bench: cover dictionary hash cache workloads by Rich-T-kid · Pull Request #27246 · apache/datafusion

Rich-T-kid · 2026-11-08T18:18:44Z

Which issue does this PR close?

Follow-up to #26826.

Rationale for this change

Adds the benchmark cases requested in this review thread. They are kept separate so the runtime change in #26826 stays focused.

What changes are included in this PR?

Extends dictionary_group_values with cases that cover:

alternating 100K-value dictionaries between batches, with and without an additional Int32 group key
one large dictionary values array shared by every batch
a fresh 20-value dictionary per batch, matching dictionaries produced by a projection cast

The existing cases are unchanged. There are no runtime code changes.

What is the testing strategy for this PR?

Each new benchmark runs in Criterion test mode.

Are there any user-facing changes?

No.

Rich-T-kid · 2026-11-08T19:19:30Z

cc @jayzhan211 🙇

adriangbot · 2026-11-12T15:39:33Z

Benchmark for this request failed before finishing (Kubernetes reason: BackoffLimitExceeded).

Benchmarks requested: tpch

Runner log (last 40 lines)

2026-11-12T15:38:47.395789Z  INFO runner starting benchmark runner bench_type=Datafusion, pr_url=https://github.com/apache/datafusion/pull/27246, benchmarks=tpch
2026-11-12T15:38:47.470940Z  INFO benchmark_controller::runner::bench_datafusion === Cloning PR branch ===
2026-11-12T15:38:47.470961Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["clone", "--depth=200", "https://github.com/apache/datafusion.git", "/workspace/datafusion-branch"], cwd="/"
2026-11-12T15:38:57.481351Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin", "refs/pull/27246/head:rich-T-kid/dictionary-group-values-cache-benchmarks", "main"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:02.482828Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["checkout", "rich-T-kid/dictionary-group-values-cache-benchmarks"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:07.485159Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["merge-base", "HEAD", "origin/main"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:12.487356Z  INFO benchmark_controller::runner::bench_datafusion === Checking out custom changed ref === changed_ref=e19b54c40917e3fad70a2743fc79881a0be43da3
2026-11-12T15:39:12.487371Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin", "refs/pull/27246/head"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:17.488875Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:22.491429Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["-c", "advice.detachedHead=false", "checkout", "e19b54c40917e3fad70a2743fc79881a0be43da3"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:27.492780Z ERROR runner benchmark failed error=git checkout: git -c advice.detachedHead=false checkout e19b54c40917e3fad70a2743fc79881a0be43da3 exited with code 128
stdout:

stderr:
fatal: reference is not a tree: e19b54c40917e3fad70a2743fc79881a0be43da3

Kubernetes message

Job has reached the specified backoff limit

File an issue against this benchmark runner

adriangbot · 2026-11-12T15:39:34Z

Benchmark for this request failed before finishing (Kubernetes reason: BackoffLimitExceeded).

Benchmarks requested: tpcds

Runner log (last 40 lines)

2026-11-12T15:38:51.918618Z  INFO runner starting benchmark runner bench_type=Datafusion, pr_url=https://github.com/apache/datafusion/pull/27246, benchmarks=tpcds
2026-11-12T15:38:51.980170Z  INFO benchmark_controller::runner::bench_datafusion === Cloning PR branch ===
2026-11-12T15:38:51.980191Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["clone", "--depth=200", "https://github.com/apache/datafusion.git", "/workspace/datafusion-branch"], cwd="/"
2026-11-12T15:38:56.990270Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin", "refs/pull/27246/head:rich-T-kid/dictionary-group-values-cache-benchmarks", "main"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:01.992747Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["checkout", "rich-T-kid/dictionary-group-values-cache-benchmarks"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:06.994748Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["merge-base", "HEAD", "origin/main"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:11.999001Z  INFO benchmark_controller::runner::bench_datafusion === Checking out custom changed ref === changed_ref=e19b54c40917e3fad70a2743fc79881a0be43da3
2026-11-12T15:39:11.999017Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin", "refs/pull/27246/head"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:17.001573Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:22.003250Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["-c", "advice.detachedHead=false", "checkout", "e19b54c40917e3fad70a2743fc79881a0be43da3"], cwd="/workspace/datafusion-branch"
2026-11-12T15:39:27.005550Z ERROR runner benchmark failed error=git checkout: git -c advice.detachedHead=false checkout e19b54c40917e3fad70a2743fc79881a0be43da3 exited with code 128
stdout:

stderr:
fatal: reference is not a tree: e19b54c40917e3fad70a2743fc79881a0be43da3

Kubernetes message

Job has reached the specified backoff limit

File an issue against this benchmark runner

adriangbot · 2026-11-12T15:40:35Z

Benchmark for this request failed before finishing (Kubernetes reason: BackoffLimitExceeded).

