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Posted to reviews@spark.apache.org by "monkeyboy123 (via GitHub)" <gi...@apache.org> on 2023/08/07 09:20:37 UTC
[GitHub] [spark] monkeyboy123 opened a new pull request, #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
monkeyboy123 opened a new pull request, #42376:
URL: https://github.com/apache/spark/pull/42376
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Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
### Why are the changes needed?
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It causes performance regression.
### Does this PR introduce _any_ user-facing change?
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yes,
sql like this:
```
select tmp.*
from
(select
device_id, ads_id,
from_json(regexp_replace(device_personas, '(?<=(\\\\\\{|,))"device_', '"user_device_'), ${device_schema}) as tmp
from input )
${device_schema} includes more than 100 fields.
```
before this pr:
it takes 43 minutes.
<img width="597" alt="image" src="https://github.com/apache/spark/assets/9074114/865314de-a048-4c19-9dfe-552fb3cc2ddc">
After this pr:
it takes 6 minutes.
<img width="642" alt="image" src="https://github.com/apache/spark/assets/9074114/a374e828-2582-4fbb-8f32-c8e640b8c2e7">
If Rule: OptimizeJsonExprs not been applied,
in physical plan : ProjectExec
function: InterpretedUnsafeProjection.createProjection or GenerateUnsafeProjection.generate will eliminate common expression,so that regexp_replace will been computed just one time.
If Rule: OptimizeJsonExprs been applied, regexp_replace will been computed as many times as numbers of ${device_schema} fields .
BTW, it hard to find root cause, in this examples, it takes me 2 days to find out the root cause.
### How was this patch tested?
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NO, it just a rule optimization for OptimizeJsonExprs
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[GitHub] [spark] monkeyboy123 commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1672814487
It seems like it happens in spark 3.1.1. It has been fixed in spark 3.4.x.
@cloud-fan @wangyum
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[GitHub] [spark] wangyum closed pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "wangyum (via GitHub)" <gi...@apache.org>.
wangyum closed pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
URL: https://github.com/apache/spark/pull/42376
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[GitHub] [spark] monkeyboy123 commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1669480999
> cc @wangyum do you have any ideas? It seems any optimization that changes the expression shape may break common subexpression elimination (CSE). It's hard to come up with a good cost model to fix it. I think a better idea is to make CSE a plan-level optimization, so that we can find all common subexpressions before optimizing expressions. But it's hard to do.
>
> @monkeyboy123 is it possible to rewrite your query and use subquery alias or CTE to hold the expression result, to avoid repeated execution? or you can disable this optimization by setting `spark.sql.optimizer.excludedRules` to include this rule.
I can disable this optimization by setting spark.sql.optimizer.enableJsonExpressionOptimization to false, but i think it is a common case that someone will encounter, maybe can we add more case ,such as RegExpReplace or RegExpExtract etc, to deal with this case?
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[GitHub] [spark] monkeyboy123 closed pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 closed pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
URL: https://github.com/apache/spark/pull/42376
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[GitHub] [spark] monkeyboy123 commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1668104156
retest this please
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[GitHub] [spark] wangyum commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "wangyum (via GitHub)" <gi...@apache.org>.
wangyum commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1673275286
Thanks @monkeyboy123. Please upgrade your Spark to the latest version.
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[GitHub] [spark] wankunde commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "wankunde (via GitHub)" <gi...@apache.org>.
wankunde commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1674441218
I think we can reuse the result of the same regexp_replace functions, for example, we can reuse the result of `regexp_replace(s, 'a', 'x')` :
```sql
SELECT from_json(regexp_replace(s, 'a', 'x'), 'x INT, b DOUBLE').x,
from_json(regexp_replace(s, 'a', 'x'), 'x INT, b DOUBLE').b
FROM values('{"a":1, "b":0.8}') t(s)
```
Filed another PR for this purpose: https://github.com/apache/spark/pull/42450
cc @cloud-fan @wangyum
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[GitHub] [spark] monkeyboy123 commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1668672646
gently ping @viirya Could you help me to reivew it? also cc @cloud-fan
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[GitHub] [spark] wangyum commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "wangyum (via GitHub)" <gi...@apache.org>.
wangyum commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1671438383
@monkeyboy123 Have you enabled `spark.sql.optimizer.collapseProjectAlwaysInline`?
