This PR addresses two issues:
- Self join does not work in SQL Generation
- When creating new instances for `LogicalRelation`, `metastoreTableIdentifier` is lost.
liancheng Could you please review the code changes? Thank you!
Author: gatorsmile <gatorsmile@gmail.com>
Closes#11084 from gatorsmile/selfJoinInSQLGen.
Some analysis rules generate aliases or auxiliary attribute references with the same name but different expression IDs. For example, `ResolveAggregateFunctions` introduces `havingCondition` and `aggOrder`, and `DistinctAggregationRewriter` introduces `gid`.
This is OK for normal query execution since these attribute references get expression IDs. However, it's troublesome when converting resolved query plans back to SQL query strings since expression IDs are erased.
Here's an example Spark 1.6.0 snippet for illustration:
```scala
sqlContext.range(10).select('id as 'a, 'id as 'b).registerTempTable("t")
sqlContext.sql("SELECT SUM(a) FROM t GROUP BY a, b ORDER BY COUNT(a), COUNT(b)").explain(true)
```
The above code produces the following resolved plan:
```
== Analyzed Logical Plan ==
_c0: bigint
Project [_c0#101L]
+- Sort [aggOrder#102L ASC,aggOrder#103L ASC], true
+- Aggregate [a#47L,b#48L], [(sum(a#47L),mode=Complete,isDistinct=false) AS _c0#101L,(count(a#47L),mode=Complete,isDistinct=false) AS aggOrder#102L,(count(b#48L),mode=Complete,isDistinct=false) AS aggOrder#103L]
+- Subquery t
+- Project [id#46L AS a#47L,id#46L AS b#48L]
+- LogicalRDD [id#46L], MapPartitionsRDD[44] at range at <console>:26
```
Here we can see that both aggregate expressions in `ORDER BY` are extracted into an `Aggregate` operator, and both of them are named `aggOrder` with different expression IDs.
The solution is to automatically add the expression IDs into the attribute name for the Alias and AttributeReferences that are generated by Analyzer in SQL Generation.
In this PR, it also resolves another issue. Users could use the same name as the internally generated names. The duplicate names should not cause name ambiguity. When resolving the column, Catalyst should not pick the column that is internally generated.
Could you review the solution? marmbrus liancheng
I did not set the newly added flag for all the alias and attribute reference generated by Analyzers. Please let me know if I should do it? Thank you!
Author: gatorsmile <gatorsmile@gmail.com>
Closes#11050 from gatorsmile/namingConflicts.
The patch for SPARK-8964 ("use Exchange to perform shuffle in Limit" / #7334) inadvertently broke the planning of the TakeOrderedAndProject operator: because ReturnAnswer was the new root of the query plan, the TakeOrderedAndProject rule was unable to match before BasicOperators.
This patch fixes this by moving the `TakeOrderedAndCollect` and `CollectLimit` rules into the same strategy.
In addition, I made changes to the TakeOrderedAndProject operator in order to make its `doExecute()` method lazy and added a new TakeOrderedAndProjectSuite which tests the new code path.
/cc davies and marmbrus for review.
Author: Josh Rosen <joshrosen@databricks.com>
Closes#11145 from JoshRosen/take-ordered-and-project-fix.
WIP: running tests. Code needs a bit of clean up.
This patch completes the vectorized decoding with the goal of passing the existing
tests. There is still more patches to support the rest of the format spec, even
just for flat schemas.
This patch adds a new flag to enable the vectorized decoding. Tests were updated
to try with both modes where applicable.
Once this is working well, we can remove the previous code path.
Author: Nong Li <nong@databricks.com>
Closes#11055 from nongli/spark-12992-2.
JIRA: https://issues.apache.org/jira/browse/SPARK-12850
This PR is to support bucket pruning when the predicates are `EqualTo`, `EqualNullSafe`, `IsNull`, `In`, and `InSet`.
Like HIVE, in this PR, the bucket pruning works when the bucketing key has one and only one column.
So far, I do not find a way to verify how many buckets are actually scanned. However, I did verify it when doing the debug. Could you provide a suggestion how to do it properly? Thank you! cloud-fan yhuai rxin marmbrus
BTW, we can add more cases to support complex predicate including `Or` and `And`. Please let me know if I should do it in this PR.
