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by falcolas 4576 days ago
> All of our development staff are capable of diagnosing these issues and providing suggestions.

I hope you're paying them well, because if they're all crack DBAs on top of being crack developers, they're the proverbial unicorn, and are probably worth $2-3 hundred thousand apiece.
1 comments
csmuk 4576 days ago
No they just know how not to fuck up their queries to start with so we don't need a DBA to optimise 300 join statements...
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falcolas 4576 days ago
Knowing how to write good queries and indexes is admittedly 80% of having a good performing database. However, as with any other 80/20 split, the remaining 20% is the hard part, and you'll end up paying a specialist to take care of it for you.

Or your dataset and query volume will not grow to the point where you actually need a performant database, but that's a business problem, not a DB solution.

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waps 4576 days ago
I wonder how much of your business is represented by startups and really capable development teams ... and how much is making hibernate perform better (or should I say "less horrible").

Development teams that go after speed will soon realize that re-serializing the data they need for a web page push and sending it over the network results in a factor 5-50x drop in performance over having that data in a local data structure. And God forbid you have even minor packet (like 0.0000001%) loss in the network between your webserver and database server. Your 99% tail latency will sprint for the 10s mark.

And as the DBA's here said : most databases are in the GB range, with a few in the tens or hundreds. SQLite will beat the crap out of any other solution at those sizes.

People don't realize how much tail latency affects maximum QPS. Once you calculate how one affects the other you see that tail latency is the enemy of performance in webservers. A webserver that can generate 100% of responses in 1ms can serve 1 million qps (ie. can saturate a 10Gbps link). At 99% at 1ms and 1% at 10ms (the very minimum to execute a single query against a database that isn't local to your machine), you're left with 900k. More typical database figures would be 20ms average and 600ms for the 1%, which will leave you with 30k QPS. In this example using a database cost you 97% of your original performance.

That 97% figure is perfectly normal. So if you want decent performance, using a database server (in the serving path) is just not in the cards at all.

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