InTouch Hub · Blue Isle Software

ClickHouse

Run SQL against ClickHouse over its native HTTP interface — query, export to a delimited file, import from one, and inspect databases and tables. No JDBC driver to install.

Provided free and as is, without warranty of any kind — including merchantability, fitness for a particular purpose, and the accuracy or completeness of any result. See the licence. You are responsible for checking what this produces before relying on it.

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ClickHouse Connector

Runs SQL against a ClickHouse cluster over its HTTP interface (8123, or 8443 with TLS).

No JDBC driver is bundled. ClickHouse's HTTP interface covers queries, inserts and format conversion, so the connector needs no vendor driver — which keeps the JAR at ~4 MB and keeps it clear of driver/classloader conflicts.

Credential

Standard credential fields carry the connection; two extra properties are type-specific.

Field Description
Server ClickHouse host name or address — required
Port Leave 0 for the default: 8123, or 8443 when SSL is enabled
Login ClickHouse user (defaults to default)
Secret Password (may be blank on an unsecured dev cluster)
database Default database for statements that don't name one (default default)
ssl Connect over HTTPS — required by ClickHouse Cloud (default false)

Test runs SELECT version(), so a green result means the credentials authenticate and the database is reachable — not merely that the port accepts connections.

Operations

1. execute — Run SQL

Property Type Default Description
statement string — Required. SQL statement
maxRows integer 0 Rows to publish (0 = up to 1000)
settings string — Extra ClickHouse settings as a JSON object

Published (queries): rows, columns, rowCount, rowsPublished, truncated

rows is a JSON array of objects keyed by column name, with values as strings (null stays null) — every task output is text.

rowCount is the true number of rows returned; rowsPublished is how many are in rows, and truncated says whether they differ. Publishing is capped at maxRows (or 1000) because outputs are held in memory and written to the activity log — use export for large result sets.

DDL and DML statements simply run.

2. export — Query results to file

Property Type Default Description
statement string — Required. SQL SELECT statement
outputFile string — Required. Output file path
delimiter string comma comma, tab, pipe, other
customDelimiter string — Required when delimiter is other
hasHeader boolean true Include column header
maxRows integer 0 Max rows (0 = all)
nullFormat string — String for null values

Published: rowCount, outputFile

Behavior: ClickHouse does the formatting and the response is streamed straight to disk, so the result never has to fit in memory and the quoting is the server's own — values containing the delimiter, quotes or line breaks are escaped correctly.

3. import — Load file into table

Property Type Default Description
inputFile string — Required. Input file path
table string — Required. Target table
database string credential default Target database
delimiter string comma Field delimiter
hasHeader boolean true File has a header row
nullFormat string — String that represents null

Published: rowCount, inputFile, database, table

Behavior: The file is sent as the body of an INSERT and parsed by ClickHouse. With a header row, columns are matched to the table by name (input_format_with_names_use_header), so the file's column order does not need to match the table's. Without a header, values are taken in the table's own column order.

rowCount is measured as the table's row count before and after the load. On a table receiving concurrent writes that figure is approximate.

4. list-databases

Published: databases (comma-separated), count

5. list-tables

Property Type Default Description
database string credential default Database to list

Published: database, tables (comma-separated), count

6. describe

Property Type Default Description
database string credential default Database
table string — Required. Table

Published: database, table, columns, columnCount

Delimiters

comma and tab map to ClickHouse's CSV and TSV formats (the WithNames variants when a header is used). pipe and other use CustomSeparated with the delimiter applied as a format setting; when other is chosen a custom delimiter is required.

Testing status

Built and loaded against InTouch; the credential and task schemas, tool registration and HTTP error reporting are verified. The operations have not yet been exercised against a live ClickHouse server — no instance was available. Treat execute, export and import as untested until run against a real cluster.

Publishes

The keys a later task may reference as {{taskName.key}}. Referencing anything not listed here resolves to nothing at run time.

operation

Which action the step performs. It is the field that decides what every other field MEANS, so it is required and there is no default — a step that omits it is not a query with a missing verb, it is a step with no verb at all.

Read the values this build accepts from the tool itself rather than from this page: describe(clickhouse) returns the exact list, reflected from the bean at runtime, and cannot drift from what the executor will accept.