Maybe we also need to add test cases to verify if bucket pruning works well for each data type.
Author: gatorsmile <gatorsmile@gmail.com>
Closes#10942 from gatorsmile/pruningBuckets.
Spark SQL should collapse adjacent `Repartition` operators and only keep the last one.
Author: Josh Rosen <joshrosen@databricks.com>
Closes#11064 from JoshRosen/collapse-repartition.
As benchmarked and discussed here: https://github.com/apache/spark/pull/10786/files#r50038294, benefits from codegen, the declarative aggregate function could be much faster than imperative one.
Author: Davies Liu <davies@databricks.com>
Closes#10960 from davies/stddev.
It is not valid to call `toAttribute` on a `NamedExpression` unless we know for sure that the child produced that `NamedExpression`. The current code worked fine when the grouping expressions were simple, but when they were a derived value this blew up at execution time.
Author: Michael Armbrust <michael@databricks.com>
Closes#11013 from marmbrus/groupByFunction-master.
JIRA: https://issues.apache.org/jira/browse/SPARK-12705
**Scope:**
This PR is a general fix for sorting reference resolution when the child's `outputSet` does not have the order-by attributes (called, *missing attributes*):
- UnaryNode support is limited to `Project`, `Window`, `Aggregate`, `Distinct`, `Filter`, `RepartitionByExpression`.
- We will not try to resolve the missing references inside a subquery, unless the outputSet of this subquery contains it.
**General Reference Resolution Rules:**
- Jump over the nodes with the following types: `Distinct`, `Filter`, `RepartitionByExpression`. Do not need to add missing attributes. The reason is their `outputSet` is decided by their `inputSet`, which is the `outputSet` of their children.
- Group-by expressions in `Aggregate`: missing order-by attributes are not allowed to be added into group-by expressions since it will change the query result. Thus, in RDBMS, it is not allowed.
- Aggregate expressions in `Aggregate`: if the group-by expressions in `Aggregate` contains the missing attributes but aggregate expressions do not have it, just add them into the aggregate expressions. This can resolve the analysisExceptions thrown by the three TCPDS queries.
- `Project` and `Window` are special. We just need to add the missing attributes to their `projectList`.
**Implementation:**
1. Traverse the whole tree in a pre-order manner to find all the resolvable missing order-by attributes.
2. Traverse the whole tree in a post-order manner to add the found missing order-by attributes to the node if their `inputSet` contains the attributes.
3. If the origins of the missing order-by attributes are different nodes, each pass only resolves the missing attributes that are from the same node.
**Risk:**
Low. This rule will be trigger iff ```!s.resolved && child.resolved``` is true. Thus, very few cases are affected.
Author: gatorsmile <gatorsmile@gmail.com>
Closes#10678 from gatorsmile/sortWindows.
This patch changes Spark's build to make Scala 2.11 the default Scala version. To be clear, this does not mean that Spark will stop supporting Scala 2.10: users will still be able to compile Spark for Scala 2.10 by following the instructions on the "Building Spark" page; however, it does mean that Scala 2.11 will be the default Scala version used by our CI builds (including pull request builds).
The Scala 2.11 compiler is faster than 2.10, so I think we'll be able to look forward to a slight speedup in our CI builds (it looks like it's about 2X faster for the Maven compile-only builds, for instance).
After this patch is merged, I'll update Jenkins to add new compile-only jobs to ensure that Scala 2.10 compilation doesn't break.
Author: Josh Rosen <joshrosen@databricks.com>
Closes#10608 from JoshRosen/SPARK-6363.
And ClientWrapper -> HiveClientImpl.
I have some followup pull requests to introduce a new internal catalog, and I think this new naming reflects better the functionality of the two classes.
Author: Reynold Xin <rxin@databricks.com>
Closes#10981 from rxin/SPARK-13076.
JIRA: https://issues.apache.org/jira/browse/SPARK-12968
Implement command to set current database.
Author: Liang-Chi Hsieh <viirya@gmail.com>
Author: Liang-Chi Hsieh <viirya@appier.com>
Closes#10916 from viirya/ddl-use-database.
