Android sqlite beginransaction takes too long

Question

I want to insert parsed data from json to db in batch mode. I use the method below to insert a package. The problem is that mDbWritable.beginTransaction (); takes too long to complete. Usually like 6 seconds! I do not know where the problem is. Some thoughts, what can cause such a long execution time? Thank you very much.

@Override public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations) throws OperationApplicationException { long start = System.currentTimeMillis(); mDbWritable.beginTransaction(); long time = System.currentTimeMillis() - start; Alog.i(TAG, "Time applyBatch beginTransaction: " + time); final int numOperations = operations.size(); final ContentProviderResult[] results = new ContentProviderResult[numOperations]; try { for (int i = 0; i < numOperations; i++) { results[i] = operations.get(i).apply(this, results, i); } mDbWritable.setTransactionSuccessful(); } finally { mDbWritable.endTransaction(); } return results; } 

Example from magazines:

 11-16 15:14:53.726: I/ApiProvider(21442): Time applyBatch beginTransaction: 6025 11-16 15:15:00.713: I/ApiProvider(21442): Time applyBatch beginTransaction: 4940 11-16 15:15:17.819: I/ApiProvider(21442): Time applyBatch beginTransaction: 8651 11-16 15:15:45.346: I/ApiProvider(21442): Time applyBatch beginTransaction: 12672 11-16 15:16:16.807: I/ApiProvider(21442): Time applyBatch beginTransaction: 12411 11-16 15:16:45.685: I/ApiProvider(21442): Time applyBatch beginTransaction: 12247 11-16 15:17:01.500: I/ApiProvider(21442): Time applyBatch beginTransaction: 12788 

EDIT: I use a batch loop when parsing json. for example for each item in json-parse and apply the package. The package contains insert, update, delete operations.

Here is the code as I repeat and call applyBatch

 Cursor starredChannelsCursor = mContentResolver.query(ApiContract.Channels.CONTENT_URI, new String[] {BaseColumns._ID, ChannelsTable.ID, ChannelsTable.SLUG }, ChannelsTable.IS_STARRED + "=?",new String[] { "1" }, null); String userName = mSettings.getUserName(); if (starredChannelsCursor != null && starredChannelsCursor.moveToFirst()) { while (!starredChannelsCursor.isAfterLast()) { String channelSlug = starredChannelsCursor.getString(2); ChannelHandler channelHandler = new ChannelHandler(this); URI channelApiUri = Constants.getChannelApiURI(channelSlug,userName); //execute update make applybatch call executeUpdate(channelApiUri, channelHandler); starredChannelsCursor.moveToNext(); } } if (starredChannelsCursor != null) { starredChannelsCursor.close(); } /** * Make call to Uri, parse response and apply batch operations to * contentResolver * * @param apiUri * @param handler * - handles parsing */ private boolean executeUpdate(URI apiUri, AbstractJSONHandler handler) { ApiResponse apiResponse = mHttpHelper.doHttpCall(apiUri); ArrayList<ContentProviderOperation> batch = new ArrayList<ContentProviderOperation>(); if (apiResponse != null) { batch = handler.parse(apiResponse); Alog.v(TAG, "update user data from " + apiUri); } if (batch.size() > 0) { try { mContentResolver.applyBatch(ApiContract.CONTENT_AUTHORITY, batch); } catch (Exception e) { Alog.v(TAG, "Error: " + e.getMessage()); } } return true; } 

Answer 1

The only problem that seems possible is that different threads acquire the same lock when calling beginTransaction() and the waste time just waits for other threads to release the lock. Look at your code and see how you control the threads and from which threads you call the applyBatch(..) method.

You may also find it useful to look at the hierarchy of the beginTransaction() calls in the SQLiteDatabase class.