Upgrading to SigNoz 0.57.0 broke log-based value widgets (report 0)

TL;DR

Removing all where conditions makes the old widget work; re-adding them fixes it, which rules out the query itself.

Steps

1. After upgrading SigNoz from 0.56.0 to 0.57.0, existing log-based value widgets on dashboards report 0, while recreating the identical widget shows correct numbers. Removing all where conditions makes the old widget work; re-adding them fixes it, which rules out the query itself.
2. Root cause: stale metadata in ClickHouse. If your team ever switched from log attributes to resource attributes (e.g. for service.name), the old tag keys stay in distributed_logs_attribute_keys / distributed_tag_attributes, and the old widgets keep querying attributes_string while new widgets resolve to resource attributes. Fix (confirmed by the reporter): exec into ClickHouse and run TRUNCATE TABLE signoz_logs.logs_attribute_keys ON CLUSTER cluster and TRUNCATE TABLE signoz_logs.tag_attributes ON CLUSTER cluster. Note truncating the distributed_ variants does not delete the data. Then re-select the where conditions pointing at Type: Resource.

When to use

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When not to use

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Versions

Versions mentioned in the source: 0.56.0, 0.57.0. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Edge cases

• Note truncating the distributed_ variants does not delete the data.

Question asked in the thread: After upgrading SigNoz from 0.56.0 to 0.57.0, existing log-based value widgets on dashboards report 0, while recreating the identical widget shows correct numbers. Removing all where conditions makes the old widget work; re-adding them fixes it, which rules out the query itself.

Verified answer: Root cause: stale metadata in ClickHouse. If your team ever switched from log attributes to resource attributes (e.g. for service.name), the old tag keys stay in distributed_logs_attribute_keys / distributed_tag_attributes, and the old widgets keep querying attributes_string while new widgets resolve to resource attributes. Fix (confirmed by the reporter): exec into ClickHouse and run TRUNCATE TABLE signoz_logs.logs_attribute_keys ON CLUSTER cluster and TRUNCATE TABLE signoz_logs.tag_attributes ON CLUSTER cluster. Note truncating the distributed_ variants does not delete the data. Then re-select the where conditions pointing at Type: Resource.

Source: https://github.com/SigNoz/signoz/issues/6304

Thread: https://vectle.com/threads/thr_CuuXxQ4peW8k3mpAV2YFNw