This PR moves all the functionality provided by the SparkSQLParser/ExtendedHiveQlParser to the new Parser hierarchy (SparkQl/HiveQl). This also improves the current SET command parsing: the current implementation swallows ```set role ...``` and ```set autocommit ...``` commands, this PR respects these commands (and passes them on to Hive).
This PR and https://github.com/apache/spark/pull/10723 end the use of Parser-Combinator parsers for SQL parsing. As a result we can also remove the ```AbstractSQLParser``` in Catalyst.
The PR is marked WIP as long as it doesn't pass all tests.
cc rxin viirya winningsix (this touches https://github.com/apache/spark/pull/10144)
Author: Herman van Hovell <hvanhovell@questtec.nl>
Closes#10905 from hvanhovell/SPARK-12866.
This PR is a follow-up of PR #10541. It integrates the newly introduced SQL generation feature with native view to make native view canonical.
In this PR, a new SQL option `spark.sql.nativeView.canonical` is added. When this option and `spark.sql.nativeView` are both `true`, Spark SQL tries to handle `CREATE VIEW` DDL statements using SQL query strings generated from view definition logical plans. If we failed to map the plan to SQL, we fallback to the original native view approach.
One important issue this PR fixes is that, now we can use CTE when defining a view. Originally, when native view is turned on, we wrap the view definition text with an extra `SELECT`. However, HiveQL parser doesn't allow CTE appearing as a subquery. Namely, something like this is disallowed:
```sql
SELECT n
FROM (
WITH w AS (SELECT 1 AS n)
SELECT * FROM w
) v
```
This PR fixes this issue because the extra `SELECT` is no longer needed (also, CTE expressions are inlined as subqueries during analysis phase, thus there won't be CTE expressions in the generated SQL query string).
Author: Cheng Lian <lian@databricks.com>
Author: Yin Huai <yhuai@databricks.com>
Closes#10733 from liancheng/spark-12728.integrate-sql-gen-with-native-view.
This patch adds support for complex types for ColumnarBatch. ColumnarBatch supports structs
and arrays. There is a simple mapping between the richer catalyst types to these two. Strings
are treated as an array of bytes.
ColumnarBatch will contain a column for each node of the schema. Non-complex schemas consists
of just leaf nodes. Structs represent an internal node with one child for each field. Arrays
are internal nodes with one child. Structs just contain nullability. Arrays contain offsets
and lengths into the child array. This structure is able to handle arbitrary nesting. It has
the key property that we maintain columnar throughout and that primitive types are only stored
in the leaf nodes and contiguous across rows. For example, if the schema is
```
array<array<int>>
```
There are three columns in the schema. The internal nodes each have one children. The leaf node contains all the int data stored consecutively.
As part of this, this patch adds append APIs in addition to the Put APIs (e.g. putLong(rowid, v)
vs appendLong(v)). These APIs are necessary when the batch contains variable length elements.
The vectors are not fixed length and will grow as necessary. This should make the usage a lot
simpler for the writer.
Author: Nong Li <nong@databricks.com>
Closes#10820 from nongli/spark-12854.
This PR adds a new table option (`skip_hive_metadata`) that'd allow the user to skip storing the table metadata in hive metadata format. While this could be useful in general, the specific use-case for this change is that Hive doesn't handle wide schemas well (see https://issues.apache.org/jira/browse/SPARK-12682 and https://issues.apache.org/jira/browse/SPARK-6024) which in turn prevents such tables from being queried in SparkSQL.
Author: Sameer Agarwal <sameer@databricks.com>
Closes#10826 from sameeragarwal/skip-hive-metadata.
When users are using `partitionBy` and `bucketBy` at the same time, some bucketing columns might be part of partitioning columns. For example,
```
df.write
.format(source)
.partitionBy("i")
.bucketBy(8, "i", "k")
.saveAsTable("bucketed_table")
```
However, in the above case, adding column `i` into `bucketBy` is useless. It is just wasting extra CPU when reading or writing bucket tables. Thus, like Hive, we can issue an exception and let users do the change.
