Automating reports in ClickHouse means pre-computing and optionally exporting recurring query results on a schedule using Materialized Views, cron, or the built-in task scheduler.
Automated reports avoid heavy ad-hoc queries, guarantee consistent metrics, and let BI tools fetch pre-computed data quickly.
Use one of three options: (1) Materialized Views that auto-refresh on INSERT, (2) the experimental CREATE TASK scheduler (v23.7+), or (3) an external cron job that calls clickhouse-client.
Ensure UTC server time, MergeTree tables with proper PARTITION BY clauses, and enough disk for roll-ups.
Create a summary table, then attach a Materialized View that aggregates Orders into it.The view populates automatically as new orders arrive.
Yes. A CREATE TASK or cron can run SELECT ... INTO OUTFILE or use clickhouse-curl to stream results to S3.
Place each summary in its own Materialized View, then add a second view that unions or joins them.Alternatively, run dependent CREATE TASK jobs with AFTER dependencies.
Partition summary tables by report date, keep rows narrow, index by business keys, and set TTL to purge old data automatically.
Query system.tables for lagging MV rows, check system.tasks for failed jobs, and emit logs to Grafana.
1) Create table 2) Create MV 3) Optional CREATE TASK to export yesterday’s slice to S3.
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Yes. Insert historical rows into the source table; the MV replays automatically. For large volumes, INSERT in date batches to avoid merges overload.
Each task keeps last_status in system.tasks. Use retry_interval and max_retries settings to control automatic retries.
ALTER TASK task_name DISABLE pauses execution without dropping the job. Re-enable with ENABLE.