Re: problem with the heartbeat interval feature
thanks Hongshun for your response !
Le ven. 17 mai 2024 à 07:51, Hongshun Wang a
écrit :
> Hi Thomas,
>
> In debezium dos says: For the connector to detect and process events from
> a heartbeat table, you must add the table to the PostgreSQL publication
> specified by the publication.name
> <https://debezium.io/documentation/reference/stable/connectors/postgresql.html#postgresql-property-publication-name>
> property.
> If this publication predates your Debezium deployment, the connector uses
> the publications as defined. If the publication is not already configured
> to automatically replicate changes FOR ALL TABLES in the database, you
> must explicitly add the heartbeat table to the publication[2].
>
> Thus, if you want use heart beat in cdc:
>
>1. add a heartbeat table to publication: ALTER PUBLICATION
>** ADD TABLE **;
>2. set heartbeatInterval
>3. add debezium.heartbeat.action.query
>
> <https://debezium.io/documentation/reference/stable/connectors/postgresql.html#postgresql-property-heartbeat-action-query>
> [3]
>
> However, when I use it it CDC, some exception occurs:
>
> Caused by: java.lang.NullPointerException
> at
> io.debezium.heartbeat.HeartbeatFactory.createHeartbeat(HeartbeatFactory.java:55)
> at io.debezium.pipeline.EventDispatcher.(EventDispatcher.java:127)
> at io.debezium.pipeline.EventDispatcher.(EventDispatcher.java:94)
>
>
>
>
> It seems CDC don't add a HeartbeatConnectionProvider when configure
> PostgresEventDispatcher:
>
> //org.apache.flink.cdc.connectors.postgres.source.fetch.PostgresSourceFetchTaskContext#configurethis.postgresDispatcher
> =
> new PostgresEventDispatcher<>(
> dbzConfig,
> topicSelector,
> schema,
> queue,
> dbzConfig.getTableFilters().dataCollectionFilter(),
> DataChangeEvent::new,
> metadataProvider,
> schemaNameAdjuster);
>
>
> In debezium, when PostgresConnectorTask start, it will do it
>
> //io.debezium.connector.postgresql.PostgresConnectorTask#start final
> PostgresEventDispatcher dispatcher = new PostgresEventDispatcher<>(
> connectorConfig,
> topicNamingStrategy,
> schema,
> queue,
> connectorConfig.getTableFilters().dataCollectionFilter(),
> DataChangeEvent::new,
> PostgresChangeRecordEmitter::updateSchema,
> metadataProvider,
> connectorConfig.createHeartbeat(
> topicNamingStrategy,
> schemaNameAdjuster,
> () -> new
> PostgresConnection(connectorConfig.getJdbcConfig(),
> PostgresConnection.CONNECTION_GENERAL),
> exception -> {
> String sqlErrorId = exception.getSQLState();
> switch (sqlErrorId) {
> case "57P01":
> // Postgres error admin_shutdown, see
> https://www.postgresql.org/docs/12/errcodes-appendix.html
>throw new DebeziumException("Could not execute heartbeat
> action query (Error: " + sqlErrorId + ")", exception);
> case "57P03":
> // Postgres error cannot_connect_now,
> see https://www.postgresql.org/docs/12/errcodes-appendix.html
>throw new RetriableException("Could not execute
> heartbeat action query (Error: " + sqlErrorId + ")", exception);
> default:
> break;
> }
> }),
> schemaNameAdjuster,
> signalProcessor);
>
> Thus, I have create a new jira[4] to fix it.
>
>
>
> [1]
> https://nightlies.apache.org/flink/flink-cdc-docs-master/docs/connectors/legacy-flink-cdc-sources/postgres-cdc/
>
> [2]
> https://debezium.io/documentation/reference/stable/connectors/postgresql.html#postgresql-property-heartbeat-interval-ms
>
> [3]
> https://debezium.io/documentation/reference/stable/connectors/postgresql.html#postgresql-property-heartbeat-action-query
>
> [4] https://issues.apache.org/jira/browse/FLINK-35387
>
>
> Best
>
> Hongshun
>
>
problem with the heartbeat interval feature
Hi Flink Community !
