Re: [android-developers] Re: SQLite concurrent access best practices
I believe you can provide the safe concurrency managment by using DB transactions. Since you don't care about sequence between separate activities you can run following snippet: try db.BeginTransaction db.RunCommand(insert or update etc.) db.CommitTransaction catch db.RollbackTransaction Evgeny On Sun, May 9, 2010 at 8:18 AM, Senthil ACS acs@gmail.com wrote: For insert() and update(), have it under synchronized blocks. On May 8, 5:40 pm, Thierry Legras tleg...@gmail.com wrote: Hi, I have an application with several tables, each being updated by AsyncTask fired by different Activities and used by UI with SimpleCursorAdapter. Though i am not developping a game, I would like to avoid to interrupt the user as mush as possible. Has SQLite is not multiaccess proof, what is the best way of handling such situation? - I consider adding lock from each DB open and to each close sequence but this seems quite subject to bugs - The solution i am using now is that each DB access (read/write) is done in UI thread (when AsyncTask completes, DB write is done typically in onPostExecute), but that means user is blocked for several seconds during the DB write. Is there any better solution for that? Should i use a ContentProvider? when i read Content providers store and retrieve data and make it accessible to all applications, this does not seems to be what i need. Any idea? -- Thierry. -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.comandroid-developers%2bunsubscr...@googlegroups.com For more options, visit this group athttp:// groups.google.com/group/android-developers?hl=en -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.comandroid-developers%2bunsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] Re: SQLite concurrent access best practices
Thank you both for your answers.
Are you sure using synchronized is enough inside the insert or update? I
also got exceptions in call to getReadableDatabase while another thread was
being writing so i don't think it would work. I am already using transaction
for DB write but it did not seem to make any changes.
The way i do each time i need to read/write/update DB is something like
that:
OnRead() {
db = new myDBHelperClass();
db.getReadableDatabase
db.query(...)
db.close()
}
OnWrite() {
db = new myDBHelperClass();
db.getWriteableDatabase
db.beginTransaction
db.insert(...)
db.endTransaction
}
I was rather thinking of using a synchronized in OnRead and OnWrite, but has
such methods exists in differents Activities and Task, i am pretty reluctant
to do that.
I also so design were DB is open in Activity onCreate and closed in
onDestroy, but i guess i will not work when a task also needs write in the
DB while the DB is open by the activity.
2010/5/9 Evgeny V evgen...@gmail.com
I believe you can provide the safe concurrency managment by using DB
transactions. Since you don't care about sequence between separate
activities you can run following snippet:
try
db.BeginTransaction
db.RunCommand(insert or update etc.)
db.CommitTransaction
catch
db.RollbackTransaction
Evgeny
On Sun, May 9, 2010 at 8:18 AM, Senthil ACS acs@gmail.com wrote:
For insert() and update(), have it under synchronized blocks.
On May 8, 5:40 pm, Thierry Legras tleg...@gmail.com wrote:
Hi,
I have an application with several tables, each being updated by
AsyncTask
fired by different Activities and used by UI with SimpleCursorAdapter.
Though i am not developping a game, I would like to avoid to interrupt
the
user as mush as possible.
Has SQLite is not multiaccess proof, what is the best way of handling
such
situation?
- I consider adding lock from each DB open and to each close sequence
but
this seems quite subject to bugs
- The solution i am using now is that each DB access (read/write) is
done in
UI thread (when AsyncTask completes, DB write is done typically in
onPostExecute), but that means user is blocked for several seconds
during
the DB write.
Is there any better solution for that? Should i use a ContentProvider?
when
i read Content providers store and retrieve data and make it accessible
to
all applications, this does not seems to be what i need. Any idea?
--
Thierry.
(snip)
--
Thierry.
--
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[android-developers] Re: SQLite concurrent access best practices
For insert() and update(), have it under synchronized blocks. On May 8, 5:40 pm, Thierry Legras tleg...@gmail.com wrote: Hi, I have an application with several tables, each being updated by AsyncTask fired by different Activities and used by UI with SimpleCursorAdapter. Though i am not developping a game, I would like to avoid to interrupt the user as mush as possible. Has SQLite is not multiaccess proof, what is the best way of handling such situation? - I consider adding lock from each DB open and to each close sequence but this seems quite subject to bugs - The solution i am using now is that each DB access (read/write) is done in UI thread (when AsyncTask completes, DB write is done typically in onPostExecute), but that means user is blocked for several seconds during the DB write. Is there any better solution for that? Should i use a ContentProvider? when i read Content providers store and retrieve data and make it accessible to all applications, this does not seems to be what i need. Any idea? -- Thierry. -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group athttp://groups.google.com/group/android-developers?hl=en -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
