Perf: load default Utf8View for CSV datatype

[zhuqi-lucas]

Which issue does this PR close?

• Closes#16241

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[alamb]

🤖 ./gh_compare_branch.shBenchmark Script Running
Linux aal-dev 6.11.0-1013-gcp #13~24.04.1-Ubuntu SMP Wed Apr 2 16:34:16 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
Comparing default_utf8_for_unkown_type (7586ca2) to 5b08b84diff
Benchmarks: h2o_small_window
Results will be posted here when complete

[alamb]

🤖: Benchmark completed

Details

Comparing HEAD and default_utf8_for_unkown_type
--------------------
Benchmark h2o_window.json
--------------------
┏━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┓
┃ Query ┃ HEAD ┃ default_utf8_for_unkown_type ┃ Change ┃
┡━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━┩
│ QQuery 1 │ 1907.12ms │ 1874.72ms │ no change │
│ QQuery 2 │ 3435.06ms │ 3435.28ms │ no change │
│ QQuery 3 │ 3836.65ms │ 4366.66ms │ 1.14x slower │
│ QQuery 4 │ 1008.06ms │ 959.61ms │ no change │
│ QQuery 5 │ 2238.31ms │ 2291.12ms │ no change │
│ QQuery 6 │ 2998.08ms │ 2978.58ms │ no change │
│ QQuery 7 │ 2948.78ms │ 2920.08ms │ no change │
│ QQuery 8 │ 11870.28ms │ 12098.03ms │ no change │
│ QQuery 9 │ 866.09ms │ 852.79ms │ no change │
│ QQuery 10 │ 938.85ms │ 940.99ms │ no change │
│ QQuery 11 │ 910.25ms │ 894.20ms │ no change │
│ QQuery 12 │ 1769.99ms │ 1741.19ms │ no change │
└──────────────┴────────────┴──────────────────────────────┴──────────────┘
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┓
┃ Benchmark Summary ┃ ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━┩
│ Total Time (HEAD) │ 34727.52ms │
│ Total Time (default_utf8_for_unkown_type) │ 35353.24ms │
│ Average Time (HEAD) │ 2893.96ms │
│ Average Time (default_utf8_for_unkown_type) │ 2946.10ms │
│ Queries Faster │ 0 │
│ Queries Slower │ 1 │
│ Queries with No Change │ 11 │
└─────────────────────────────────────────────┴────────────┘

[zhuqi-lucas]

It looks like no performance improvement for h2o_window benchmark result...

[alamb]

It looks like no performance improvement for h2o_window benchmark result...

Now that I think about it, the h2o benchmark may not have any string columns 🤔

Do the TPCH benchmarks read from CSV? Maybe we could just get some manual benchmarks ?

[zhuqi-lucas]

It looks like no performance improvement for h2o_window benchmark result...

Now that I think about it, the h2o benchmark may not have any string columns 🤔

Do the TPCH benchmarks read from CSV? Maybe we could just get some manual benchmarks ?

Thank you @alamb , this is a good point. Do some investigation from benchmark code now.

# Runs the tpch benchmark
run_tpch(){SCALE_FACTOR=$1if[ -z "$SCALE_FACTOR"]; then
echo "Internal error: Scale factor not specified"
exit 1
fi
TPCH_DIR="${DATA_DIR}/tpch_sf${SCALE_FACTOR}"RESULTS_FILE="${RESULTS_DIR}/tpch_sf${SCALE_FACTOR}.json"
echo "RESULTS_FILE: ${RESULTS_FILE}"
echo "Running tpch benchmark..."
# Optional query filter to run specific query
QUERY=$([ -n "$ARG3"] && echo "--query $ARG3" || echo "")
debug_run $CARGO_COMMAND --bin tpch -- benchmark datafusion --iterations 5 --path "${TPCH_DIR}" --prefer_hash_join "${PREFER_HASH_JOIN}" --format parquet -o "${RESULTS_FILE}" $QUERY
}

/// File format: `csv` or `parquet`#[structopt(short = "f", long = "format", default_value = "csv")]
file_format:String,

It looks like we default to parquet for tpch, but it also supports csv, i will try to create a PR to support csv from tpch benchmark parameters.

Because from the generator code for tpch, we also generate the CSV format, so it's reasonable for us to support CSV benchmark also, i will create a PR soon. Thanks

 # Create'tbl'(CSV format) data into $DATA_DIR if it does not already exist
FILE="${TPCH_DIR}/supplier.tbl"if test -f "${FILE}"; then
echo " tbl files exist ($FILE exists)."else
echo " creating tbl files with tpch_dbgen..."
docker run -v "${TPCH_DIR}":/data -it --rm ghcr.io/scalytics/tpch-docker:main -vf -s "${SCALE_FACTOR}"
fi

[alamb]

Marking as draft as I think this PR is no longer waiting on feedback and I am trying to make it easier to find PRs in need of review. Please mark it as ready for review when it is ready for another look

[zhuqi-lucas]

Thank you @alamb , i created a ticket for the support for csv tpch benchmark first.
#16370

Updated:

Submitted a PR for review:

#16373

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