JDBC read DB causeOutOfMemoryError: Java heap space

2022-01-18 Thread Qihua Yang
Hi, I have a flink cluster(50 hosts, each host runs a task manager). I am using Flink JDBC to consume data from a database. The db table is pretty large, around 18734 rows. I configured the JDBC number of partitions to 50. fetchSize is 20. Flink application has 50 task managers. Anyone know wh

Re: JDBC read DB causeOutOfMemoryError: Java heap space

2022-01-18 Thread Qihua Yang
Here is the errors Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "server-timer" Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "I/O dispatcher 16" Exception: java.lang.OutOfMemoryError thrown from the UncaughtExcep

Re: JDBC read DB causeOutOfMemoryError: Java heap space

2022-01-18 Thread Caizhi Weng
Hi! This is not the desired behavior. As you have set fetchSize to 20 there will be only 20 records in each parallelism of the source. How large is your heap size? Does your job have any other operations which consume a lot of heap memory? Qihua Yang 于2022年1月19日周三 15:27写道: > Here is the errors

Re: JDBC read DB causeOutOfMemoryError: Java heap space

2022-01-18 Thread Qihua Yang
Hi Caizhi, Thank you for your reply. The heap size is 512m. Fetching from the DB table is the only costly operation. After fetching from DB, I simply ingested a kafka topic. That should not be the bottleneck. Here is the jdbc configuration. Is that correct config? val query = String.format("SELEC

Re: JDBC read DB causeOutOfMemoryError: Java heap space

2022-01-19 Thread Qihua Yang
Should I change the query? something like below to add a limit? If no limit, does that mean flink will read whole huge table to memory and fetch and return 20 records each time? val query = String.format("SELECT * FROM %s limit 1000", tableName) On Tue, Jan 18, 2022 at 11:56 PM Qihua Yang wrote

Re: JDBC read DB causeOutOfMemoryError: Java heap space

2022-01-24 Thread Caizhi Weng
Hi! Sorry for the late reply. Which Flink version are you using? For current Flink master there is no JdbcTableSource. Qihua Yang 于2022年1月19日周三 16:00写道: > Should I change the query? something like below to add a limit? If no > limit, does that mean flink will read whole huge table to memory and