pool for the database, null when closed. // The pool itself is thread-safe, but the reference to it can only be acquired // when the lock is held. // INVARIANT: Guarded by mLock. private SQLiteConnectionPool mConnectionPoolLocked; }
null, null); if (!value.equalsIgnoreCase(newValue)) { try { String result = executeForString("PRAGMA journal_mode=" + newValue, null, null); if (result.equalsIgnoreCase(newValue)) { return; } // PRAGMA journal_mode silently fails and returns the original journal // mode in some cases if the journal mode could not be changed. } catch (SQLiteDatabaseLockedException ex) { // This error (SQLITE_BUSY) occurs if one connection has the database // open in WAL mode and another tries to change it to non-WAL. } ... }
refresh only if we are NOT in a transaction. Otherwise, wait for the last // endTransaction call to do it. mInvalidationTracker.refreshVersionsAsync(); } }
@JvmStatic suspend fun <R> execute( db: RoomDatabase, inTransaction: Boolean, callable: Callable<R> ): R { if (db.isOpen && db.inTransaction()) { return callable.call() } // Use the transaction dispatcher if we are on a transaction coroutine, otherwise // use the database dispatchers. val context = coroutineContext[TransactionElement]?.transactionDispatcher ?: if (inTransaction) db.transactionDispatcher else db.queryDispatcher return withContext(context) { callable.call() } } } }
public void beginTransaction() { assertNotMainThread(); SupportSQLiteDatabase database = mOpenHelper.getWritableDatabase(); mInvalidationTracker.syncTriggers(database); database.beginTransaction(); } /** * Wrapper for {@link SupportSQLiteDatabase#endTransaction()}. * * @deprecated Use {@link #runInTransaction(Runnable)} */ @Deprecated public void endTransaction() { mOpenHelper.getWritableDatabase().endTransaction(); if (!inTransaction()) { // enqueue refresh only if we are NOT in a transaction. Otherwise, wait for the last // endTransaction call to do it. mInvalidationTracker.refreshVersionsAsync(); } } }
that the * window will contain the requested row and a useful range of rows * around it. * * When the data set is too large to fit in a cursor window, seeking the * cursor can become a very expensive operation since we have to run the * query again when we move outside the bounds of the current window. * * We try to choose a start position for the cursor window such that * 1/3 of the window's capacity is used to hold rows before the requested * position and 2/3 of the window's capacity is used to hold rows after the * requested position. * * @param cursorPosition The row index of the row we want to get. * @param cursorWindowCapacity The estimated number of rows that can fit in * a cursor window, or 0 if unknown. * @return The recommended start position, always less than or equal to * the requested row. * @hide */ public static int cursorPickFillWindowStartPosition( int cursorPosition, int cursorWindowCapacity) { return Math.max(cursorPosition - cursorWindowCapacity / 3, 0); }