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Vote thread | - | ||||||||
JIRA | - | ||||||||
https://lists.apache.org/thread/d1owrg8zh77v0xygcpb93fxt0jpjdkb3 | |||||||||
Vote thread | https://lists.apache.org/thread/7jbmg22lnww31sbfdzztwrzgm6bkhjrj | ||||||||
JIRA |
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Release | 1.18.0 | Release | - |
Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).
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draw.io Board Diagram | ||||||||||||||||||||
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There are 6 7 main classes in Flink Jdbc Driver: FlinkDriver, FlinkDataSource, FlinkConnection, FlinkStatement, FlinkResultSet, FlinkDatabaseMetaData and FlinkResultSetMetaData which implement jdbc interface Driver, DataSource, Connection, Statement, ResultSet, DatabaseMetaData and ResultSetMetaData.
- FlinkDriver parses gateway address from url, and creates FlinkConnection
- FlinkDataSource manages connection pool for flink jdbc, it will create specific count of connections and choose one for client directly.
- FlinkConnection creates Executor according to gateway address. When the Connections is closed, it can close the connection with gateway by Executor
- FlinkStatement can get Executor from FlinkConnection, and submit sql query to it. After query is executed, FlinkStatement can get StatementResult from Executor, and create FlinkResultSet
- FlinkResultSet is an iterator, it gets results from StatementResult and return them to users
- FlinkDatabaseMetaData provides meta data of catalogs, databases and tables
- FlinkResultSetMetaData provides meta data of ResultSet such as columns
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User Case
Flink Jdbc Driver module will be packaged into an independent jar file such as flink-table-jdbc-driver-{version}.jar
, which will contains classes of flink jdbc driver and shaded flink classes such as data type. User only need to add jdbc dependency in pom.xml or add the jar in the classpath of external Jdbc Tools such as sqlite.
Code Block | ||
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<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-jdbc-driver</artifactId>
<version>${flink.version}</version>
</dependency> |
More information about Flink Jdbc Driver
|
There're Session
s and Operation
s in SqlGateway
. SqlGateway
will open a Session
for each FlinkConnection
, and then do multiple Operation
s in one Session
. When users create a FlinkConnection
by FlinkDriver
with SqlGateway
, it will open an exist or a new Session
. Any time users want to issue SQL statements to the database, they require a FlinkStatement
instance from FlinkConnection
. Once users have a FlinkStatement
, they can use issue a query. This will return a FlinkResultSet
instance, which contains the entire result. Each operation such as the execution query(Flink job), fetching results in FlinkResultSet
will be an Operation
in the Session
of SqlGateway
.
User Case
Flink Jdbc Driver module will be packaged into an independent jar file such as flink-table-jdbc-driver-{version}.jar
, which will contains classes of flink jdbc driver and shaded flink classes such as data type. User only need to add jdbc dependency in pom.xml or add the jar in the classpath of external Jdbc Tools such as sqlite.
Code Block | ||
---|---|---|
| ||
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-jdbc-driver</artifactId>
<version>${flink.version}</version>
</dependency> |
More information about Flink Jdbc Driver
- Driver Name: org.apache.flink.table.jdbc.FlinkDriver
- Flink Connection URL: Users can use default catalog and database directly, or set them in url. Users can also set custom parameters in url to open the session in SqlGateway with key1=val1&key2=val2&...
- Driver Name: org.apache.flink.table.jdbc.FlinkDriver
- Flink Connection URL: Users can use default catalog and database directly, or set them in url. Users can also set custom parameters in url to open the session in SqlGateway with key1=val1&key2=val2&...
- jdbc:flink://{sql-gateway.host}:{sql-gateway.port}?key1=val1&key2=val2 jdbc:flink://{sql-gateway.host}:{sql-gateway.port}/{catalog name}?key1=val1&key2=val2
- jdbc:flink://{sql-gateway.host}:{sql-gateway.port}?key1=val1&key2=val2
- jdbc:flink://{sql-gateway.host}:{sql-gateway.port}/{catalog name}?key1=val1&key2=val2
- jdbc:flink://{sql-gateway.host}:{sql-gateway.port}//{catalog name}/{database name}?key1=val1&key2=val2
- Currently SqlGateway does not support authentication,
user
andpassword
in connection are invalid. Use Flink Jdbc Driver in Java code
Code Block language java String driverName = "org.apache.flink.table.jdbc.FlinkDriver"; String url = "jdbc:flink://{sql-gateway.host}:{sql-gateway.port}/{catalog name}/{database name}?key1=val1&key2=val2"; Class.forName(driverName); try (Connection connection = DriverManager.getConnection(url)) { try (Statement statement = connection.createStatement()) { try (ResultSet resultSet = statement.execute("SELECT * FROM {Your Table}")) { while (resultSet.hasNext()) { .Do your work ... } } try (ResultSet resultSet } }
- User can also add the
flink-table-jdbc-driver-{version}.jar
to the classpath of external jdbc tools.
Data Types
The following basic flink data types are supported to convert to sql data type in this FLIP, and more types can be supported as needed in the future.
= statement.execute("SELECT * FROM T1 JOIN T2 on T1.id=T2.id ...")) { while (resultSet.hasNext()) { Do your work ... } } } }
- User can also add the
flink-table-jdbc-driver-{version}.jar
to the classpath of external jdbc tools.
Data Types
The following basic flink data types are supported to convert to sql data type in this FLIP, and more types can be supported as needed in the future.