Also added a test case for checking if the information of `sortBy` and `bucketBy` columns are correctly saved in the metastore table.
Could you check if my understanding is correct? cloud-fan rxin marmbrus Thanks!
Author: gatorsmile <gatorsmile@gmail.com>
Closes#10891 from gatorsmile/commonKeysInPartitionByBucketBy.
ErrorPositionSuite and one of the HiveComparisonTest tests have been consistently failing on the Hadoop 2.3 SBT build (but on no other builds). I believe that this is due to test isolation issues (e.g. tests sharing state via the sets of temporary tables that are registered to TestHive).
This patch attempts to improve the isolation of these tests in order to address this issue.
Author: Josh Rosen <joshrosen@databricks.com>
Closes#10884 from JoshRosen/fix-failing-hadoop-2.3-hive-tests.
When users turn off bucketing in SQLConf, we should issue some messages to tell users these operations will be converted to normal way.
Also added a test case for this scenario and fixed the helper function.
Do you think this PR is helpful when using bucket tables? cloud-fan Thank you!
Author: gatorsmile <gatorsmile@gmail.com>
Closes#10870 from gatorsmile/bucketTableWritingTestcases.
The current parser turns a decimal literal, for example ```12.1```, into a Double. The problem with this approach is that we convert an exact literal into a non-exact ```Double```. The PR changes this behavior, a Decimal literal is now converted into an extact ```BigDecimal```.
The behavior for scientific decimals, for example ```12.1e01```, is unchanged. This will be converted into a Double.
This PR replaces the ```BigDecimal``` literal by a ```Double``` literal, because the ```BigDecimal``` is the default now. You can use the double literal by appending a 'D' to the value, for instance: ```3.141527D```
cc davies rxin
Author: Herman van Hovell <hvanhovell@questtec.nl>
Closes#10796 from hvanhovell/SPARK-12848.
The existing `Union` logical operator only supports two children. Thus, adding a new logical operator `Unions` which can have arbitrary number of children to replace the existing one.
`Union` logical plan is a binary node. However, a typical use case for union is to union a very large number of input sources (DataFrames, RDDs, or files). It is not uncommon to union hundreds of thousands of files. In this case, our optimizer can become very slow due to the large number of logical unions. We should change the Union logical plan to support an arbitrary number of children, and add a single rule in the optimizer to collapse all adjacent `Unions` into a single `Unions`. Note that this problem doesn't exist in physical plan, because the physical `Unions` already supports arbitrary number of children.
Author: gatorsmile <gatorsmile@gmail.com>
Author: xiaoli <lixiao1983@gmail.com>
Author: Xiao Li <xiaoli@Xiaos-MacBook-Pro.local>
Closes#10577 from gatorsmile/unionAllMultiChildren.
Currently, HiveTableScan runs with getCallSite which is really expensive and shows up when scanning through large table with partitions (e.g TPC-DS) which slows down the overall runtime of the job. It would be good to consider having dummyCallSite in HiveTableScan.
Author: Rajesh Balamohan <rbalamohan@apache.org>
Closes#10825 from rajeshbalamohan/SPARK-12898.
for normal parquet file without bucket, it's file name ends with a jobUUID which maybe all numbers and mistakeny regarded as bucket id. This PR improves the format of bucket id in file name by using a different seperator, `_`, so that the regex is more robust.
Author: Wenchen Fan <wenchen@databricks.com>
Closes#10799 from cloud-fan/fix-bucket.
Based on discussions in #10801, I'm submitting a pull request to rename ParserDialect to ParserInterface.
Author: Reynold Xin <rxin@databricks.com>
Closes#10817 from rxin/SPARK-12889.
Right now, the bucket tests are kind of hard to understand, this PR simplifies them and add more commetns.
Author: Wenchen Fan <wenchen@databricks.com>
Closes#10813 from cloud-fan/bucket-comment.
This pull request removes the public developer parser API for external parsers. Given everything a parser depends on (e.g. logical plans and expressions) are internal and not stable, external parsers will break with every release of Spark. It is a bad idea to create the illusion that Spark actually supports pluggable parsers. In addition, this also reduces incentives for 3rd party projects to contribute parse improvements back to Spark.
