So given the example below from the book, I would add all the controller functions that does database read to read_only_actions list? I would have to continuously maintain this list as my application grows. Is this the right approach?
if request.function in read_only_actions: db = DAL(sample(['mysql://...1','mysql://...2','mysql://...3'], 3)) elif request.action in read_only_actions: db = DAL(shuffle(['mysql://...1','mysql://...2','mysql://...3'])) else: db = DAL(sample(['mysql://...3','mysql://...4','mysql://...5'], 3)) where 1,2,3 are slaves and 3,4,5 are masters. On Jan 6, 2018 3:54 AM, "Dave S" <snidely....@gmail.com> wrote: On Friday, January 5, 2018 at 7:50:28 PM UTC-8, CDA wrote: > > How does web2py select a database to connect to based on the http request > content? Is it feasible to connect to different databases depending on > whether it is a read request or a write request? Can you provide example on > how to do this? > > I would expect that the http request wouldn't directly select a database. Instead, your controller would know if a select() was being done to satisfy the request (typical for HTTP GET, but often needed for other reasons), or an insert or update (often an HTTP POST or HTTP PUT), or a delete (such as for an HTTP DELETE). But it's your controller that decides what type of DB operation is required. AIUI. /dps > On Fri, Jan 5, 2018 at 6:35 PM, Anthony <abas...@gmail.com> wrote: > >> Do you have doubts about whether it would work? Seems fairly >> straightforward. >> >> >> On Friday, January 5, 2018 at 3:59:29 PM UTC-5, CDA wrote: >>> >>> >>> Below is an excerpt about horizontal scaling from Chapter 13 in the >>> book. Has any one successfully implemented this using web2py? >>> >>> It is also possible to connect to different databases depending on the >>> requested action or controller. In a master-slave database configuration, >>> *some* *action performs only a read* and *some performs both read/write*. >>> The former can safely connect to a slave db server, while the latter should >>> connect to a master. So you can do: >>> >>> >>> 1 >>> 2 >>> 3 >>> 4 >>> 5 >>> 6 >>> >>> if request.function in read_only_actions: >>> db = DAL(sample(['mysql://...1','mysql://...2','mysql://...3'], 3))elif >>> request.action in read_only_actions: >>> db = DAL(shuffle(['mysql://...1','mysql://...2','mysql://...3']))else: >>> db = DAL(sample(['mysql://...3','mysql://...4','mysql://...5'], 3)) >>> >>> >>> where 1,2,3 are slaves and 3,4,5 are masters. >>> >> -- >> Resources: >> - http://web2py.com >> - http://web2py.com/book (Documentation) >> - http://github.com/web2py/web2py (Source code) >> - https://code.google.com/p/web2py/issues/list (Report Issues) >> --- >> You received this message because you are subscribed to the Google Groups >> "web2py-users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to web2py+un...@googlegroups.com. >> >> For more options, visit https://groups.google.com/d/optout. >> > > -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
