ClickHouse Nodes
MaestroHub provides native ClickHouse integration for analytical queries, DML/DDL execution, and bulk inserts. Communication uses ClickHouse's native TCP protocol, with native typed binding for Map(K, V) / Array(T) / DateTime64 columns, full TLS / mTLS, and LZ4 / ZSTD wire compression.
Configuration Quick Reference
| Field | What you choose | Details |
|---|---|---|
| Parameters | Connection, Function, Function Parameters, Timeout Override | Select the connection profile, function, configure function parameters with expression support, and optionally override timeout. |
| Settings | Description, Timeout (seconds), Retry on Timeout, Retry on Fail, On Error | Node description, maximum execution time, retry behavior on timeout or failure, and error handling strategy. All execution settings default to pipeline-level values. |
Node Types
ClickHouse connector provides three specialized node types for different operation patterns:
| Node | Purpose | Common Use Cases |
|---|---|---|
| Query | Execute SELECT queries and return structured rows | Aggregations, time-series rollups, top-K analytics, enrichment lookups |
| Execute | Execute DML/DDL statements, return rows affected | INSERT … SELECT materialisation, schema migrations, OPTIMIZE TABLE maintenance |
| Write | Load pipeline data into a table with auto schema detection or auto MergeTree creation | Bulk telemetry ingest, native Map/Array column binding, auto-create on the fly |
ClickHouse Query Node
ClickHouse Query Node
Execute SQL SELECT queries and return rows as structured data. Supports parameterized queries with ((param)) syntax and full ClickHouse SQL — aggregate combinators, window functions, ARRAY JOIN, LIMIT BY, and time-series helpers like toStartOfHour() / toStartOfFiveMinute().
Supported Function Types:
| Function Name | Purpose | Common Use Cases |
|---|---|---|
| Query | Run parameterized SELECT queries against ClickHouse | Hourly / daily rollups, top-K dashboards, enrichment joins with dictionaries, latest-value lookups via argMax() |
ClickHouse Execute Node
ClickHouse Execute Node
Execute DML/DDL statements — INSERT, INSERT … SELECT, ALTER, CREATE, OPTIMIZE, TRUNCATE, and others — and return affected-row counts where ClickHouse reports them. Use for ad-hoc writes, schema migrations, and table maintenance.
Supported Function Types:
| Function Name | Purpose | Common Use Cases |
|---|---|---|
| Execute | Run any DML/DDL statement against ClickHouse | Materialise rollups with INSERT INTO … SELECT, add columns with ALTER TABLE … ADD COLUMN, force background merges with OPTIMIZE TABLE … FINAL, fast purges with TRUNCATE TABLE |
ClickHouse Write Node
ClickHouse Write Node
Bulk-insert pipeline rows into a ClickHouse table using batched VALUES inserts. Supports two paths: writing to an existing table (auto-detected schema mapping) or auto-creating a MergeTree table with operator-supplied ORDER BY. Native Map(K, V) and Array(T) columns are bound directly without JSON round-tripping — a pipeline field of {"unit": "celsius"} lands as a queryable Map, not a string blob.
Supported Function Types:
| Function Name | Purpose | Common Use Cases |
|---|---|---|
| Write | Load structured pipeline data into a ClickHouse table | Stream MQTT / OPC UA / Modbus telemetry into a MergeTree, auto-create tables from pipeline rows, append to a Distributed table fronting a cluster |