The SQLiteDatabase constructor is inaccessible so it is not
possible for applications to subclass it. To remove all possible
remaining temptation to do so, make the class final.
Change-Id: I4148e9b06f0661ec22aab8e45afde38498d2375a
This change leaves the sync mode at FULL for both WAL and non-WAL
but makes it easy to change it for one but not the other.
To reduce the number of synchronous writes, it might make sense to
change the sync mode for non-WAL to NORMAL instead of FULL which
should be just as safe.
On the other hand, the sync mode for WAL should probably remain FULL
because there may be an impact on transaction durability otherwise.
Initial experiments show that there might not be a significant
performance benefit to using NORMAL, but we may revisit this later.
Change-Id: Ifcd55bedcfefa6600974c2295ca5d4163b408cbf
Add SQLiteDatabase.deleteDatabase to delete a database and all
of its auxiliary files.
This method is also used by Context.deleteDatabase and resolves issues
where auxiliary files would get left behind.
Bug: 5972489
Change-Id: I3633b9b4978972a1d240ac0a9861420ecf989149
Moved more configuration into config.xml so we can tweak settings
like the default journal mode, WAL auto-checkpoint interval and
so on.
This change itself should not introduce any functional differences.
Change-Id: Id6c95fa25b116ce47e8ae49cd8a80d52b1c0dd80
Combine the code for opening readable and writable databases.
This improves the handling of the case where a database cannot
be opened because it cannot be upgraded. Previously we would
open the database twice: first read-write, then read-only, each
time failing due to the version check. Now only open it once.
Removed the goofy locking logic related to upgrading a read-only
database to read-write. We now do it in place by reopening the
necessary connections in the connection pool.
Change-Id: I6deca3fb90e43f4ccb944d4715307fd6fc3e1383
Added new API to enable cancelation of SQLite and content provider
queries by means of a CancelationSignal object. The application
creates a CancelationSignal object and passes it as an argument
to the query. The cancelation signal can then be used to cancel
the query while it is executing.
If the cancelation signal is raised before the query is executed,
then it is immediately terminated.
Change-Id: If2c76e9a7e56ea5e98768b6d4f225f0a1ca61c61
Added a new method ContentObserver.onChange(boolean, Uri) that
receives the changed content Uri. This can help applications make
better decisions about how to interpret a change notification.
Change-Id: I8e35378b6485fe22c5bc240ba07557d269af0836
Improved the documentation a little bit.
Fixed a bug in ContentService wherein if a ContentObserver was
passed as an argument and its deliverSelfNotifications() method
returned true, then notifyChange would tell all observers that
the change was a self-change even though it was only a self-change
from the perspective of the provided observer.
Deprecated ContentObservable.notifyChange since it is never
used and in general it shouldn't be because we want the notification
to be posted to the handler.
Change-Id: Idde49eb40777e011a068f2adae8a32f779dfb923
This ensures that the SQLite library is always correctly configured
and initialized before other framework or application code has
a chance to use it. This is important because initialization has
to happen at most once so we need to get it right and prevent races.
This change makes it possible to omit the SQLite auto-initialization
workaround from the SQLite library, potentially saving a few cycles
here and there.
Change-Id: Ifbed8685ee44aa1e9c0b391e233b0257fa738e4f
This error code was introduced at some point to help track when
a database could not be closed because a statement was not finalized.
Now that the DB wrappers have been rewritten, it is technically no longer
poossible for this to happen, so we can remove this.
Change-Id: Ibbd55debbf390af436d6533aebff9726b1ff29e7
Deleted a bunch of dead / useless code.
Raised number of logged operations in dumpsys dbinfo to 20.
Change-Id: I88344ff57a978f200c1f0172141d91e430caa1a9
Modified SQLiteConnection and SQLiteSession to support
reentrant execution of SQLite operations, as might occur
when a custom function is invoked by a trigger.
Bug: 5884809
Change-Id: I253d828b2801bd06b1bbda7caa7da3f040a642bb
The main theme of this change is encapsulation. This change
preserves all existing functionality but the implementation
is now much cleaner.
Instead of a "database lock", access to the database is treated
as a resource acquisition problem. If a thread's owns a database
connection, then it can access the database; otherwise, it must
acquire a database connection first, and potentially wait for other
threads to give up theirs. The SQLiteConnectionPool encapsulates
the details of how connections are created, configured, acquired,
released and disposed.
One new feature is that SQLiteConnectionPool can make scheduling
decisions about which thread should next acquire a database
connection when there is contention among threads. The factors
considered include wait queue ordering (fairness among peers),
whether the connection is needed for an interactive operation
(unfairness on behalf of the UI), and whether the primary connection
is needed or if any old connection will do. Thus one goal of the
new SQLiteConnectionPool is to improve the utilization of
database connections.
