Fixing Pezzo's ClickHouse Timestamp Parse Error With One Insert Setting

Timestamps in one format, a database expecting another.

Resposta curta

Pezzo's reporting service inserted ISO-8601 timestamps, with milliseconds and a Z, into ClickHouse DateTime columns. With ClickHouse's basic input format, those values fail to parse, and testing a prompt locally raised CANNOT_PARSE_INPUT_ASSERTION_FAILED. The fix sends the insert with date_time_input_format: "best_effort". It was merged as PR #357 and closed issue #320.

The problem

Issue #320, on Pezzo 0.8.0 with Docker Compose, showed the error when running any prompt test:

ClickHouseError: Cannot parse input: expected '"' before: '.307Z",...': (while reading the value of key timestamp)

The fix

         format: "JSONEachRow",
         table: "reports",
         values: [reportToSave],
+        clickhouse_settings: {
+          date_time_input_format: "best_effort",
+        },

Setting it per insert means the parse works regardless of the server's default.

By the numbers

• Repository: pezzolabs/pezzo, 3,279 stars (Nov 3, 2026), TypeScript, Apache-2.0
• Files changed: 1
• Lines: +3 / -0
• Commits: 1
• Opened and merged: Aug 21, 2026. Time to merge: 3 hours, 38 minutes
• Review: merged by a maintainer

Perguntas frequentes

Where can I read more?

See the pull request and the original issue.

O objetivo

Observability data is only useful if it lands. Telling the database how to read the timestamps it is sent keeps the reports flowing.