Transaction deadlock when combining suspend DAO functions and beginTransaction() [120854786]

Fixed

Bug

Status Update

No update yet.

Description

da...@google.com

created issue #1

Dec 11, 2018 08:45PM

A query performed in a suspend function might deadlock if the suspend function invocation was done after a transaction was started. For example:

withContext(Dispatchers.Default) {
db.beginTransaction()
db.insert(data) // DAO suspend function
db.update(anotherData) // DAO suspend function
db.setTransactionSuccessful()
db.endTransaction()
}

This can deadlock because transaction are exclusive and are ThreadLocal, meaning once a transaction is started in a thread form the default dispatcher, another coroutine dispatcher thread will get blocked even if we are within the same coroutine.

Comments

ia...@gmail.com <ia...@gmail.com> #2Dec 11, 2018 09:15PM

What version of Activity are you using? Upgrading your Activity dependency 1.7.2 which also depends on Lifecycle 2.6.1 should resolve this.

yb...@google.com <yb...@google.com> Dec 13, 2018 06:15PM

Reassigned to yb...@google.com.

yb...@google.com <yb...@google.com> #3Dec 14, 2018 08:21PM

Reassigned to da...@google.com.

Thanks. I stumbled upon

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:activity/activity/src/main/java/androidx/activity/ComponentDialog.kt;bpv=1;bpt=0
And see it was fixed in commit 602bac6c67b589d11f8f4d1441a4aec4dca0ee49.
Ill wait to upgrade until after that commit is in the stable release.

yb...@google.com <yb...@google.com> #4Dec 14, 2018 08:21PM

It is stable in the releases I referenced above.

ia...@gmail.com <ia...@gmail.com> #5Dec 14, 2018 08:38PM

Fragment 1.6.1 will update the dependency of Activity to 1.7.2 so you'll get this improvement by default. As mentioned above, you can add a dependency on Activity 1.7.2 right now to fix the issue as a workaround until that release comes out.

yb...@google.com <yb...@google.com> #6Dec 14, 2018 10:34PM

yea the issue w/ suspending room version is that we need to make sure we can carry over the transaction information so that it can go to the right thread and only it (not some other parallel task).
This is why we need a proper transaction abstraction to safely do these jumps (or at least thats what i thnk we'll need, maybe not)

ap...@google.com <ap...@google.com> #7Feb 26, 2019 11:06PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit 69961b4ef143d82f50c3a7fd3969826d51a0ee25
Author: Daniel Santiago Rivera <danysantiago@google.com>
Date: Thu Jan 31 12:57:58 2019

Room Suspending Transaction

Create an API for performing database transaction with coroutines. When
starting a transaction coroutine a thread of the database query executor
is hold for performing all database operations within the coroutine. It
is recommended that all DAO functions invoked are also suspend
functions. In the case they are blocking DAO methods, then invoking
those on a different context other than the transaction context will
throw an exception, preventing possible deadlocks.

Bug: 120854786
Test: ./gradlew room:room-compiler:test
room:integration-tests:room-testapp-kotlin:cC
room:integration-tests:room-testapp:cC

Change-Id: I30f76db29a3882968f43e1dd1c1038b5afd7f299

M room/compiler/src/main/kotlin/androidx/room/solver/prepared/binder/InstantPreparedQueryResultBinder.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/InstantQueryResultBinder.kt
M room/compiler/src/main/kotlin/androidx/room/solver/shortcut/binder/InstantDeleteOrUpdateMethodBinder.kt
M room/compiler/src/main/kotlin/androidx/room/solver/shortcut/binder/InstantInsertMethodBinder.kt
M room/compiler/src/test/data/daoWriter/output/ComplexDao.java
M room/compiler/src/test/data/daoWriter/output/DeletionDao.java
M room/compiler/src/test/data/daoWriter/output/UpdateDao.java
M room/compiler/src/test/data/daoWriter/output/WriterDao.java
M room/coroutines/api/2.1.0-alpha05.txt
M room/coroutines/api/current.txt
M room/coroutines/build.gradle
M room/coroutines/src/main/java/androidx/room/CoroutinesRoom.kt
A room/coroutines/src/main/java/androidx/room/RoomDatabase.kt
M room/integration-tests/kotlintestapp/build.gradle
M room/integration-tests/kotlintestapp/src/androidTest/java/androidx/room/integration/kotlintestapp/test/SuspendingQueryTest.kt
M room/runtime/api/restricted_2.1.0-alpha05.txt
M room/runtime/api/restricted_current.txt
M room/runtime/src/main/java/androidx/room/RoomDatabase.java

https://android-review.googlesource.com/891674

https://goto.google.com/android-sha1/69961b4ef143d82f50c3a7fd3969826d51a0ee25

ap...@google.com <ap...@google.com> #8Feb 26, 2019 11:08PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit f0f9ed8db13fbeb028391af00b626e19a0f2746e
Author: Daniel Santiago Rivera <danysantiago@google.com>
Date: Mon Feb 11 14:35:55 2019

Deprecate RoomDatabase transaction methods.

Deprecate beginTransaction, setTransactionSuccessful and endTransaction,
in favor of runInTransaction. Deprecating these methods discourage
users from using them within coroutines.

Bug: 120854786
Test: ./gradlew room:room-compiler:test
room:integration-tests:room-testapp-kotlin:cC
room:integration-tests:room-testapp:cC

Change-Id: Idc1bb04555fdba78eb1142b3ba461b87e6b06a69

M room/compiler/src/main/kotlin/androidx/room/writer/ClassWriter.kt
M room/compiler/src/test/data/daoWriter/output/ComplexDao.java
M room/compiler/src/test/data/daoWriter/output/DeletionDao.java
M room/compiler/src/test/data/daoWriter/output/UpdateDao.java
M room/compiler/src/test/data/daoWriter/output/WriterDao.java
M room/compiler/src/test/data/databasewriter/output/ComplexDatabase.java
M room/compiler/src/test/kotlin/androidx/room/writer/EntityCursorConverterWriterTest.kt
M room/coroutines/src/main/java/androidx/room/RoomDatabase.kt
M room/integration-tests/kotlintestapp/src/androidTest/java/androidx/room/integration/kotlintestapp/migration/MigrationKotlinTest.kt
M room/integration-tests/kotlintestapp/src/androidTest/java/androidx/room/integration/kotlintestapp/test/SuspendingQueryTest.kt
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/migration/FtsMigrationTest.java
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/migration/MigrationTest.java
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/paging/DataSourceFactoryTest.java
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/test/ForeignKeyTest.java
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/test/MultiInstanceInvalidationTest.java
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/test/QueryTransactionTest.java
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/test/RxJava2Test.java
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/test/RxJava2WithInstantTaskExecutorTest.java
M room/integration-tests/testapp/src/androidTest/java/androidx/room/integration/testapp/test/WriteAheadLoggingTest.java
M room/runtime/api/2.1.0-alpha05.txt
M room/runtime/api/current.txt
M room/runtime/src/main/java/androidx/room/RoomDatabase.java
M room/runtime/src/main/java/androidx/room/paging/LimitOffsetDataSource.java

https://android-review.googlesource.com/900916

https://goto.google.com/android-sha1/f0f9ed8db13fbeb028391af00b626e19a0f2746e

da...@google.com <da...@google.com> Feb 26, 2019 11:11PM

Marked as fixed.