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author | Liang-Chi Hsieh <viirya@appier.com> | 2015-07-30 17:45:30 +0800 |
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committer | Cheng Lian <lian@databricks.com> | 2015-07-30 17:45:30 +0800 |
commit | 6175d6cfe795fbd88e3ee713fac375038a3993a8 (patch) | |
tree | 8b3a54239608b5910e36bad44181860453b1b16f /sql | |
parent | 5ba2d44068b89fd8e81cfd24f49bf20d373f81b9 (diff) | |
download | spark-6175d6cfe795fbd88e3ee713fac375038a3993a8.tar.gz spark-6175d6cfe795fbd88e3ee713fac375038a3993a8.tar.bz2 spark-6175d6cfe795fbd88e3ee713fac375038a3993a8.zip |
[SPARK-8838] [SQL] Add config to enable/disable merging part-files when merging parquet schema
JIRA: https://issues.apache.org/jira/browse/SPARK-8838
Currently all part-files are merged when merging parquet schema. However, in case there are many part-files and we can make sure that all the part-files have the same schema as their summary file. If so, we provide a configuration to disable merging part-files when merging parquet schema.
In short, we need to merge parquet schema because different summary files may contain different schema. But the part-files are confirmed to have the same schema with summary files.
Author: Liang-Chi Hsieh <viirya@appier.com>
Closes #7238 from viirya/option_partfile_merge and squashes the following commits:
71d5b5f [Liang-Chi Hsieh] Merge remote-tracking branch 'upstream/master' into option_partfile_merge
8816f44 [Liang-Chi Hsieh] For comments.
dbc8e6b [Liang-Chi Hsieh] Merge remote-tracking branch 'upstream/master' into option_partfile_merge
afc2fa1 [Liang-Chi Hsieh] Merge remote-tracking branch 'upstream/master' into option_partfile_merge
d4ed7e6 [Liang-Chi Hsieh] Merge remote-tracking branch 'upstream/master' into option_partfile_merge
df43027 [Liang-Chi Hsieh] Get dataStatuses' partitions based on all paths.
4eb2f00 [Liang-Chi Hsieh] Use given parameter.
ea8f6e5 [Liang-Chi Hsieh] Correct the code comments.
a57be0e [Liang-Chi Hsieh] Merge part-files if there are no summary files.
47df981 [Liang-Chi Hsieh] Merge remote-tracking branch 'upstream/master' into option_partfile_merge
4caf293 [Liang-Chi Hsieh] Merge remote-tracking branch 'upstream/master' into option_partfile_merge
0e734e0 [Liang-Chi Hsieh] Use correct API.
3b6be5b [Liang-Chi Hsieh] Fix key not found.
4bdd7e0 [Liang-Chi Hsieh] Don't read footer files if we can skip them.
8bbebcb [Liang-Chi Hsieh] Figure out how to test the config.
bbd4ce7 [Liang-Chi Hsieh] Add config to enable/disable merging part-files when merging parquet schema.
