Matt Aitken
2cac63f13a
## Problem Several display/grouping issues in the **Errors** feature, all rooted in how the ClickHouse error materialized views (`errors_mv_v1`, `error_occurrences_mv_v1`) read the stored error JSON produced by `parseError`: 1. **Messageless errors show "Unknown error".** An empty message falls straight through `coalesce(nullIf(message,''), 'Unknown error')` to the literal, even though the error's class `name` is available (e.g. an Effect tagged error `ListMessagesError` with no message). 2. **Unrelated errors collapse into one group.** `calculateErrorFingerprint` keys on `type : message : stack`, where `type` is always the union tag (`BUILT_IN_ERROR`, …), `message` is empty, and the stack isn't read — so every messageless built-in error (and every string/custom error) hashes to the same constant input → one fingerprint. 3. **error_type shows the internal tag.** `coalesce(type, name, …)` always resolves to `type` (always present), so the column shows `BUILT_IN_ERROR` instead of the real class name. 4. **Stack traces never populate.** The MVs read `error.data.stack`, but the serializer stores the trace under `stackTrace` — so the column is always empty. ## Fix All display changes are `ALTER TABLE … MODIFY QUERY` on the two views (migration `035`); the fingerprint change is in the webapp. - **Fingerprint** (`errorFingerprinting.ts`): fall back **message → name → raw**. Messageless errors now group by class name (or raw value for non-Error throws); message-bearing errors are **unchanged** (short-circuits at `message`), so existing groups don't split — only currently-messageless errors get their own group going forward. - **error_message**: same `message → name → raw` fallback before `'Unknown error'`. - **error_type**: coalesce `name → code → 'Error'` (drops the reliance on the union tag). Built-in → class name, internal → `code`, string/custom → `Error`. - **stack trace**: read `error.data.stackTrace`. Bounded as before (serializer caps 50 frames / 1024 chars per line; MV clips to 2000 chars). ## Migration notes - `MODIFY QUERY` swaps the view query in place (no drop/recreate gap); Down restores the previous query. - **Existing rows are left unchanged** — changes apply only to rows inserted after the migration. No backfill. ## Tests `errorFingerprinting.test.ts` — 57 pass, incl. new cases for messageless class names, string/custom raw values, and stability of message-bearing fingerprints. Fixes the display-derivation half of TRI-11938 (error_type + stack trace); relates to TRI-9254 and TRI-9250.
ClickHouse Table Naming Conventions
The following document is heavily inspired by the Unkey ClickHouse naming conventions.
This document outlines the naming conventions for tables and materialized views in our ClickHouse setup. Adhering to these conventions ensures consistency, clarity, and ease of management across our data infrastructure.
General Rules
- Use lowercase letters and separate words with underscores.
- Avoid ClickHouse reserved words and special characters in names.
- Be descriptive but concise.
Table Naming Convention
Format: [prefix]_[domain]_[description]_[version]
Prefixes
raw_: Input data tablestmp_{yourname}_: Temporary tables for experiments, add your name, so it's easy to identify ownership.
Versioning
- Version numbers:
_v1,_v2, etc.
Aggregation Suffixes
For aggregated or summary tables, use suffixes like:
_per_day_per_month_summary
Materialized View Naming Convention
Format: [description]_[aggregation]_mv_[version]
- Always suffix with
mv_[version] - Include a description of the view's purpose
- Add aggregation level if applicable
Examples
-
Raw Data Table:
raw_sales_transactions_v1 -
Materialized View:
active_users_per_day_mv_v2 -
Temporary Table:
tmp_eric_user_analysis_v1 -
Aggregated Table:
sales_summary_per_hour_mv_v1
Consistency Across Related Objects
Maintain consistent naming across related tables, views, and other objects:
raw_user_activity_v1user_activity_per_day_v1user_activity_per_day_mv_v1
By following these conventions, we ensure a clear, consistent, and scalable naming structure for our ClickHouse setup.