Benchmarks requested: clickbench_partitioned

Runner log (last 40 lines)

2026-11-12T15:39:50.816275Z  INFO runner starting benchmark runner bench_type=Datafusion, pr_url=https://github.com/apache/datafusion/pull/27246, benchmarks=clickbench_partitioned
2026-11-12T15:39:50.867521Z  INFO benchmark_controller::runner::bench_datafusion === Cloning PR branch ===
2026-11-12T15:39:50.867542Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["clone", "--depth=200", "https://github.com/apache/datafusion.git", "/workspace/datafusion-branch"], cwd="/"
2026-11-12T15:40:00.873138Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin", "refs/pull/27246/head:rich-T-kid/dictionary-group-values-cache-benchmarks", "main"], cwd="/workspace/datafusion-branch"
2026-11-12T15:40:05.876115Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["checkout", "rich-T-kid/dictionary-group-values-cache-benchmarks"], cwd="/workspace/datafusion-branch"
2026-11-12T15:40:10.877490Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["merge-base", "HEAD", "origin/main"], cwd="/workspace/datafusion-branch"
2026-11-12T15:40:15.879710Z  INFO benchmark_controller::runner::bench_datafusion === Checking out custom changed ref === changed_ref=e19b54c40917e3fad70a2743fc79881a0be43da3
2026-11-12T15:40:15.879725Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin", "refs/pull/27246/head"], cwd="/workspace/datafusion-branch"
2026-11-12T15:40:20.881268Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["fetch", "origin"], cwd="/workspace/datafusion-branch"
2026-11-12T15:40:25.883783Z  INFO benchmark_controller::runner::shell running command cmd=git, args=["-c", "advice.detachedHead=false", "checkout", "e19b54c40917e3fad70a2743fc79881a0be43da3"], cwd="/workspace/datafusion-branch"
2026-11-12T15:40:30.886110Z ERROR runner benchmark failed error=git checkout: git -c advice.detachedHead=false checkout e19b54c40917e3fad70a2743fc79881a0be43da3 exited with code 128
stdout:

stderr:
fatal: reference is not a tree: e19b54c40917e3fad70a2743fc79881a0be43da3

Kubernetes message

Job has reached the specified backoff limit

File an issue against this benchmark runner

…6826) ## Which issue does this PR close? Closes apache#26812. ## Rationale for this change Dictionary batches often share one values array while only their keys change. Partial aggregation was rehashing the same dictionary values for every batch. ## What changes are included in this PR? The non-streaming group table now caches dictionary value hashes while the values `Arc` is unchanged. A single dictionary group key can also map known keys directly to group indices. ```text Dictionary batch | v single dictionary column + complete cached mapping? | yes | no v v keys -> cached group IDs per-column hashing | | eligible dictionary fallback | | cached value hashes hash column | | scatter through keys -----+ | v hash/equality group lookup ``` New keys, changed or oversized dictionaries, and partial emission use the normal fallback. Multi-column hashing keeps the same semantics as `create_hashes`. The benchmark fixtures are split into apache#27246. ## What is the testing strategy for this PR? Unit tests cover cached and uncached hash consistency, unseen keys, changed dictionaries, null groups, partial emission, and forced collisions. Hosted cases from apache#27246 show [alternating dictionary-only](apache#26826 (comment)) 1.30× faster; [alternating dictionary + Int32](apache#26826 (comment)) and [fresh dictionaries](apache#26826 (comment)) flat; and [shared dictionary + Int32](apache#26826 (comment)) 1.14× faster at 32K values and 1.28× at 100K. Exact-head hosted suites with RLE dictionary reads enabled on both sides: - [TPC-H](apache#27249 (comment)): 796.01 → 799.79 ms (0.5% higher). - [TPC-DS](apache#27249 (comment)): 9.02 → 8.88 s (1.6% lower). - [ClickBench](apache#27249 (comment)): 38.26 → 38.16 s (0.3% lower). ## Are there any user-facing changes? No. --------- Co-authored-by: Jay Zhan <[email protected]>

github-actions Bot added the physical-plan Changes to the physical-plan crate label Nov 8, 2026

Rich-T-kid mentioned this pull request Nov 8, 2026

perf(aggregate): reuse dictionary hashes and group mappings #26826

Merged

bench: cover dictionary hash cache workloads

4c510c0

Rich-T-kid force-pushed the rich-T-kid/dictionary-group-values-cache-benchmarks branch from 289a4b0 to 4c510c0 Compare November 8, 2026 18:30

Rich-T-kid marked this pull request as ready for review November 8, 2026 19:19

Rich-T-kid marked this pull request as draft November 12, 2026 15:54

Rich-T-kid closed this Nov 14, 2026

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bench: cover dictionary hash cache workloads - #27246

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Rich-T-kid commented Nov 8, 2026 •

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