Author: Reynold Xin <rxin@databricks.com>
Closes#10801 from rxin/SPARK-12855.
This is the initial work for whole stage codegen, it support Projection/Filter/Range, we will continue work on this to support more physical operators.
A micro benchmark show that a query with range, filter and projection could be 3X faster then before.
It's turned on by default. For a tree that have at least two chained plans, a WholeStageCodegen will be inserted into it, for example, the following plan
```
Limit 10
+- Project [(id#5L + 1) AS (id + 1)#6L]
+- Filter ((id#5L & 1) = 1)
+- Range 0, 1, 4, 10, [id#5L]
```
will be translated into
```
Limit 10
+- WholeStageCodegen
+- Project [(id#1L + 1) AS (id + 1)#2L]
+- Filter ((id#1L & 1) = 1)
+- Range 0, 1, 4, 10, [id#1L]
```
Here is the call graph to generate Java source for A and B (A support codegen, but B does not):
```
* WholeStageCodegen Plan A FakeInput Plan B
* =========================================================================
*
* -> execute()
* |
* doExecute() --------> produce()
* |
* doProduce() -------> produce()
* |
* doProduce() ---> execute()
* |
* consume()
* doConsume() ------------|
* |
* doConsume() <----- consume()
```
A SparkPlan that support codegen need to implement doProduce() and doConsume():
```
def doProduce(ctx: CodegenContext): (RDD[InternalRow], String)
def doConsume(ctx: CodegenContext, child: SparkPlan, input: Seq[ExprCode]): String
```
Author: Davies Liu <davies@databricks.com>
Closes#10735 from davies/whole2.
This PR adds the support to read bucketed tables, and correctly populate `outputPartitioning`, so that we can avoid shuffle for some cases.
TODO(follow-up PRs):
* bucket pruning
* avoid shuffle for bucketed table join when use any super-set of the bucketing key.
(we should re-visit it after https://issues.apache.org/jira/browse/SPARK-12704 is fixed)
* recognize hive bucketed table
Author: Wenchen Fan <wenchen@databricks.com>
Closes#10604 from cloud-fan/bucket-read.
In this PR the new CatalystQl parser stack reaches grammar parity with the old Parser-Combinator based SQL Parser. This PR also replaces all uses of the old Parser, and removes it from the code base.
Although the existing Hive and SQL parser dialects were mostly the same, some kinks had to be worked out:
- The SQL Parser allowed syntax like ```APPROXIMATE(0.01) COUNT(DISTINCT a)```. In order to make this work we needed to hardcode approximate operators in the parser, or we would have to create an approximate expression. ```APPROXIMATE_COUNT_DISTINCT(a, 0.01)``` would also do the job and is much easier to maintain. So, this PR **removes** this keyword.
- The old SQL Parser supports ```LIMIT``` clauses in nested queries. This is **not supported** anymore. See https://github.com/apache/spark/pull/10689 for the rationale for this.
- Hive has a charset name char set literal combination it supports, for instance the following expression ```_ISO-8859-1 0x4341464562616265``` would yield this string: ```CAFEbabe```. Hive will only allow charset names to start with an underscore. This is quite annoying in spark because as soon as you use a tuple names will start with an underscore. In this PR we **remove** this feature from the parser. It would be quite easy to implement such a feature as an Expression later on.
- Hive and the SQL Parser treat decimal literals differently. Hive will turn any decimal into a ```Double``` whereas the SQL Parser would convert a non-scientific decimal into a ```BigDecimal```, and would turn a scientific decimal into a Double. We follow Hive's behavior here. The new parser supports a big decimal literal, for instance: ```81923801.42BD```, which can be used when a big decimal is needed.
cc rxin viirya marmbrus yhuai cloud-fan
Author: Herman van Hovell <hvanhovell@questtec.nl>
Closes#10745 from hvanhovell/SPARK-12575-2.
This PR makes bucketing and exchange share one common hash algorithm, so that we can guarantee the data distribution is same between shuffle and bucketed data source, which enables us to only shuffle one side when join a bucketed table and a normal one.
This PR also fixes the tests that are broken by the new hash behaviour in shuffle.
