Knowledge Base

ClickHouse provides introspection tools like `system.stack_trace` for inspecting what code is currently running on each server thread, helping with debugging and performance monitoring.

Learn various methods to export data from ClickHouse, including `INTO OUTFILE`, the File table engine, and command-line redirection.

Learn the basics of using the S3 table engine in ClickHouse to ingest and query Parquet files from an S3 bucket, including setup, access permissions, and data import examples.

Learn how to use ClickHouse's `clickhouse-local` tool to easily convert Parquet files to CSV or JSON formats.

Learn how to export PostgreSQL data to Parquet, CSV, or JSON formats using `clickhouse-local` with various examples.

Learn how to use the `clickhouse-local` tool to export MySQL data into formats like Parquet, CSV, or JSON quickly and efficiently.

Learn how to fix timeout errors when using `remote` or `remoteSecure` table functions in ClickHouse by adjusting the connection timeout settings.

Learn how to address the "Too many parts" error in ClickHouse by optimizing insert rates, configuring MergeTree settings, and managing partitions effectively.

There are multiple JSON variations among them, but the most commonly used for data ingestion is JSONEachRow. It expects one JSON object per row, each object separated by a newline.

A collection of handy queries for troubleshooting ClickHouse, including monitoring table sizes, long-running queries, and errors.