Great. Congratulations. How big is the latency in the FDW? This opens up new possibilities using redis. Very cool.
On Wed, Jan 28, 2015 at 5:19 PM, Leon Dang <ld...@nahannisys.com> wrote: > > Andreas Kretschmer wrote on 01/28/2015 03:36 AM: > >> > I've implemented a completely new Redis FDW module which has little to >> do with >> > github.com/pg-redis-fdw/redis_fdw; although I did take some >> inspiration from in >> > on how the tables were to be designed but most I got from looking at the >> > oracle-fdw. >> > >> > My redis-fdw implementation supports read and write to the Redis >> backend, so >> > you can do insert, update, and delete. e.g. you can define a hash table >> as: >> >> is it possible to write multiple row's into the redis? something like >> >> insert into foreign_redis_table select * from big_table >> >> > Thanks for pointing this out. I had a small bug which didn't let it > succeed, but now it's been fixed and committed; I've also added a > bulkdata.sql test script in the code to show an example. > > > Anyway, thx, compiled and installed (just for fun, i'm not familiar with >> redis, and i'm not a coder) >> >> > Redis is great for session management as it allows you to set an expiry > for each key. So by using redis_fdw, you don't need to do multiple queries > to determine of the session is still valid. e.g.: > > -- use a string (key-value) dataset for user sessions > CREATE FOREIGN TABLE rsessions( > sessid TEXT, > value TEXT, > expiry INT > ) SERVER localredis > OPTIONS (tabletype 'string'); > ALTER FOREIGN TABLE rsessions ALTER COLUMN sessid OPTIONS (ADD param > 'key'); > > -- a user table in postgres, can contain a whole bunch of other fields. > CREATE TEMP TABLE users ( > userid INT, > username TEXT, > sessid TEXT > ); > > > -- > -- get user's details at the same time as determining if they're session > is still valid > -- > WITH u AS (SELECT * FROM users WHERE username = 'foo') > SELECT u.*, r.value, r.expiry > FROM rsessions r, u > WHERE r.sessid = (SELECT u.sessid FROM u); > > > > If the user's session is still valid then a row will be returned (Redis > automatically destroys the key on expiry). > > > -- > -- to reset the expiry timeout for the user > -- > UPDATE rsessions SET expiry = 40 WHERE sessid = $1; > > > > Leon > > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general > -- George R. C. Silva SIGMA Consultoria ---------------------------- http://www.consultoriasigma.com.br/
