DbBackendConfig (flink 1.0-SNAPSHOT API)

java.lang.Object
- org.apache.flink.contrib.streaming.state.DbBackendConfig

All Implemented Interfaces:

Serializable
```
public class DbBackendConfig
extends Object
implements Serializable
```
Configuration object for DbStateBackend, containing information to shard and connect to the databases that will store the state checkpoints.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description
`DbBackendConfig(String dbUserName, String dbUserPassword, List<String> dbShardUrls)` Creates a new sharded database state backend configuration with the given parameters and default `MySqlAdapter`.
`DbBackendConfig(String dbUserName, String dbUserPassword, String dbUrl)` Creates a new database state backend configuration with the given parameters and default `MySqlAdapter`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`ShardedConnection`	`createShardedConnection()` Creates a new `ShardedConnection` using the set parameters.
`DbAdapter`	`getDbAdapter()` Get the `DbAdapter` that will be used to operate on the database during checkpointing.
`String`	`getJDBCDriver()` The class name that should be used to load the JDBC driver using Class.forName(JDBCDriverClass).
`int`	`getKvCacheSize()` The maximum number of key-value pairs stored in one task instance's cache before evicting to the underlying database.
`int`	`getKvStateCompactionFrequency()` Sets how often will automatic compaction be performed on the database to remove old overwritten state changes.
`float`	`getMaxKvCacheEvictFraction()` The maximum fraction of key-value states evicted from the cache if the cache is full.
`int`	`getMaxKvInsertBatchSize()` The maximum number of key-value pairs inserted in the database as one batch operation.
`int`	`getMaxNumberOfSqlRetries()` The number of times each SQL command will be retried on failure.
`int`	`getNumberOfShards()` Number of database shards defined.
`int`	`getNumElementsToEvict()` The number of elements that will be evicted when the cache is full.
`String`	`getShardUrl(int shardIndex)` The url of a specific shard.
`List<String>`	`getShardUrls()` Database shard urls as provided in the constructor.
`int`	`getSleepBetweenSqlRetries()` The number of milliseconds slept between two SQL retries.
`String`	`getUrl()` The url of the first shard.
`String`	`getUserName()` The username used to connect to the database at the given urls.
`String`	`getUserPassword()` The password used to connect to the database at the given url and username.
`void`	`setDbAdapter(DbAdapter adapter)` Set the `DbAdapter` that will be used to operate on the database during checkpointing.
`void`	`setJDBCDriver(String jDBCDriverClassName)` Set the class name that should be used to load the JDBC driver using Class.forName(JDBCDriverClass).
`void`	`setKvCacheSize(int size)` Set the maximum number of key-value pairs stored in one task instance's cache before evicting to the underlying database.
`void`	`setKvStateCompactionFrequency(int compactEvery)` Sets how often will automatic compaction be performed on the database to remove old overwritten state changes.
`void`	`setMaxKvCacheEvictFraction(float fraction)` Sets the maximum fraction of key-value states evicted from the cache if the cache is full.
`void`	`setMaxKvInsertBatchSize(int size)` Set the maximum number of key-value pairs inserted in the database as one batch operation.
`void`	`setMaxNumberOfSqlRetries(int maxNumberOfSqlRetries)` Sets the number of times each SQL command will be retried on failure.
`void`	`setPartitioner(ShardedConnection.Partitioner partitioner)` Sets the partitioner used to assign keys to different database shards
`void`	`setSleepBetweenSqlRetries(int sleepBetweenSqlRetries)` Sets the number of milliseconds slept between two SQL retries.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - DbBackendConfig
```
public DbBackendConfig(String dbUserName,
                       String dbUserPassword,
                       List<String> dbShardUrls)
```
    Creates a new sharded database state backend configuration with the given parameters and default MySqlAdapter.
    
    Parameters:
    
    dbUserName - The username used to connect to the database at the given url.
    
    dbUserPassword - The password used to connect to the database at the given url and username.
    
    dbShardUrls - The list of JDBC urls of the databases that will be used as shards for the state backend. Sharding of the state will happen based on the subtask index of the given task.
  - DbBackendConfig
```
public DbBackendConfig(String dbUserName,
                       String dbUserPassword,
                       String dbUrl)
```
    Creates a new database state backend configuration with the given parameters and default MySqlAdapter.
    
