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Posted to issues@flink.apache.org by "Leonard Xu (Jira)" <ji...@apache.org> on 2025/03/05 14:32:00 UTC
[jira] [Updated] (FLINK-37120) MySqlSnapshotSplitAssigner assign the ending chunk early to avoid TaskManager OOM
[ https://issues.apache.org/jira/browse/FLINK-37120?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Leonard Xu updated FLINK-37120:
-------------------------------
Fix Version/s: cdc-3.4.0
> MySqlSnapshotSplitAssigner assign the ending chunk early to avoid TaskManager OOM
> ---------------------------------------------------------------------------------
>
> Key: FLINK-37120
> URL: https://issues.apache.org/jira/browse/FLINK-37120
> Project: Flink
> Issue Type: Improvement
> Components: Flink CDC
> Affects Versions: cdc-3.2.1
> Reporter: JunboWang
> Assignee: JunboWang
> Priority: Minor
> Labels: pull-request-available
> Fix For: cdc-3.4.0
>
>
> When synchronizing a large table, the ending chunk is always executed last, and splitEnd is null. This causing the task to scan too much data and eventually TaskManager OOM.
>
> Related log:
> {code:java}
> // code placeholder
> 2025-01-13T20:52:01.926+0800: 136.022: [Full GC (Allocation Failure) 2025-01-13T20:52:01.926+0800: 136.022: [Tenured: 1713535K->1713535K(1713536K), 3.6111578 secs] 2484607K->2482139K(2484608K), [Metaspace: 89121K->89121K(1130496K)], 3.6113026 secs] [Times: user=3.20 sys=0.40, real=3.61 secs]
> 2025-01-13T20:52:05.555+0800: 139.651: [Full GC (Allocation Failure) 2025-01-13T20:52:05.555+0800: 139.651: [Tenured: 1713535K->1713535K(1713536K), 3.9733441 secs] 2484607K->2482375K(2484608K), [Metaspace: 89133K->89133K(1130496K)], 3.9734511 secs] [Times: user=3.52 sys=0.45, real=3.98 secs]
> 2025-01-13T20:52:09.548+0800: 143.644: [Full GC (Allocation Failure) 2025-01-13T20:52:09.548+0800: 143.644: [Tenured: 1713535K->1713535K(1713536K), 3.3805432 secs] 2484607K->2482897K(2484608K), [Metaspace: 89134K->89134K(1130496K)], 3.3806496 secs] [Times: user=3.36 sys=0.02, real=3.38 secs] {code}
> {code:java}
> // code placeholder
> 2025-01-13 20:49:54,563 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.context.StatefulTaskContext [] - Starting offset is initialized to {ts_sec=0, file=, pos=0, kind=EARLIEST, row=0, event=0}
> 2025-01-13 20:49:54,631 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - Snapshot step 1 - Determining low watermark {ts_sec=0, file=mysql-bin.xxxxx, pos=xxxxx, kind=SPECIFIC, gtids=xxxxxxxxx, row=0, event=0} for split MySqlSnapshotSplit{tableId=xxxxdb.xxxxx_test_table, splitId='xxxxdb.xxxxx_test_table:159959', splitKeyType=[`id` BIGINT NOT NULL], splitStart=[1333738235], splitEnd=null, highWatermark=null}
> 2025-01-13 20:49:54,636 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - Snapshot step 2 - Snapshotting data
> 2025-01-13 20:49:54,636 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - Exporting data from split 'xxxxdb.xxxxx_test_table:159959' of table xxxxdb.xxxxx_test_table
> 2025-01-13 20:49:54,637 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - For split 'xxxxdb.xxxxx_test_table:159959' of table xxxxdb.xxxxx_test_table using select statement: 'SELECT * FROM `xxxxdb`.`xxxxx_test_table` WHERE `id` >= ?'
> 2025-01-13 20:50:17,482 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - Exported 167463 records for split 'xxxxdb.xxxxx_test_table:159959' after 00:00:22.846
> 2025-01-13 20:50:31,627 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - Exported 409419 records for split 'xxxxdb.xxxxx_test_table:159959' after 00:00:36.991
> 2025-01-13 20:50:41,805 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - Exported 510663 records for split 'xxxxdb.xxxxx_test_table:159959' after 00:00:47.169
> 2025-01-13 20:50:55,184 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - Exported 588220 records for split 'xxxxdb.xxxxx_test_table:159959' after 00:01:00.548
> 2025-01-13 20:51:05,580 INFO org.apache.flink.cdc.connectors.mysql.debezium.task.MySqlSnapshotSplitReadTask [] - Exported 615374 records for split 'xxxxdb.xxxxx_test_table:159959' after 00:01:10.944 {code}
>
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