I'm getting a "SQL error: database is locked" when I have several shell scripts attempting to write to the same sqlite database. I understand why it's happening, but I wonder if there's a way I can prevent it from happening - is there a way to make sqlite wait until the file is no longer locked? I don't see it in the man page.

It should be known, I'm using the sqlite3 CLI from a shell script, so there are no API calls being made (I read on the sqlite website that there was an API option to cause it to wait if you're inserting from C).

Hi

You can set a timeout for this with the .timeout command before you do the SQL commands. For example:

.timeout 5000
select ...

Which means it should wait 5 seconds for a table to unlock before giving the error message.

Edit:
Your error message show the database is locked, not the table, so I'm not sure if it works. But I've written scripts where many processes access the same database, which work.

I found this page with info about it:
http://www.sqlite.org/lockingv3.html

If the functionality isn't there, maybe your scripts could use a while loop to check for the existence of a 'flag' file, wait until the db is free (sleep), then create the 'flag' file once there's a successful open.

@ Guttorm - thanks for the link. I hadn't seen that doc before. That said, it doesn't appear to cover running commands from the shell. If it does, I don't see where to set any of the settings to which it refers (admittedly, I only scanned the article).

@ kbp - I did essentially that - I try to write to the db & then check the exit code after the write. If it's 0, I keep going, if it's non-zero, I wait 0.1 seconds & try again for up to X number of times before failing.