Re: [sqlite] "Database is locked" error in PHP via PDO despite setting timeout

[Mark Robson]

On Monday 20 March 2006 11:47, [EMAIL PROTECTED] wrote:
> BTW: Lots of people have multiple processes writing to the same
> SQLite database without problems - the SQLite website is a good
> example.  I do not know what you are doing wrong to get the
> locking problems you are experiencing.

I don't know how they manage it (unless of course, many of their writes fail 
and the txns roll back, and they don't notice or care).

On Monday 20 March 2006 11:58, Roger wrote:
> I am developing a web based application in PHP/Sqlite and i am forever
> getting that error. What i normally do is a simple
>
> service httpd restart.

This is no good. I'm creating a daemon-based server application, which is 
carrying out autonomous tasks. It does not currently run under httpd, and I 
have no plans to make it do so.

I have several processes which are carrying out a fair amount of work inside a 
transaction - doing several writes, then doing some other time-consuming 
operations, then providing everything goes OK, committing these transactions.

This means that there are some relatively long-lived transactions (several 
seconds, anyway) in progress.

However, with proper locking this should NOT cause a problem - it should 
simply serialise the transactional operations (or so I thought).

As it is, I've actually tried to port this to MySQL (using Mysql5 and InnoDB), 
but I'm getting some problems there too - I think I'll have to review my use 
of transactions etc.

Regards
 Mark

[sqlite] "Database is locked" error in PHP via PDO despite setting timeout

[Mark Robson]

Hi all,

I'm using Sqlite3 from PHP via PDO.

My application was working fine as long as there was only one process 
accessing the database, then I ran two instances at once. Now one of the 
processes is getting 

"Error message: SQLSTATE[HY000]: General error: 5 database is locked"

when trying to execute a statement which modifies the database.

I understand that this is liable to happen, unless a timeout is set via 
sqlite3_busy_timeout().

I have set this timeout using the $db->setAttribute(PDO::ATTR_TIMEOUT, 5.0) 
however it's made absolutely no difference to the behaviour.

It's certainly not waiting 5 seconds before giving me this error, and it's 
happening with exactly the same frequency as before. It's as if it's being 
ignored.

I've stepped through PHP in the debugger (gdb) and it's definitely calling 
sqlite3_busy_timeout with the appropriate parameters (5000 ms).

What else can I do to prevent this?

If the answer is "nothing", I'm going straight over to MySQL :)

Mark