Local Pipeline Engine


The local runner runs on the local Hop engine. This is the runtime configuration you’ll use when testing pipelines on your local machine while developing.


Option Description Default

Row set size

The row set buffer size.


Safe mode

Checks every row passed through your pipeline and ensure all layouts are identical. If a row does not have the same layout as the first row, an error is generated and reported.


Collect metrics

Collects metrics to monitor the performance of your pipeline.


Sort transforms

Performs a topological sort of the transforms in the pipeline before execution.


Log rows feedback

Enables log rows feedback, showing a log line every after processing multiple of 50.000 (default) rows.


Feedback size in rows

The number of rows to return as feedback.


Wait time buffer check (ms)

This indicates the polling frequency when there are no rows in the input buffer of a transform, a lower value will cause higher CPU load when the pipeline has many idle transforms.


Sample type while running in the GUI

Here you can specify which rows you want to see when you click on the little grid icons on the transform icons during a pipeline execution. You can choose: None: do not show, First : show the first rows, Last : show the last rows or Random: a random selection of rows (reservoir sampling)


Number of rows to sample in the GUI

The number of rows which will be collected


Make this pipeline transactional

If you enable this there will always be just one connection used per database. At the end of the pipeline there will be a commit or rollback (in case of error) on all named connections at the same time. Note that child pipelines or workflows are also automatically run as a transaction. Also be aware that while you can commit and rollback across multiple databases that this still means that you can have a successful commit on one database and a failure on another. This is not a two-phase-commit system.