Author: Wenchen Fan <wenchen@databricks.com>
Closes#10703 from cloud-fan/use-hash-expr-in-shuffle.
Fix the style violation (space before , and :).
This PR is a followup for #10643 and rework of #10685 .
Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>
Closes#10732 from sarutak/SPARK-12692-followup-sql.
cloud-fan Can you please take a look ?
In this case, we are failing during check analysis while validating the aggregation expression. I have added a semanticEquals for HiveGenericUDF to fix this. Please let me know if this is the right way to address this issue.
Author: Dilip Biswal <dbiswal@us.ibm.com>
Closes#10520 from dilipbiswal/spark-12558.
This PR implements SQL generation support for persisted data source tables. A new field `metastoreTableIdentifier: Option[TableIdentifier]` is added to `LogicalRelation`. When a `LogicalRelation` representing a persisted data source relation is created, this field holds the database name and table name of the relation.
Author: Cheng Lian <lian@databricks.com>
Closes#10712 from liancheng/spark-12724-datasources-sql-gen.
Fix the style violation (space before , and :).
This PR is a followup for #10643.
Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>
Closes#10718 from sarutak/SPARK-12692-followup-sql.
```
[info] Exception encountered when attempting to run a suite with class name:
org.apache.spark.sql.hive.LogicalPlanToSQLSuite *** ABORTED *** (325 milliseconds)
[info] org.apache.spark.sql.AnalysisException: Table `t1` already exists.;
[info] at org.apache.spark.sql.DataFrameWriter.saveAsTable(DataFrameWriter.scala:296)
[info] at org.apache.spark.sql.DataFrameWriter.saveAsTable(DataFrameWriter.scala:285)
[info] at org.apache.spark.sql.hive.LogicalPlanToSQLSuite.beforeAll(LogicalPlanToSQLSuite.scala:33)
[info] at org.scalatest.BeforeAndAfterAll$class.beforeAll(BeforeAndAfterAll.scala:187)
[info] at org.apache.spark.sql.hive.LogicalPlanToSQLSuite.beforeAll(LogicalPlanToSQLSuite.scala:23)
[info] at org.scalatest.BeforeAndAfterAll$class.run(BeforeAndAfterAll.scala:253)
[info] at org.apache.spark.sql.hive.LogicalPlanToSQLSuite.run(LogicalPlanToSQLSuite.scala:23)
[info] at org.scalatest.tools.Framework.org$scalatest$tools$Framework$$runSuite(Framework.scala:462)
[info] at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:671)
[info] at sbt.ForkMain$Run$2.call(ForkMain.java:296)
[info] at sbt.ForkMain$Run$2.call(ForkMain.java:286)
[info] at java.util.concurrent.FutureTask.run(FutureTask.java:266)
[info] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
[info] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
[info] at java.lang.Thread.run(Thread.java:745)
```
/cc liancheng
Author: wangfei <wangfei_hello@126.com>
Closes#10682 from scwf/fix-test.
The PR allows us to use the new SQL parser to parse SQL expressions such as: ```1 + sin(x*x)```
We enable this functionality in this PR, but we will not start using this actively yet. This will be done as soon as we have reached grammar parity with the existing parser stack.
cc rxin
Author: Herman van Hovell <hvanhovell@questtec.nl>
Closes#10649 from hvanhovell/SPARK-12576.
Turn import ordering violations into build errors, plus a few adjustments
to account for how the checker behaves. I'm a little on the fence about
whether the existing code is right, but it's easier to appease the checker
than to discuss what's the more correct order here.
Plus a few fixes to imports that cropped in since my recent cleanups.
Author: Marcelo Vanzin <vanzin@cloudera.com>
Closes#10612 from vanzin/SPARK-3873-enable.
This PR tries to enable Spark SQL to convert resolved logical plans back to SQL query strings. For now, the major use case is to canonicalize Spark SQL native view support. The major entry point is `SQLBuilder.toSQL`, which returns an `Option[String]` if the logical plan is recognized.