Flink Data Type | Java Sql Data Type | Java Data Type |
CharType/VarCharType | CHAR/VARCHAR | String |
BooleanType | BOOLEAN | |
Flink Data Type | Java Sql Data Type | Java Data Type |
CharType/VarCharType | CHAR/VARCHAR | String |
BooleanType | BOOLEAN | Boolean |
TinyIntType | TINYINT | Byte |
SmallIntType | SMALLINT | Short |
IntType | INTEGER | Int |
BigIntType | BIGINT | Long |
FloatType | FLOAT | Float |
DoubleType | DOUBLE | Double |
DecimalType | DECIMAL | BigDecimal |
BinaryType/VarBinaryType | BINARY/VARBINARY | byte[] |
DateType | DATE | Date |
TimeType | TIME | Time |
TimestampType | TIMESTAMP | Timestamp |
ZonedTimestampType | TIMESTAMP_WITH_TIMEZONE | ZonedDateTime |
LocalZonedTimestampType | TIMESTAMP_LZT(Not in java.sql.Types) | Instant |
ArrayType | ARRAY | Array |
RowType | ROW(Not in java.sql.Types) | Row(Flink Row Data) |
MapType | MAP | Map<K, V> |
Public Interface
There are many methods in Jdbc Driver, while this FLIP only implement the basic methods first and more methods will be implemented later when they are needed.
- Methods in
FlinkDriver
Double | ||
DecimalType | DECIMAL | BigDecimal |
BinaryType/VarBinaryType | BINARY/VARBINARY | byte[] |
DateType | DATE | Date |
TimeType | TIME | Time |
TimestampType | TIMESTAMP | Timestamp |
ZonedTimestampType | TIMESTAMP_WITH_TIMEZONE | OffsetDateTime |
LocalZonedTimestampType | TIMESTAMP_WITH_LOCAL_TIMEZONE | Timestamp |
ArrayType | ARRAY | Array |
RowType | ROW(Not in java.sql.Types) | Row(Flink Row Data) |
MapType | MAP | Map<K, V> |
Currently TIMESTAMP_WITH_LOCAL_TIMEZONE is not exist in java.sql.Types, but it is supported by Flink
. Users can define a field as (f TIMESTAMP(p) WITH LOCAL TIME ZONE)
and set time zone through the connection parameters or dynamic parameters in console by table.local-time-zone
. After that, users can get Timestamp
which will be automatically converted from stored time data into specific Timestamp
according to the given time zone.
Java Sql Interfaces
There are many methods in Jdbc Driver, while this FLIP only implement the basic methods first and more methods will be implemented later when they are needed.
- Methods in
FlinkDriver
Code Block | ||
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/* Jdbc Driver for flink sql gateway. Only Batch Mode queries are supported. If you force to submit streaming queries, you may get unrecognized updates, deletions and other results in FlinkResultSet. */
public class FlinkDriver implements Driver {
/* Connect sql gateway with given url and open/create session with given priperties. */
@Override
public Connection connect(String url, Properties info) throws SQLException;
} |
- Methods in FlinkDataSource
Code Block | ||
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/* Jdbc DataSource manages connections for client, we can support more operations in it in the future. */
public class FlinkDataSource implements DataSource {
/* The max count of connections which the data source holds. */
private int maxActive;
/* Set the url of connection. */
public synchronized void setUrl(String url);
/* Set the driver class name for the source. */
public synchronized void setDriverClassName(String driverClassName);
/* Set the max active connection for the source. */
public synchronized void setMaxActive(int maxActive);
/* Get a connection from data source. */
@Override
public Connection getConnection() throws SQLException;
@Override | ||
Code Block | ||
| ||
/* Jdbc Driver for flink sql gateway */ public class FlinkDriver implements Driver { /* Connect sql gateway with given url and open/create session with given priperties. */ @Override public Connection connectgetConnection(String urlusername, PropertiesString infopassword) throws SQLException; } |
- Methods in
FlinkConnection
...
- Methods in
FlinkResultSet
:FlinkResultSet
only supports fetching data from iteratorStatementResult
, it supports getXXX methods and doesn't support deleting, updating or moving the cursor. Compare withResultSet
, there isgetKind
method inFlinkResultSet
to get theRowKind
of current record.
Code Block | ||
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/* ResultSet for flink jdbc driver. */ public class FlinkResultSet implements ResultSet { /* Get the row kind for the current record ResultSet for flink jdbc driver. Only Batch Mode queries are supported. If you force to submit streaming queries, you may get unrecognized updates, deletions and other results. */ public RowKind getKind(); class FlinkResultSet implements ResultSet { /* Return true if there are more resuts in result iterator. */ @Override public boolean next() throws SQLException; /* Close the fetch result operation. */ @Override public void close() throws SQLException; /* Get different values according to data type and column index. */ @Override public <V> V getXXX(int columnIndex) throws SQLException. /* Get different values according to data type and column name. */ @Override public <V> V getXXX(String columnName) throws SQLException. } |
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When an error occurs, Flink Jdbc Driver mainly throws the following exceptions
SQLState Class | SQLState SubClass | Reason | Exception | Operations |
---|---|---|---|---|
22 | 000 to 02H according to different errors | Description of data conversion error | SQLDataException | Get data error from ResultSet in methods getXXX |
0A | 000 | Specific feature is not supported | SQLFeatureNotSupportedException | All unimplemented methods will throw this exception |
58 | 004 | The exception or error message from Gateway | SQLNonTransientException | Gateway throws an exception or returns an error message when executing the query |
08 | 006 | The session is not exist in Gateway and client need to create new connection to it | SQLNonTransientConnectionException | Gateway is restarted and the client need to create new connection |
We can continue to subdivide and throw different exceptions according to the error information returned by the Gateway in Flink Jdbc Driver in the future
...