4 ms·

If any DB is taking 50ms to reply (SQL, NoSQL, even MS Access!), something is seriously wrong. If you're using Rails, I'd fire up NewRelic or something like th

If any DB is taking 50ms to reply (SQL, NoSQL, even MS Access!), something is seriously wrong. If you're using Rails, I'd fire up NewRelic or something like that and check out what on earth is going on. Of course, 300ms is also way too long. Do you mean under stress-testing, with request queuing? 300ms is a mind-boggling quantity of CPU cycles...

cmelbye 17y ago
If we were to use MySQL, we'd be using multiple complex queries to get the job done. From what I've seen in New Relic on Heroku, queries have generally taken about 40-50 total for one request on PostgreSQL. We're building a general purpose method of running Ruby applications, so 300 ms is certainly a possible request time (including database, processing things, and rendering a view) for some applications that we may be running.
- justinsb 17y ago
  I think your performance here stems more from configuration than from MySQL vs Redis. If you're using Redis in-memory, if you dedicate the same amount of memory to your database, you should get roughly comparable performance between MySQL/PostreSQL and Redis. The under-the-hood differences if you're in memory just aren't that great, particularly because modern machines have such ridiculously powerful CPUs. Yes, it sounds like you'll have to do table join(s); yes, the joined tables need indexes; yes, you have the SQL parsing overhead; yes, it's a B-tree rather than hash-based indexing. But I'd be very surprised if you ended up with the order-of-magnitude differences you're suggesting. One of the things we're working on with FathomDB is ways to identify slow queries and help figure out what to do about them. If you're game, you can contact me with the queries and the table structure you were using in SQL and I'll try to figure out what's going on!

4 ms·

If any DB is taking 50ms to reply (SQL, NoSQL, even MS Access!), something is seriously wrong. If you're using Rails, I'd fire up NewRelic or something like th

by justinsb 17y ago

cmelbye 17y ago
If we were to use MySQL, we'd be using multiple complex queries to get the job done. From what I've seen in New Relic on Heroku, queries have generally taken about 40-50 total for one request on PostgreSQL. We're building a general purpose method of running Ruby applications, so 300 ms is certainly a possible request time (including database, processing things, and rendering a view) for some applications that we may be running.
- justinsb 17y ago
  I think your performance here stems more from configuration than from MySQL vs Redis. If you're using Redis in-memory, if you dedicate the same amount of memory to your database, you should get roughly comparable performance between MySQL/PostreSQL and Redis. The under-the-hood differences if you're in memory just aren't that great, particularly because modern machines have such ridiculously powerful CPUs. Yes, it sounds like you'll have to do table join(s); yes, the joined tables need indexes; yes, you have the SQL parsing overhead; yes, it's a B-tree rather than hash-based indexing. But I'd be very surprised if you ended up with the order-of-magnitude differences you're suggesting. One of the things we're working on with FathomDB is ways to identify slow queries and help figure out what to do about them. If you're game, you can contact me with the queries and the table structure you were using in SQL and I'll try to figure out what's going on!