I am using :
* Flink
* Flink CDC posgtres Connector
* scala + sbt
versions are :
* orgApacheKafkaVersion = "3.2.3"
* flinkVersion = "1.19.0"
* flinkKafkaVersion = "3.0.2-1.18"
* flinkConnectorPostgresCdcVersion = "3.0.1"
* debeziumVersion = "1.9.8.Final"
* scalaVersion = "2.12.13"
* javaVersion = "11"
the problem
---
I have a problem with the heartbeat interval feature:
* when I am querying PG with `select * from pg_replication_slots;` for
checking if information are updated on each replication slots at defined
interval
* then confirmed_flush_lsn values are never updated
PS: i have other replication slots managed directly with debezium (without
flink) and their confirmed_flush_lsn values are updated correctly (same pg
DB) depending of their own interval
```
slot_name | plugin | slot_type | datoid |
database | temporary | active | active_pid | xmin | catalog_xmin |
restart_lsn | confirmed_flush_lsn
+--+---+---+---+---+++--+--+--+-
slot_table1| pgoutput | logical | 811518778 | the_db
| f | t | 10870 | | 1630392036 |
712/697C0DB8 | 712/697C0DF0
slot_table2| pgoutput | logical | 811518778 | the_db
| f | t | 10894 | | 1630392033 |
712/697AD0A8 | 712/697AD0E0
slot_table3| pgoutput | logical | 811518778 | the_db
| f | t | 10978 | | 1630392034 |
712/697AD0A8 | 712/697AD0A8
```
My setup
I have configured 3 distinct DataStreamSource on 3 pg database tables using
this common method :
```
private def initEntityDataSource(conf: Config, env:
StreamExecutionEnvironment, entityName: String, columnList: String) = {
val dbzProps: Properties = new Properties()
dbzProps.setProperty("column.include.list", columnList)
// "public.tableX.column1,public.tableX.column2"
val postgresIncrementalSource:
PostgresSourceBuilder.PostgresIncrementalSource[String] =
PostgresSourceBuilder.PostgresIncrementalSource.builder()
.hostname(conf.getString("pg.hostname"))
.port(conf.getInt("pg.port"))
.database(conf.getString("pg.database"))
.username(conf.getString("pg.username"))
.password(conf.getString("pg.password"))
.slotName(conf.getString(s"flink.${entityName}.slot_name"))
// slot_tableX
.decodingPluginName("pgoutput")
.includeSchemaChanges(true)
.deserializer(new JsonDebeziumDeserializationSchema())
.closeIdleReaders(true)
.heartbeatInterval(Duration.ofMillis(1)) //
<--// 10 seconds
.connectTimeout(Duration.ofSeconds(10))
// 10 Seconds
.startupOptions(StartupOptions.initial())
.schemaList("public")
.tableList("public." +
conf.getString(s"flink.${entityName}.table_name")) // public.tableX
.debeziumProperties(dbzProps) //
<--// dbzProps
.build()
env.fromSource(postgresIncrementalSource,
WatermarkStrategy.noWatermarks[String](), s"pg-projector-${entityName}")
.setParallelism(1)
}
```
After that I have converted each DataStreamSource into Table
And I join those 3 Table and convert result into a DataStream[Row]
On this new DataStream I do a keyBy for processing a custom
KeyedProcessFunction function
All of this is working fine and do its job
But heartbeat seems to not refresh values into
pg_replication_slots.confirmed_flush_lsn column
PS: I also try this :
1) instead of using the .heartbeatInterval() method to set the value of
interval ... i use debezium properties like this
```
dbzProps.setProperty("heartbeat.interval.ms", "1")// and also
"PT10S"
```
it seems there is no effect with this
2) it seems that debezium needs to create a kafka topic for managing
heartbeat. In theory, If the topic does not exist it will be automaitcally
created
But my kafka server does not authorize this auto creation ... so i create
this topic mannually with this name :
`__flink-heartbeat.postgres_cdc_source`
i also add this dbzProps for setting the good topic prefix
```
dbzProps.setProperty("topic.heartbeat.prefix", "__flink-heartbeat")
```
it seems there is no effect with this too
So ... Do you have any ideas ?
Thanks,
Thomas
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