I did see Thread 1 <https://groups.google.com/forum/#!topic/memcached/thhwPzg0O9U/discussion> and Thread 2 <https://groups.google.com/d/topic/memcached/thhwPzg0O9U/discussion> as well. It also has some resources on this topic. Anyway, isn't the below pattern simple enough? Do we need any more complication in my scenario? Would help if you can clarify. Thanks.
Thanks, Nishant On Saturday, June 4, 2016 at 7:04:58 PM UTC+5:30, Nishant Varma wrote: > > I am reading > https://github.com/memcached/memcached/wiki/ProgrammingTricks#ghetto-central-locking, > > it seems to deal with a slightly different lock scenario of getting some > expensive item from Database to avoid "Stampeding" > > In my case its slightly different lock that I need. I show regular files > from a folder in a web application to many users. So, to "lock" a file > using memcache isn't this simple API sufficient or I still need that > pattern :-)? > > def access(filename): > if memcache.add(filename, timestamp): > return "Access Granted. Lock Obtained" # Normally this results in > checking HTML checkbox against the filename so User can do actions with > that/ > else: > return "Access Denied" # Normally this leads to an alert saying > that someone else is working on this. > > Isn't this simple API using add good enough in my case? I am sorry if I am > repeating this, but I could not really relate the "fetching expensive item > from Database" to my scenario which is why I even wrote a simple script to > test the validity of the claim etc. > > Can you please let me know? > > > On Saturday, June 4, 2016 at 6:42:35 PM UTC+5:30, Nishant Varma wrote: >> >> Excellent I rely on you. I guess this is the reason you say I am >> over-engineering this problem. Makes sense :-) I will again check the link >> you gave me. I will go through the documentation this weekend. >> >> On Saturday, June 4, 2016 at 1:33:04 PM UTC+5:30, Dormando wrote: >>> >>> Hey, >>> >>> You really don't need to test this: I'm telling you flatly, as an author >>> of this software and all of the documentation for it, that you should >>> absolutely not rely on that pattern. I'm trying to save you some time. >>> >>> The pattern that is slightly better is written explicitly in pseudocode >>> in >>> the link I gave you several times in the issue. Please use it. >>> >>> Thanks, >>> -Dormando >>> >>> On Fri, 3 Jun 2016, Nishant Varma wrote: >>> >>> > Can anyone help me peer review this script >>> https://gist.github.com/varmanishant/0129286d41038cc21471652a6460a5ff >>> that demonstrate potential problems with get set if it is used >>> > to implement distributed locking. I was suggested to modify from get >>> set to add in this thread >>> https://github.com/memcached/memcached/issues/163. However I wanted a >>> small >>> > simulation to demonstrate this. >>> > >>> > -- >>> > >>> > --- >>> > You received this message because you are subscribed to the Google >>> Groups "memcached" group. >>> > To unsubscribe from this group and stop receiving emails from it, send >>> an email to memcached+...@googlegroups.com. >>> > For more options, visit https://groups.google.com/d/optout. >>> > >>> > >>> >> -- This e-mail message (including any attachments) may contain information that is confidential, protected by the attorney-client or other applicable privileges, or otherwise comprising non-public information. This message is intended to be conveyed only to the designated recipient(s). If you have any reason to believe you are not an intended recipient of this message, please notify the sender by replying to this message and then deleting it from your system. Any use, dissemination, distribution, or reproduction of this message by unintended recipients is not authorized and may be unlawful. -- --- You received this message because you are subscribed to the Google Groups "memcached" group. To unsubscribe from this group and stop receiving emails from it, send an email to memcached+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
