Teg <[EMAIL PROTECTED]> wrote: > Hello drh, > > Could you perhaps give us the rational for using TLS? How is it that > TLS is needed on cases where you run out of memory?
It makes the code smaller and faster to set a flag when malloc fails, rather than trying to test for the failure all the way back up the stack. The flag used to be a global variable. But that was causing problems for embedded device manufacturers. Specifically, embedded devices run out of memory quite often - a malloc() failure is routine. It is not acceptable to shut down the whole process just because malloc failed. But if the failure flag is in a global variable, there is no way to know which thread took the failure and hence no way to recover gracefully. Everything has to be stopped and restarted. By moving the malloc failure flag into TLS, we can recover gracefully from OOM without impacting other threads at all. TLS is also used to support new features of 3.3.0: Share caches and memory management. Both are off by default. But if you want to use them you will need TLS. -- D. Richard Hipp <[EMAIL PROTECTED]>
