check have a low network traffic, i think it´s a nice command 2011/3/18 Les Mikesell <lesmikes...@gmail.com>: > On 3/18/2011 3:12 PM, Oleg Romanenko wrote: >> >> Hi. >> >>> How could this be put to use? i.e. when is knowing that >>> something exists at some point in an ephemeral store useful to an >>> application? >> >> This command provides support for lazy read operation. You can read >> the value of the key only when is really necessary. >> For example: >> 1. I am storing some information about the client in memcached. The >> key - is the name of the session, which is is given to the client. >> 2. I have a lot of service scripts that should check the rights of >> clients. They need only to know whether there is a key (then >> everything is OK) or not (then the client is redirected to the login >> script). >> 3. And I have only two scripts that use the value of a key in they >> work. >> >> Of course, this problem can be solved by creating an additional (flag) >> key(s) without content. But such approach is less secure and in >> generally reduces the consistency of system's data (for example, key >> with data can be deleted when the flag key still remain available). > > Seems odd to not care about the content in a cache where you aren't > guaranteed any relationship from one access to the next. That is, don't you > have situations here where a check would say a key exists but when you try > to retrieve it, it doesn't (expired, evicted, deleted by a concurrent > operation, etc.)? > > -- > Les Mikesell > lesmikes...@gmail.com > >
-- Roberto Spadim Spadim Technology / SPAEmpresarial
