Félix Malfait
2a21eb46c0
## Problem Record table views that show a to-many relation column (e.g. Workflows with a "Runs" column) get slow and janky to scroll when some records have many related records. Two root causes, found by profiling the page live: 1. **Backend over-fetch + unfairness.** Nested one-to-many relations were loaded with a single flat limit of `QUERY_MAX_RECORDS_FROM_RELATION * parentCount` shared across *all* parents in the page (`WHERE parentColumn IN (ids) LIMIT 60*N`, no per-parent cap). A single hot parent can consume the entire budget — returning thousands of rows for one cell, and potentially starving sibling parents of records they actually have. The `limit * parentCount` shape shows the original intent *was* a per-parent budget; it was just implemented as a global limit. 2. **Frontend DOM explosion.** `ExpandableList` mounts the *entire* child array inline (clipped with `overflow: hidden`) when unfocused, and mounts all children for measurement when focused. A cell with 2,000+ relation chips mounts ~14k DOM nodes — one observed page reached ~55k nodes for 43 rows, producing 100–300 ms main-thread long tasks on every scroll. ## Fix - **Backend:** load one-to-many relations with a true **per-parent** cap via a `LATERAL` join — each parent runs its own indexed, `LIMIT`-ed scan that stops after the per-parent budget. This is `O(perParentLimit × parentCount)` and never reads or sorts a parent's full relation set. The per-parent query is built through the workspace query builder (so it stays schema-qualified and keeps the soft-delete predicate) and wrapped as a `FROM` subquery; read/row-level permissions are enforced when records are hydrated by id, as elsewhere in the relation loader. Many-to-one is unchanged. - **Frontend:** add an opt-in `maxInlineCount` to `ExpandableList` so to-many relation cells mount only a small inline preview; the expand dropdown still renders the full fetched set. Fully backward compatible (no cap → identical behavior). ## Why LATERAL over a window function A windowed `ROW_NUMBER() OVER (PARTITION BY parent) <= limit` is correct and fair too, but a window function **cannot stop early within a partition** — it must read every matching row (and sort it). Measured on skewed data (one parent with ~4k children, on the existing single-column join index, PG16): | Approach | Time | Buffers | Rows read from the hot partition | |---|---|---|---| | Pre-PR (`LIMIT 60×N`) | 1.6 ms | 91 | ~180 total, early-stops, but **unfair** (starves siblings) | | Window (`ROW_NUMBER`) | 3.7 ms | 128 | **all ~4k + sort** | | **LATERAL (`per-parent LIMIT`)** | **0.5 ms** | **57** | **~60, index early-stop** | LATERAL matches the pre-PR read cost while being fair, needs no new index, and scales independently of how large any single relation is. ## Verification - Backend integration test (`nested-relation-per-parent-limit`): a parent with 65 children is capped at 60 while a sibling with 3 keeps all 3 — passes. - `EXPLAIN ANALYZE` on the generated SQL: Index Scan with the `LIMIT` pushed into the per-parent lateral (early-stop). - Frontend unit test for the `ExpandableList` cap. - Manual check on a table cell with 40 related records: exactly 10 chips mount inline (down from 40), no console errors, chips still clickable and the overflow count reflects the true total.
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import { defineObject, FieldType } from 'twenty-sdk/define';
export default defineObject({
nameSingular: 'deal',
namePlural: 'deals',
labelSingular: 'Deal',
labelPlural: 'Deals',
fields: [
{ name: 'name', label: 'Name', type: FieldType.TEXT },
{ name: 'amount', label: 'Amount', type: FieldType.CURRENCY },
{ name: 'closeDate', label: 'Close Date', type: FieldType.DATE_TIME },
],
});
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