    Parameters:
    
    dbUserName - The username used to connect to the database at the given url.
    
    dbUserPassword - The password used to connect to the database at the given url and username.
    
    dbUrl - The JDBC url of the database for example "jdbc:mysql://localhost:3306/flinkdb".
- Method Detail
  - getUserName
```
public String getUserName()
```
    The username used to connect to the database at the given urls.
  - getUserPassword
```
public String getUserPassword()
```
    The password used to connect to the database at the given url and username.
  - getNumberOfShards
```
public int getNumberOfShards()
```
    Number of database shards defined.
  - getShardUrls
```
public List<String> getShardUrls()
```
    Database shard urls as provided in the constructor.
  - getUrl
```
public String getUrl()
```
    The url of the first shard.
  - getShardUrl
```
public String getShardUrl(int shardIndex)
```
    The url of a specific shard.
  - getDbAdapter
```
public DbAdapter getDbAdapter()
```
    Get the DbAdapter that will be used to operate on the database during checkpointing.
  - setDbAdapter
```
public void setDbAdapter(DbAdapter adapter)
```
    Set the DbAdapter that will be used to operate on the database during checkpointing.
  - getJDBCDriver
```
public String getJDBCDriver()
```
    The class name that should be used to load the JDBC driver using Class.forName(JDBCDriverClass).
  - setJDBCDriver
```
public void setJDBCDriver(String jDBCDriverClassName)
```
    Set the class name that should be used to load the JDBC driver using Class.forName(JDBCDriverClass).
  - getKvCacheSize
```
public int getKvCacheSize()
```
    The maximum number of key-value pairs stored in one task instance's cache before evicting to the underlying database.
  - setKvCacheSize
```
public void setKvCacheSize(int size)
```
    Set the maximum number of key-value pairs stored in one task instance's cache before evicting to the underlying database. When the cache is full the N least recently used keys will be evicted to the database, where N = maxKvEvictFraction*KvCacheSize.
  - getMaxKvInsertBatchSize
```
public int getMaxKvInsertBatchSize()
```
    The maximum number of key-value pairs inserted in the database as one batch operation.
  - setMaxKvInsertBatchSize
```
public void setMaxKvInsertBatchSize(int size)
```
    Set the maximum number of key-value pairs inserted in the database as one batch operation.
  - setMaxKvCacheEvictFraction
```
public void setMaxKvCacheEvictFraction(float fraction)
```
    Sets the maximum fraction of key-value states evicted from the cache if the cache is full.
  - getMaxKvCacheEvictFraction
```
public float getMaxKvCacheEvictFraction()
```
    The maximum fraction of key-value states evicted from the cache if the cache is full.
  - getNumElementsToEvict
```
public int getNumElementsToEvict()
```
    The number of elements that will be evicted when the cache is full.
  - setKvStateCompactionFrequency
```
public void setKvStateCompactionFrequency(int compactEvery)
```
    Sets how often will automatic compaction be performed on the database to remove old overwritten state changes. The frequency is set in terms of number of successful checkpoints between two compactions and should take the state size and checkpoint frequency into account.
    By default automatic compaction is turned off.
  - getKvStateCompactionFrequency
```
public int getKvStateCompactionFrequency()
```
    Sets how often will automatic compaction be performed on the database to remove old overwritten state changes. The frequency is set in terms of number of successful checkpoints between two compactions and should take the state size and checkpoint frequency into account.
    By default automatic compaction is turned off.
  - getMaxNumberOfSqlRetries
```
public int getMaxNumberOfSqlRetries()
```
    The number of times each SQL command will be retried on failure.
  - setMaxNumberOfSqlRetries
```
public void setMaxNumberOfSqlRetries(int maxNumberOfSqlRetries)
```
    Sets the number of times each SQL command will be retried on failure.
  - getSleepBetweenSqlRetries
```
public int getSleepBetweenSqlRetries()
```
    The number of milliseconds slept between two SQL retries. The actual sleep time will be chosen randomly between 1 and the given time.
  - setSleepBetweenSqlRetries
```
public void setSleepBetweenSqlRetries(int sleepBetweenSqlRetries)
```
    Sets the number of milliseconds slept between two SQL retries. The actual sleep time will be chosen randomly between 1 and the given time.
  - setPartitioner
```
public void setPartitioner(ShardedConnection.Partitioner partitioner)
```
    Sets the partitioner used to assign keys to different database shards
  - createShardedConnection
```
public ShardedConnection createShardedConnection()
                                          throws SQLException
```
    Creates a new ShardedConnection using the set parameters.
    
    Throws:
    
    SQLException

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Class DbBackendConfig

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

DbBackendConfig

DbBackendConfig

Method Detail

getUserName

getUserPassword

getNumberOfShards

getShardUrls

getUrl

getShardUrl

getDbAdapter

setDbAdapter

getJDBCDriver

setJDBCDriver

getKvCacheSize

setKvCacheSize

getMaxKvInsertBatchSize

setMaxKvInsertBatchSize

setMaxKvCacheEvictFraction

getMaxKvCacheEvictFraction

getNumElementsToEvict

setKvStateCompactionFrequency

getKvStateCompactionFrequency

getMaxNumberOfSqlRetries

setMaxNumberOfSqlRetries

getSleepBetweenSqlRetries

setSleepBetweenSqlRetries

setPartitioner

createShardedConnection

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