b8d3da16b1
### What changes were proposed in this pull request?
Currently, AQE uses a very tricky way to trigger and wait for the subqueries:
1. submitting stage calls `QueryStageExec.materialize`
2. `QueryStageExec.materialize` calls `executeQuery`
3. `executeQuery` does some preparation works, which goes to `QueryStageExec.doPrepare`
4. `QueryStageExec.doPrepare` calls `prepare` of shuffle/broadcast, which triggers all the subqueries in this stage
5. `executeQuery` then calls `waitForSubqueries`, which does nothing because `QueryStageExec` itself has no subqueries
6. then we submit the shuffle/broadcast job, without waiting for subqueries
7. for `ShuffleExchangeExec.mapOutputStatisticsFuture`, it calls `child.execute`, which calls `executeQuery` and wait for subqueries in the query tree of `child`
8. The only missing case is: `ShuffleExchangeExec` itself may contain subqueries(repartition expression) and AQE doesn't wait for it.
A simple fix would be overwriting `waitForSubqueries` in `QueryStageExec`, and forward the request to shuffle/broadcast, but this PR proposes a different and probably cleaner way: we follow `execute`/`doExecute` in `SparkPlan`, and add similar APIs in the AQE version of "execute", which gets a future from shuffle/broadcast.
### Why are the changes needed?
bug fix
### Does this PR introduce _any_ user-facing change?
a query fails without the fix and can run now
### How was this patch tested?
new test
Closes #33058 from cloud-fan/aqe.
Authored-by: Wenchen Fan <wenchen@databricks.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
(cherry picked from commit
|
||
---|---|---|
.. | ||
catalyst | ||
core | ||
hive | ||
hive-thriftserver | ||
create-docs.sh | ||
gen-sql-api-docs.py | ||
gen-sql-config-docs.py | ||
gen-sql-functions-docs.py | ||
mkdocs.yml | ||
README.md |
Spark SQL
This module provides support for executing relational queries expressed in either SQL or the DataFrame/Dataset API.
Spark SQL is broken up into four subprojects:
- Catalyst (sql/catalyst) - An implementation-agnostic framework for manipulating trees of relational operators and expressions.
- Execution (sql/core) - A query planner / execution engine for translating Catalyst's logical query plans into Spark RDDs. This component also includes a new public interface, SQLContext, that allows users to execute SQL or LINQ statements against existing RDDs and Parquet files.
- Hive Support (sql/hive) - Includes extensions that allow users to write queries using a subset of HiveQL and access data from a Hive Metastore using Hive SerDes. There are also wrappers that allow users to run queries that include Hive UDFs, UDAFs, and UDTFs.
- HiveServer and CLI support (sql/hive-thriftserver) - Includes support for the SQL CLI (bin/spark-sql) and a HiveServer2 (for JDBC/ODBC) compatible server.
Running ./sql/create-docs.sh
generates SQL documentation for built-in functions under sql/site
, and SQL configuration documentation that gets included as part of configuration.md
in the main docs
directory.