db:progress_handler

Installs a progress callback function

Prototype

db:progress_handler(n,func,udata)

Description

This function installs a callback function func that is invoked periodically during long-running calls to db:exec() or stmt:step(). The progress callback is invoked once for every n internal operations, where n is the first argument to this function. udata is passed to the progress callback function each time it is invoked. If a call to db:exec() or stmt:step() results in fewer than n operations being executed, then the progress callback is never invoked. Only a single progress callback function may be registered for each opened database and a call to this function will overwrite any previously set callback function. To remove the progress callback altogether, pass nil as the second argument.

If the progress callback returns a result other than 0, then the current query is immediately terminated, any database changes are rolled back and the containing db:exec() or stmt:step() call returns sqlite3.INTERRUPT. This feature can be used to cancel long-running queries.

Lua functions

Topics