Hi Yan,
there are no table source interfaces that allow for creating a retract
stream directly yet. Such an interface has to be carefully designed
because built-in operators assume that only records that have been
emitted previously are retracted. However, they are planned for future
Flink versions.
As a workaround you could implement a custom rule that translates parts
of your plan into a custom DataStream operator. This might require some
investigation how the translation is done internally because this is not
documented. I don't know if it would be worth the effort. You might take
a look at TableEnvironment.getConfig().setCalciteConfig() where you can
add additional rules. You can use the available rules in
org.apache.flink.table.plan.rules.FlinkRuleSets as a reference.
I hope this helps.
Regards,
Timo
Am 1/10/18 um 1:04 AM schrieb Yan Zhou [FDS Science]:
Hi,
There are APIs to convert a dynamic table to retract stream. Is there
any way to construct a "retract" data stream and convert it into
table? I want to read the change log of relational database from
kafka, "apply" the changes within flink( by creating CRow
DataStream), register/create a table on the CRow DataStream. Is there
any way to do this?
Best
Yan