```scala
Seq("""{"a":1, "b":0.8}""").toDF("s").write.saveAsTable("t")
val df = sql(
"""
|SELECT j.*
|FROM (SELECT from_json(regexp_replace(s, 'a', 'new_a'), 'new_a INT, b DOUBLE') AS j
| FROM t) tmp
|""".stripMargin)
df.explain(true)
```
`set spark.sql.optimizer.collapseProjectAlwaysInline=false`:
```
== Optimized Logical Plan ==
Project [j#17.new_a AS new_a#20, j#17.b AS b#21]
+- Project [from_json(StructField(new_a,IntegerType,true), StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)) AS j#17]
+- Relation spark_catalog.default.t[s#18] parquet
== Physical Plan ==
*(2) Project [j#17.new_a AS new_a#20, j#17.b AS b#21]
+- Project [from_json(StructField(new_a,IntegerType,true), StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)) AS j#17]
+- *(1) ColumnarToRow
+- FileScan parquet spark_catalog.default.t[s#18] Batched: true, DataFilters: [], Format: Parquet, Location: InMemoryFileIndex(1 paths)[file:/Users/yumwang/spark/spark-warehouse/org.apache.spark..., PartitionFilters: [], PushedFilters: [], ReadSchema: struct<s:string>
```
`set spark.sql.optimizer.collapseProjectAlwaysInline=true`:
```
== Optimized Logical Plan ==
Project [from_json(StructField(new_a,IntegerType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).new_a AS new_a#20, from_json(StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).b AS b#21]
+- Relation spark_catalog.default.t[s#18] parquet
== Physical Plan ==
Project [from_json(StructField(new_a,IntegerType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).new_a AS new_a#20, from_json(StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).b AS b#21]
+- *(1) ColumnarToRow
+- FileScan parquet spark_catalog.default.t[s#18] Batched: true, DataFilters: [], Format: Parquet, Location: InMemoryFileIndex(1 paths)[file:/Users/yumwang/spark/spark-warehouse/org.apache.spark..., PartitionFilters: [], PushedFilters: [], ReadSchema: struct<s:string>
```
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[GitHub] [spark] monkeyboy123 commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1671598637
>
@wangyum Actually, i encounter this problem in spark 3.1.1, but i can do a check in spark 3.4.x.
> @monkeyboy123 Have you enabled `spark.sql.optimizer.collapseProjectAlwaysInline`?
>
> ```scala
> Seq("""{"a":1, "b":0.8}""").toDF("s").write.saveAsTable("t")
> val df = sql(
> """
> |SELECT j.*
> |FROM (SELECT from_json(regexp_replace(s, 'a', 'new_a'), 'new_a INT, b DOUBLE') AS j
> | FROM t) tmp
> |""".stripMargin)
> df.explain(true)
> ```
>
> `set spark.sql.optimizer.collapseProjectAlwaysInline=false`:
>
> ```
> == Optimized Logical Plan ==
> Project [j#17.new_a AS new_a#20, j#17.b AS b#21]
> +- Project [from_json(StructField(new_a,IntegerType,true), StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)) AS j#17]
> +- Relation spark_catalog.default.t[s#18] parquet
>
> == Physical Plan ==
> *(2) Project [j#17.new_a AS new_a#20, j#17.b AS b#21]
> +- Project [from_json(StructField(new_a,IntegerType,true), StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)) AS j#17]
> +- *(1) ColumnarToRow
> +- FileScan parquet spark_catalog.default.t[s#18] Batched: true, DataFilters: [], Format: Parquet, Location: InMemoryFileIndex(1 paths)[file:/Users/yumwang/spark/spark-warehouse/org.apache.spark..., PartitionFilters: [], PushedFilters: [], ReadSchema: struct<s:string>
> ```
>
> `set spark.sql.optimizer.collapseProjectAlwaysInline=true`:
>
> ```
> == Optimized Logical Plan ==
> Project [from_json(StructField(new_a,IntegerType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).new_a AS new_a#20, from_json(StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).b AS b#21]
> +- Relation spark_catalog.default.t[s#18] parquet
>
> == Physical Plan ==
> Project [from_json(StructField(new_a,IntegerType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).new_a AS new_a#20, from_json(StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).b AS b#21]
> +- *(1) ColumnarToRow
> +- FileScan parquet spark_catalog.default.t[s#18] Batched: true, DataFilters: [], Format: Parquet, Location: InMemoryFileIndex(1 paths)[file:/Users/yumwang/spark/spark-warehouse/org.apache.spark..., PartitionFilters: [], PushedFilters: [], ReadSchema: struct<s:string>
> ```
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[GitHub] [spark] cloud-fan commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "cloud-fan (via GitHub)" <gi...@apache.org>.
cloud-fan commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1669240688
cc @wangyum do you have any ideas? It seems any optimization that changes the expression shape may break common subexpression elimination (CSE). It's hard to come up with a good cost model to fix it. I think a better idea is to make CSE a plan-level optimization, so that we can find all common subexpressions before optimizing expressions. But it's hard to do.
@monkeyboy123 is it possible to rewrite your query and use subquery alias or CTE to hold the expression result, to avoid repeated execution? or you can disable this optimization by setting `spark.sql.optimizer.excludedRules` to include this rule.
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[GitHub] [spark] monkeyboy123 commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1671602098
> @monkeyboy123 Have you enabled `spark.sql.optimizer.collapseProjectAlwaysInline`?
@wangyum Actually, i encounter this problem in spark 3.1.1, but i can do a check in spark 3.4.x.
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[GitHub] [spark] monkeyboy123 commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1671600387
> @monkeyboy123 Have you enabled `spark.sql.optimizer.collapseProjectAlwaysInline`?
@wangyum Actually, i encounter this problem in spark 3.1.1, but i can do a check in spark 3.4.x.
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[GitHub] [spark] monkeyboy123 commented on pull request #42376: [SPARK-44700][SQL] Rule OptimizeCsvJsonExprs should not be applied to expression like from_json(regexp_replace)
Posted by "monkeyboy123 (via GitHub)" <gi...@apache.org>.
monkeyboy123 commented on PR #42376:
URL: https://github.com/apache/spark/pull/42376#issuecomment-1671596282
> Project [from_json(StructField(new_a,IntegerType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).new_a AS new_a#20, from_json(StructField(b,DoubleType,true), regexp_replace(s#18, a, new_a, 1), Some(America/Los_Angeles)).b AS b#21]
@wangyum Actually, i encounter this problem in spark 3.1.1, but i can do a check in spark 3.4.x.
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