To emulate some quirks of the old "database lock," we introduce
the concept of the primary database connection. The primary
database connection is the one that is typically used to perform
write operations to the database. When a thread holds the primary
database connection, it effectively prevents other threads from
modifying the database (although they can still read). What's
more, those threads will block when they try to acquire the primary
connection, which provides the same kind of mutual exclusion
features that the old "database lock" had. (In truth, we
probably don't need to be requiring use of the primary database
connection in as many places as we do now, but we can seek to refine
that behavior in future patches.)
Another significant change is that native sqlite3_stmt objects
(prepared statements) are fully encapsulated by the SQLiteConnection
object that owns them. This ensures that the connection can
finalize (destroy) all extant statements that belong to a database
connection when the connection is closed. (In the original code,
this was very complicated because the sqlite3_stmt objects were
managed by SQLiteCompiledSql objects which had different lifetime
from the original SQLiteDatabase that created them. Worse, the
SQLiteCompiledSql finalizer method couldn't actually destroy the
sqlite3_stmt objects because it ran on the finalizer thread and
therefore could not guarantee that it could acquire the database
lock in order to do the work. This resulted in some rather
tortured logic involving a list of pending finalizable statements
and a high change of deadlocks or leaks.)
Because sqlite3_stmt objects never escape the confines of the
SQLiteConnection that owns them, we can also greatly simplify
the design of the SQLiteProgram, SQLiteQuery and SQLiteStatement
objects. They no longer have to wrangle a native sqlite3_stmt
object pointer and manage its lifecycle. So now all they do
is hold bind arguments and provide a fancy API.
All of the JNI glue related to managing database connections
and performing transactions is now bound to SQLiteConnection
(rather than being scattered everywhere). This makes sense because
SQLiteConnection owns the native sqlite3 object, so it is the
only class in the system that can interact with the native
SQLite database directly. Encapsulation for the win.
One particularly tricky part of this change is managing the
ownership of SQLiteConnection objects. At any given time,
a SQLiteConnection is either owned by a SQLiteConnectionPool
or by a SQLiteSession. SQLiteConnections should never be leaked,
but we handle that case too (and yell about it with CloseGuard).
A SQLiteSession object is responsible for acquiring and releasing
a SQLiteConnection object on behalf of a single thread as needed.
For example, the session acquires a connection when a transaction
begins and releases it when finished. If the session cannot
acquire a connection immediately, then the requested operation
blocks until a connection becomes available.
SQLiteSessions are thread-local. A SQLiteDatabase assigns a
distinct session to each thread that performs database operations.
This is very very important. First, it prevents two threads
from trying to use the same SQLiteConnection at the same time
(because two threads can't share the same session).
Second, it prevents a single thread from trying to acquire two
SQLiteConnections simultaneously from the same database (because
a single thread can't have two sessions for the same database which,
in addition to being greedy, could result in a deadlock).
There is strict layering between the various database objects,
objects at lower layers are not aware of objects at higher layers.
Moreover, objects at higher layers generally own objects at lower
layers and are responsible for ensuring they are properly disposed
when no longer needed (good for the environment).
API layer: SQLiteDatabase, SQLiteProgram, SQLiteQuery, SQLiteStatement.
Session layer: SQLiteSession.
Connection layer: SQLiteConnectionPool, SQLiteConnection.
Native layer: JNI glue.
By avoiding cyclic dependencies between layers, we make the
architecture much more intelligible, maintainable and robust.
Finally, this change adds a great deal of new debugging information.
It is now possible to view a list of the most recent database
operations including how long they took to run using
"adb shell dumpsys dbinfo". (Because most of the interesting
work happens in SQLiteConnection, it is easy to add debugging
instrumentation to track all database operations in one place.)
Change-Id: Iffb4ce72d8bcf20b4e087d911da6aa84d2f15297
For non-localized strings like the keywords in SQL statements, we shouldn't use
locale-specific case transformations.
(Cherry pick of 03f8f84c345e7c861a6de889d434b9d82cf04c8d.)
Bug: 4284951
Change-Id: Ib5180daf7892af7b645c906fdfeacf9da87bd667
We can do this because the classes already cannot be subclassed
by applications due to the fact they only have package private
constructors.
One very nice consequence of this observation is that we can hide or
delete several @deprecated protected members which are effectively
inaccessible because applications cannot create subclasses!
Change-Id: I2d3a0d2ad72b9289ebcdf907e4e4e6caf27f9076
On user-debug and eng builds, you can set the
"db.log.slow_query_threshold" system property to queries that
take longer than the specified number of milliseconds.
Set it to 0 to log all queries.
This property has been around for a while but it was implemented
poorly. In particular, it *changed* the behavior of the query
by calling getCount() while holding the Db connection.
In normal operation, the query will not actually run until later.
By putting the timing logic into fillWindow() instead, we ensure
that we only measure queries that actually ran. We also capture
cases where the cursor window gets filled multiple times.