The current version is still in WIP status, and is quite limited. Known limitations include:
1. The logical plan must be analyzed but not optimized
The optimizer erases `Subquery` operators, which contain necessary scope information for SQL generation. Future versions should be able to recover erased scope information by inserting subqueries when necessary.
1. The logical plan must be created using HiveQL query string
Query plans generated by composing arbitrary DataFrame API combinations are not supported yet. Operators within these query plans need to be rearranged into a canonical form that is more suitable for direct SQL generation. For example, the following query plan
```
Filter (a#1 < 10)
+- MetastoreRelation default, src, None
```
need to be canonicalized into the following form before SQL generation:
```
Project [a#1, b#2, c#3]
+- Filter (a#1 < 10)
+- MetastoreRelation default, src, None
```
Otherwise, the SQL generation process will have to handle a large number of special cases.
1. Only a fraction of expressions and basic logical plan operators are supported in this PR
Currently, 95.7% (1720 out of 1798) query plans in `HiveCompatibilitySuite` can be successfully converted to SQL query strings.
Known unsupported components are:
- Expressions
- Part of math expressions
- Part of string expressions (buggy?)
- Null expressions
- Calendar interval literal
- Part of date time expressions
- Complex type creators
- Special `NOT` expressions, e.g. `NOT LIKE` and `NOT IN`
- Logical plan operators/patterns
- Cube, rollup, and grouping set
- Script transformation
- Generator
- Distinct aggregation patterns that fit `DistinctAggregationRewriter` analysis rule
- Window functions
Support for window functions, generators, and cubes etc. will be added in follow-up PRs.
This PR leverages `HiveCompatibilitySuite` for testing SQL generation in a "round-trip" manner:
* For all select queries, we try to convert it back to SQL
* If the query plan is convertible, we parse the generated SQL into a new logical plan
* Run the new logical plan instead of the original one
If the query plan is inconvertible, the test case simply falls back to the original logic.
TODO
- [x] Fix failed test cases
- [x] Support for more basic expressions and logical plan operators (e.g. distinct aggregation etc.)
- [x] Comments and documentation
Author: Cheng Lian <lian@databricks.com>
Closes#10541 from liancheng/sql-generation.
This PR adds bucket write support to Spark SQL. User can specify bucketing columns, numBuckets and sorting columns with or without partition columns. For example:
```
df.write.partitionBy("year").bucketBy(8, "country").sortBy("amount").saveAsTable("sales")
```
When bucketing is used, we will calculate bucket id for each record, and group the records by bucket id. For each group, we will create a file with bucket id in its name, and write data into it. For each bucket file, if sorting columns are specified, the data will be sorted before write.
Note that there may be multiply files for one bucket, as the data is distributed.
Currently we store the bucket metadata at hive metastore in a non-hive-compatible way. We use different bucketing hash function compared to hive, so we can't be compatible anyway.
Limitations:
* Can't write bucketed data without hive metastore.
* Can't insert bucketed data into existing hive tables.
Author: Wenchen Fan <wenchen@databricks.com>
Closes#10498 from cloud-fan/bucket-write.
This PR moves a major part of the new SQL parser to Catalyst. This is a prelude to start using this parser for all of our SQL parsing. The following key changes have been made:
The ANTLR Parser & Supporting classes have been moved to the Catalyst project. They are now part of the ```org.apache.spark.sql.catalyst.parser``` package. These classes contained quite a bit of code that was originally from the Hive project, I have added aknowledgements whenever this applied. All Hive dependencies have been factored out. I have also taken this chance to clean-up the ```ASTNode``` class, and to improve the error handling.
The HiveQl object that provides the functionality to convert an AST into a LogicalPlan has been refactored into three different classes, one for every SQL sub-project:
- ```CatalystQl```: This implements Query and Expression parsing functionality.
- ```SparkQl```: This is a subclass of CatalystQL and provides SQL/Core only functionality such as Explain and Describe.
- ```HiveQl```: This is a subclass of ```SparkQl``` and this adds Hive-only functionality to the parser such as Analyze, Drop, Views, CTAS & Transforms. This class still depends on Hive.
cc rxin
Author: Herman van Hovell <hvanhovell@questtec.nl>
Closes#10583 from hvanhovell/SPARK-12575.
