fix(migrations): Send HTTP progress during long ON CLUSTER DDL - #8413
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Quiet DROP TABLE ... ON CLUSTER SYNC can sit on a hot-table lock with no HTTP bytes, so http_send_timeout / idle IncompleteRead the body. Match REPLACE: send_progress_in_http_headers every 15s. Refs SNUBA-C3Y
phacops
marked this pull request as ready for review
August 28, 2026 19:02
phacops
enabled auto-merge (squash)
August 28, 2026 19:12
pbhandari
approved these changes
Aug 28, 2026
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MIGRATE DDL can sit on a lock (DROP of an MV on a hot table) without writing HTTP bytes. ClickHouse then hits
http_send_timeout/ idle and the client seesIncompleteReadeven though the statement is still running.The MIGRATE profile now sends progress headers every 15s, same as REPLACE. SYNC and
distributed_ddl_task_timeoutare unchanged; this only keeps the HTTP stream alive until ClickHouse actually finishes.Refs SNUBA-C3Y