Bug: 5520301
Change-Id: I174f5e1ea15831a1d22a36e9a804d7755f230b38
Bug: 5520301
When an application requests a row from a SQLiteCursor that
is not in the window, instead of filling from the requested
row position onwards, fill from a little bit ahead of the
requested row position.
This fixes a problem with applications that seek backwards
in large cursor windows. Previously the application could
end up refilling the window every time it moved back
one position.
We try to fill about 1/3 before the requested position and
2/3 after which substantially improves scrolling responsiveness
when the list is bound to a data set that does not fit
entirely within one cursor window.
Change-Id: I168ff1d3aed1a41ac96267be34a026c108590e52
When the StrictMode VM flag is changed mid-lifecycle, pass along at
least a basic trace.
Bug: 5516561
Change-Id: I6c922ba20f34349c35624cfc04d1c71ee56ad6ef
Bug: 5220669
The CrossProcessCursorWrapper is a useful building block
for wrapping cursors that will be sent to processes remotely.
It can also transform normal Cursors into CrossProcessCursors
transparently.
The new class fixes common performance problems and bugs
that applications have encountered when implementing
ContentProviders.
Change-Id: Icc59fec10add3f7d8cfbd0495447860c1872c752
Use the CrossProcessCursor interface in the way it was intended
without introducing special cases for AbstractWindowedCursor.
This is possible now that we do not distinguish between local-only
and remotable CursorWindows so we don't need to provide a window
to the AbstractWindowedCursor for it to fill; it can provide one
for itself if it wants one.
This logic makes it possible to create CrossProcessCursor
implementations that perform just as well as AbstractWindowedCursors.
Change-Id: I764b25ee6311d28c50d1930705346b265faec86a
Bug: 5218310
This change fixes problems calling the default fillWindow
on Cursors that contain BLOBs. It should also be more efficient
by avoiding redundant string conversions for numeric datatypes.
Change-Id: Ied515bf6299bc8d3c14e76055d85fd35e7c05952
There is no difference and has never really been a difference
between local-only and remotable CursorWindows. By removing the
distinction officially in the API, we will make it easier to
implement CrossProcessCursor correctly. CrossProcessCursor
is problematic currently because it's not clear whether a call
to getWindow() will return a local-only window or a remotable window.
As a result, the bulk cursor adaptor has special case handling
for AbstractWindowedCursors vs. ordinary CrossProcessCursors
so that it can set a remotable window before the cursor fills it.
All these problems go away if we just forget about local-only
windows being special in any way.
Change-Id: Ie59f517968e33d0ecb239c3c4f60206495e8f376
Bug: 5332296
The memory dealer introduces additional delays for reclaiming
the memory owned by CursorWindows because the Binder object must
be finalized. Using ashmem instead gives CursorWindow more
direct control over the lifetime of the shared memory region.
The provider now allocates the CursorWindows and returns them
to clients with a read-only protection bit set on the ashmem
region.
Improved the encapsulation of CursorWindow. Callers shouldn't
need to care about details like how string fields are allocated.
Removed the compile-time configuration of string and numeric
storage modes to remove some dead weight.
Change-Id: I07c2bc2a9c573d7e435dcaecd269d25ea9807acd
Bug: 5332296
Ensure that there is always an owner for each CursorWindow
and that references to each window are acquired/released
appropriately at all times.
Added synchronization to CursorToBulkCursorAdaptor to
prevent the underlying Cursor and CursorWindow from being
remotely accessed in ways that might violate invariants,
resulting in leaks or other problems.
Ensured that CursorToBulkCursorAdaptor promptly releases
its references to the Cursor and CursorWindow when closed
so they don't stick around longer than they should, even
if the remote end hangs onto the IBulkCursor for some reason.
CursorWindow respects Parcelable.FLAG_WRITE_RETURN_VALUE
as an indication that one reference to the CursorWindow is
being released. Correspondingly, CursorToBulkCursorAdaptor
acquires a reference to the CursorWindow before returning
it to the caller. This change also prevents races from
resulting in the transfer of an invalid CursorWindow over
the wire.
Ensured that BulkCursorToCursorAdaptor promptly releases
its reference to the IBulkCursor when closed and throws
on attempts to access the cursor while closed.
Modified ContentProviderNative to handle both parts of
the wrapping and unwrapping of Cursors into IBulkCursors.
This makes it a lot easier to ensure that the right
things happen on both ends. Also, it turns out that
the only caller of IContentProvider.bulkQuery was
ContentProviderNative itself so there was no need
to support bulkQuery on ContentProviderProxy and it was
just getting in the way.
Implement CloseGuard on CursorWindow.
Change-Id: Ib3c8305d3cc62322f38a06698d404a2989bb6ef9
Bug: 5332296
We can't replace these with AIDL generated proxies just yet, but
at least we can make them a little more conformant.
Change-Id: I1814f76d0f9c5e44a7fd85a12b2e3c2b7e3c9daa
