Console

A short summary of each query, printed to standard error.

Use it when

• You are working locally and want to see what each query cost, now.
• You are checking that instrumentation works before wiring up anything else.

Set up

import polars_telemetry
from polars_telemetry.export.console import ConsoleExporter

polars_telemetry.install(exporter=ConsoleExporter())

What you get

A header with the totals, the call site, and the twelve most expensive nodes:

polars query nightly/revenue_by_region ok wall=20.5ms cpu=81.7ms parallelism=3.99x nodes=6 rows_out=4
  at reports.py:23 in revenue_by_region()
  GroupBy               81.1ms  in=   2,696,064  out=           4
  Sort                  0.29ms  in=           4  out=           4
  SimpleProjection      0.16ms  in=   2,696,064  out=   2,696,064
  MultiScan             0.12ms  in=           0  out=   2,696,064
  InMemorySink            17us  in=           4  out=           0
  SimpleProjection        16us  in=           4  out=           4

The header names the query by its label, or by the start of its id. A failed query shows FAILED and polars' message instead of ok.

Options

Option	Default	Effect
stream	standard error	Any text stream, such as sys.stdout or an open file

Your data

The label, node kinds, row counts and the call site's file name. No plan expressions, so no literals.

Cost

About 10–30 µs per query, plus whatever the stream costs to write to.

When it fails

A stream that raises, such as a closed file, is logged once, and after five errors the exporter is disabled for the rest of the process.