feat: return a can_assume_strict_equality for in-memory joins by jacek-prisma · Pull Request #5785 · prisma/prisma-engines

jacek-prisma · 2026-02-25T14:55:09Z

TML-1868

/prisma-branch fix/strict-equality-joins

Client PR: prisma/prisma#29251

Summary by CodeRabbit

New Features
- Joins now carry a flag to enable stricter equality assumptions when supported, improving cross-database join handling.
- Validation expressions include richer context for clearer error reporting.
Chores
- Connector implementations updated to advertise support for strict-equality joins where applicable, enabling optimized query generation.

coderabbitai · 2026-02-25T14:55:35Z

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Reviewing files that changed from the base of the PR and between c0f3e1d and f18a7bc.

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query-compiler/query-compiler/src/expression.rs

Walkthrough

Adds Connector::can_assume_strict_equality_in_joins with default false and overrides returning true for several built-in connectors. Carries a new boolean into Expression::Join, augments Expression::Validate with error_identifier and context, adds serde rename attributes, and threads the join flag through query translation.

Changes

Cohort / File(s)	Summary
Trait Definition `psl/psl-core/src/datamodel_connector.rs`	Adds `fn can_assume_strict_equality_in_joins(&self) -> bool` to `Connector` with default `false`.
Connector Implementations `psl/psl-core/src/builtin_connectors/cockroach_datamodel_connector.rs`, `psl/psl-core/src/builtin_connectors/mongodb.rs`, `psl/psl-core/src/builtin_connectors/mssql_datamodel_connector.rs`, `psl/psl-core/src/builtin_connectors/postgres_datamodel_connector.rs`, `psl/psl-core/src/builtin_connectors/sqlite_datamodel_connector.rs`	Implement `can_assume_strict_equality_in_joins` returning `true` for Cockroach, MongoDB, MSSQL, Postgres, and SQLite connectors.
Expression System `query-compiler/query-compiler/src/expression.rs`, `query-compiler/query-compiler/src/expression/format.rs`	`Expression::Join` gains `can_assume_strict_equality: bool`; `Expression::Validate` gains `error_identifier: &'static str` and `context: serde_json::Value`; `#[serde(rename_all = "camelCase")]` added to both variants; pattern matches updated to use `..` where needed.
Query Translation `query-compiler/query-compiler/src/translate/query/read.rs`	Evaluates nested queries' connectors for strict-equality support and sets `can_assume_strict_equality` when constructing `Expression::Join`.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The PR title accurately summarizes the main change: adding a can_assume_strict_equality capability for in-memory joins, which is the primary feature across all modified files.

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codspeed-hq · 2026-02-25T14:58:25Z

Merging this PR will not alter performance

✅ 11 untouched benchmarks
⏩ 11 skipped benchmarks¹

_{Comparing fix/strict-equality-joins (f18a7bc) with main (c6be8e6)}

11 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

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Actionable comments posted: 2

ℹ️ Review info

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between c6be8e6 and 7ba99aa.

📒 Files selected for processing (5)

psl/psl-core/src/builtin_connectors/mysql_datamodel_connector.rs
psl/psl-core/src/datamodel_connector.rs
query-compiler/query-compiler/src/expression.rs
query-compiler/query-compiler/src/expression/format.rs
query-compiler/query-compiler/src/translate/query/read.rs

psl/psl-core/src/datamodel_connector.rs

query-compiler/query-compiler/src/translate/query/read.rs

github-actions · 2026-02-25T15:05:42Z

Wasm Query Compiler File Size

Engine	This PR	Base branch	Diff
Postgres	3.505MiB	3.505MiB	162.000B
Postgres (gzip)	1.142MiB	1.142MiB	22.000B
Postgres (size-optimized)	1.766MiB	1.766MiB	159.000B
Postgres (size-optimized, gzip)	694.997KiB	694.771KiB	231.000B
Mysql	3.458MiB	3.457MiB	170.000B
Mysql (gzip)	1.127MiB	1.127MiB	53.000B
Mysql (size-optimized)	1.736MiB	1.736MiB	159.000B
Mysql (size-optimized, gzip)	684.226KiB	683.919KiB	314.000B
Sqlite	3.376MiB	3.376MiB	162.000B
Sqlite (gzip)	1.098MiB	1.099MiB	-125.000B
Sqlite (size-optimized)	1.692MiB	1.692MiB	151.000B
Sqlite (size-optimized, gzip)	667.290KiB	667.310KiB	-21.000B
SQL Server	3.598MiB	3.598MiB	170.000B
SQL Server (gzip)	1.162MiB	1.162MiB	192.000B
SQL Server (size-optimized)	1.766MiB	1.766MiB	151.000B
SQL Server (size-optimized, gzip)	698.656KiB	698.218KiB	448.000B
CockroachDB	3.555MiB	3.555MiB	174.000B
CockroachDB (gzip)	1.160MiB	1.160MiB	36.000B
CockroachDB (size-optimized)	1.791MiB	1.791MiB	155.000B
CockroachDB (size-optimized, gzip)	705.226KiB	704.995KiB	237.000B

[TML-1868](https://linear.app/prisma-company/issue/TML-1868/fix-mysql-bigint-relation-issue) Adds support for a new `canAssumeStrictEquality` flag used for in-memory joins. When it's set to false, we infer the type of the key present on the parent rows and inject casts for children rows. Fixes some MySQL edge cases. Fixes #29122 Engine PR: prisma/prisma-engines#5785  ## Summary by CodeRabbit * **Bug Fixes** * Improved join key matching with optional per-field value mapping/type casting and a new flag to control strict-equality assumptions. * Standardized validation error identifiers to camelCase for more consistent error reporting. * **Tests** * Added MySQL-only functional tests for view relations with large BigInt keys. * **Chores** * Updated internal engine/tooling version references.  --------- Co-authored-by: Prismo <prismabots@gmail.com>

feat: return a can_assume_strict_equality for in-memory joins

7ba99aa

jacek-prisma mentioned this pull request Feb 25, 2026

fix: support joins that do not require strict equality prisma/prisma#29251

Merged

coderabbitai bot reviewed Feb 25, 2026

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psl/psl-core/src/datamodel_connector.rs Show resolved Hide resolved

query-compiler/query-compiler/src/translate/query/read.rs Show resolved Hide resolved

jacek-prisma added 3 commits February 25, 2026 15:30

chore: flip the default and impls

c0f3e1d

chore: rebuild

a4bf4e1

fix: camel case snake case names

f18a7bc

aqrln approved these changes Feb 27, 2026

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jacek-prisma merged commit 94a226b into main Feb 27, 2026
98 of 99 checks passed

jacek-prisma deleted the fix/strict-equality-joins branch February 27, 2026 08:20

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feat: return a can_assume_strict_equality for in-memory joins#5785

feat: return a can_assume_strict_equality for in-memory joins#5785
jacek-prisma merged 4 commits intomainfrom
fix/strict-equality-joins

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Summary by CodeRabbit

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Walkthrough

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Merging this PR will not alter performance

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Wasm Query Compiler File Size

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jacek-prisma commented Feb 25, 2026 •

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