Re: [sqlite] "Database is locked" error in PHP via PDO despite setting timeout
If you want to use a lightweight DB like Sqlite and you are setting up your own daemon and server situation then you can place the DB synchronization function in the daemon around the Sqlite so that its action is single streamed. In a similar situation we have installations which manage many hundreds of simultaneous users. If you don't want to do that, use a DBMS like PostgreSQL which manages it all for you by having a DB server, not linking the DB function into the application. Mark Robson wrote: 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
Re: [sqlite] "Database is locked" error in PHP via PDO despite setting timeout
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
Re: [sqlite] "Database is locked" error in PHP via PDO despite setting timeout
What i normally do in this scenario is just a simple httpd service restart. That normally does the trick because i am building an application also with PHP/Sqlite. On Mon, 2006-03-20 at 06:47 -0500, [EMAIL PROTECTED] wrote: > Mark Robson <[EMAIL PROTECTED]> wrote: > > > > If the answer is "nothing", I'm going straight over to MySQL :) > > > > The advantages of SQLite are that there are no administrative > hassles - there is nothing to set up or configure and the > database is contained in a single disk file that you can copy > to a flash drive or something. Client/server database engines > like MySQL normally default to READ COMMITTED isolation, which > means you never have database locking problems, but at the expense > of considerable setup and configuration complexity. > > It sounds to me like you are more interested in READ COMMITTED > isolation and do not mind the added complexity, in which case > you should be using a client/server database, such as MySQL. > > 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. > > -- > D. Richard Hipp <[EMAIL PROTECTED]> >
Re: [sqlite] "Database is locked" error in PHP via PDO despite setting timeout
Mark Robson <[EMAIL PROTECTED]> wrote: > > If the answer is "nothing", I'm going straight over to MySQL :) > The advantages of SQLite are that there are no administrative hassles - there is nothing to set up or configure and the database is contained in a single disk file that you can copy to a flash drive or something. Client/server database engines like MySQL normally default to READ COMMITTED isolation, which means you never have database locking problems, but at the expense of considerable setup and configuration complexity. It sounds to me like you are more interested in READ COMMITTED isolation and do not mind the added complexity, in which case you should be using a client/server database, such as MySQL. 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. -- D. Richard Hipp <[EMAIL PROTECTED]>
[sqlite] "Database is locked" error in PHP via PDO despite setting timeout
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