Diffstat (limited to 'sql')
3 files changed, 52 insertions, 1 deletions
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala b/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala index cdb0c7a1c0..2564bbd207 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala @@ -247,6 +247,13 @@ private[spark] object SQLConf { "otherwise the schema is picked from the summary file or a random data file " + "if no summary file is available.") + val PARQUET_SCHEMA_RESPECT_SUMMARIES = booleanConf("spark.sql.parquet.respectSummaryFiles", + defaultValue = Some(false), + doc = "When true, we make assumption that all part-files of Parquet are consistent with " + + "summary files and we will ignore them when merging schema. Otherwise, if this is " + + "false, which is the default, we will merge all part-files. This should be considered " + + "as expert-only option, and shouldn't be enabled before knowing what it means exactly.") + val PARQUET_BINARY_AS_STRING = booleanConf("spark.sql.parquet.binaryAsString", defaultValue = Some(false), doc = "Some other Parquet-producing systems, in particular Impala and older versions of " + diff --git a/sql/core/src/main/scala/org/apache/spark/sql/parquet/ParquetRelation.scala b/sql/core/src/main/scala/org/apache/spark/sql/parquet/ParquetRelation.scala index 1a8176d8a8..b4337a48db 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/parquet/ParquetRelation.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/parquet/ParquetRelation.scala @@ -124,6 +124,9 @@ private[sql] class ParquetRelation( .map(_.toBoolean) .getOrElse(sqlContext.conf.getConf(SQLConf.PARQUET_SCHEMA_MERGING_ENABLED)) + private val mergeRespectSummaries = + sqlContext.conf.getConf(SQLConf.PARQUET_SCHEMA_RESPECT_SUMMARIES) + private val maybeMetastoreSchema = parameters .get(ParquetRelation.METASTORE_SCHEMA) .map(DataType.fromJson(_).asInstanceOf[StructType]) @@ -421,7 +424,21 @@ private[sql] class ParquetRelation( val filesToTouch = if (shouldMergeSchemas) { // Also includes summary files, 'cause there might be empty partition directories. - (metadataStatuses ++ commonMetadataStatuses ++ dataStatuses).toSeq + + // If mergeRespectSummaries config is true, we assume that all part-files are the same for + // their schema with summary files, so we ignore them when merging schema. + // If the config is disabled, which is the default setting, we merge all part-files. + // In this mode, we only need to merge schemas contained in all those summary files. + // You should enable this configuration only if you are very sure that for the parquet + // part-files to read there are corresponding summary files containing correct schema. + + val needMerged: Seq[FileStatus] = + if (mergeRespectSummaries) { + Seq() + } else { + dataStatuses + } + (metadataStatuses ++ commonMetadataStatuses ++ needMerged).toSeq } else { // Tries any "_common_metadata" first. Parquet files written by old versions or Parquet // don't have this. diff --git a/sql/core/src/test/scala/org/apache/spark/sql/parquet/ParquetQuerySuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/parquet/ParquetQuerySuite.scala index c037faf4cf..a95f70f2bb 100644 --- a/sql/core/src/test/scala/org/apache/spark/sql/parquet/ParquetQuerySuite.scala +++ b/sql/core/src/test/scala/org/apache/spark/sql/parquet/ParquetQuerySuite.scala @@ -17,10 +17,13 @@ package org.apache.spark.sql.parquet +import java.io.File + import org.apache.hadoop.fs.Path import org.apache.spark.sql.types._ import org.apache.spark.sql.{QueryTest, Row, SQLConf} +import org.apache.spark.util.Utils /** * A test suite that tests various Parquet queries. @@ -123,6 +126,30 @@ class ParquetQuerySuite extends QueryTest with ParquetTest { } } + test("Enabling/disabling merging partfiles when merging parquet schema") { + def testSchemaMerging(expectedColumnNumber: Int): Unit = { + withTempDir { dir => + val basePath = dir.getCanonicalPath + sqlContext.range(0, 10).toDF("a").write.parquet(new Path(basePath, "foo=1").toString) + sqlContext.range(0, 10).toDF("b").write.parquet(new Path(basePath, "foo=2").toString) + // delete summary files, so if we don't merge part-files, one column will not be included. + Utils.deleteRecursively(new File(basePath + "/foo=1/_metadata")) + Utils.deleteRecursively(new File(basePath + "/foo=1/_common_metadata")) + assert(sqlContext.read.parquet(basePath).columns.length === expectedColumnNumber) + } + } + + withSQLConf(SQLConf.PARQUET_SCHEMA_MERGING_ENABLED.key -> "true", + SQLConf.PARQUET_SCHEMA_RESPECT_SUMMARIES.key -> "true") { + testSchemaMerging(2) + } + + withSQLConf(SQLConf.PARQUET_SCHEMA_MERGING_ENABLED.key -> "true", + SQLConf.PARQUET_SCHEMA_RESPECT_SUMMARIES.key -> "false") { + testSchemaMerging(3) + } + } + test("Enabling/disabling schema merging") { def testSchemaMerging(expectedColumnNumber: Int): Unit = { withTempDir { dir => |