bound to localhost, port 2431. If the port is busy
then it will try to acquire the next one up to the 2440. -->
<listener ip-address="127.0.0.1" port-range="2431-2440" protocol="http2partitioned" />
</listeners>
</network>
<storages>
<!-- Default in-memory storage. Data are not saved permanently. -->
<storage name="temp" path="memory:temp"/>
</storages>
<properties>
<!-- Set the asynchronous commit of the maps to the disk in persistent way. It the value is 0
or this property is not defined, the map is written synchronously to the disk.
If the value is major than 0 the maps will be written to disk every VALUE milliseconds -->
<entry name="asynch-commit-delay" value="5000" />
</properties>
</orient-server>Handlers between the available ones:
- com.orientechnologies.orient.kv.network.protocol.http.partitioned.OServerClusterMember: manages the server in a cluster
Contains the list of protocols used by the listeners section. The protocols supported today are:
- http2local: the default one for KV-Server
- http2partitioned: the distributed version for KV-Server
- binary: the raw binary protocol used by Orient DB Server
You can configure multiple listeners by adding items under the <listeners> tag and selecting the ip-address and TCP/IP port to bind. The protocol used must be listed in the protocols section.
Contains the list of the configured storages. By default the petshop storage is added for testing purpose. You can use any envirnoment variable in the path such the ORIENT_HOME that points to the Orient installation path if defined otherwise to the root directory where the KV Server starts.
The create database command enlist a new storage in this section.
The cluster configuration, instead, is located in the config/hazelcast.xml file. This is the default one:
<hazelcast>
<group>
<name>orientkv</name>
<password>orient</password>
</group>
<network>
<port auto-increment="true">5701</port>
<join>
<multicast enabled="true">
<multicast-group>224.2.2.3</multicast-group>
<multicast-port>54327</multicast-port>
</multicast>
<tcp-ip enabled="false">
<interface>127.0.0.1</interface>
</tcp-ip>
</join>
<interfaces enabled="true">
<interface>127.0.0.1</interface>
</interfaces>
<symmetric-encryption enabled="false">
<!--
encryption algorithm such as DES/ECB/PKCS5Padding, PBEWithMD5AndDES, AES/CBC/PKCS5Padding, Blowfish, DESede
-->
<algorithm>PBEWithMD5AndDES</algorithm>
<!-- salt value to use when generating the secret key -->
<salt>thesalt</salt>
<!-- pass phrase to use when generating the secret key -->
<password>thepass</password>
<!-- iteration count to use when generating the secret key -->
<iteration-count>19</iteration-count>
</symmetric-encryption>
<asymmetric-encryption enabled="false">
<!-- encryption algorithm -->
<algorithm>RSA/NONE/PKCS1PADDING</algorithm>
<!-- private key password -->
<keyPassword>thekeypass</keyPassword>
<!-- private key alias -->
<keyAlias>local</keyAlias>
<!-- key store type -->
<storeType>JKS</storeType>
<!-- key store password -->
<storePassword>thestorepass</storePassword>
<!-- path to the key store -->
<storePath>keystore</storePath>
</asymmetric-encryption>
</network>
<executor-service>
<core-pool-size>16</core-pool-size>
<max-pool-size>64</max-pool-size>
<keep-alive-seconds>60</keep-alive-seconds>
</executor-service>
<queue name="default">
<!--
Maximum size of the queue. When a JVM's local queue size reaches the maximum, all put/offer operations will get blocked until the
queue size of the JVM goes down below the maximum. Any integer between 0 and Integer.MAX_VALUE. 0 means Integer.MAX_VALUE.
Default is 0.
-->
<max-size-per-jvm>10000</max-size-per-jvm>
<!--
Maximum number of seconds for each item to stay in the queue. Items that are not consumed in <time-to-live-seconds> will
automatically get evicted from the queue. Any integer between 0 and Integer.MAX_VALUE. 0 means infinite. Default is 0.
-->
<time-to-live-seconds>0</time-to-live-seconds>
</queue>
<map name="default">
<map-store enabled="true">
<!--
OrientDB implementation (www.orientechnologies.com). It's very fast, Open Source with Apache 2 license.
-->
<class-name>com.orientechnologies.orient.kv.network.protocol.http.partitioned.OMapLoaderStore</class-name>
<!--
Number of seconds to delay to call the MapStore.store(key, value). If the value is zero then it is write-through so
MapStore.store(key, value) will be called as soon as the entry is updated. Otherwise it is write-behind so updates will be
stored after write-delay-seconds value by calling Hazelcast.storeAll(map). Default value is 0.
-->
<write-delay-seconds>0</write-delay-seconds>
</map-store>
<!--
Number of backups. If 1 is set as the backup-count for example, then all entries of the map will be copied to another JVM for
fail-safety. Valid numbers are 0 (no backup), 1, 2, 3.
-->
<backup-count>1</backup-count>
<!--
Valid values are: NONE (no eviction), LRU (Least Recently Used), LFU (Least Frequently Used). NONE is the default.
-->
<eviction-policy>LRU</eviction-policy>
<!--
Maximum size of the map. When max size is reached, map is evicted based on the policy defined. Any integer between 0 and
Integer.MAX_VALUE. 0 means Integer.MAX_VALUE. Default is 0.
-->
<max-size>5000</max-size>
<!--
When max. size is reached, specified percentage of the map will be evicted. Any integer between 0 and 100. If 25 is set for
example, 25% of the entries will get evicted.
-->
<eviction-percentage>25</eviction-percentage>
</map>
</hazelcast>For more information visit the Hazelcast page.