Stored Procedure VS. F#_问答_开发者_运维开发者技术经验分享

For most SP-taught developers, there are no option between Linq and Stored-Procedures/Functions. That's may be true.

However, there are a road junctions nowadays. Before I spending too much time into syntax of F#, i would like more inputs about where the power (and opposite) of F# lies.

How will F# perform on this topic (against SP)?

F# have to communicate with a database on some way. Through Linq2Sql/Entity-app-layer or directly though AnyDbConnection. Nothing new there. But F# have the power of parallellism and less overhead in thier work (Functional Programming with C#/F#). Also F# has it's effeciency as a layer for data and machine. Pretty much like C# power of being a layer between human and machine.

Would I really still let the DB Server handle a request of recurring nodes, or just fetch plain data to F# and handle it there? Encapsulated nice and smoothly as a object method call from C#?
Would a stored procedure still be t开发者_高级运维he best option for scanning 50 millions of records for finding orphans or a criteria that matching 0,5% of the result?
Would a SP or function still be best for a simple task as finding next parent node?
Would a SP still being best to collect a million records of data and return calculated sums and/or periods?

Wouldn't a single f# dll library fully built on the Single responsibility principle being of more use then stored procedures hooked up inside a sql server? There are pros and cons, of course. But what are they?

Stored procedures are not magically super-fast. Often, they're actually rather slow.

Many people will downvote this answer providing anecdotal evidence that a stored procedure once made an application faster overall. However, all of those examples that I've actually seen code for indicate that they totally rethought some bad SQL to package it as an SP. I submit that the discipline of repackaging bad SQL into a procedure helped more than the SP itself.

Most of your points can't be evaluated without a measured benchmark.

I suggest that you do the following.

Write it in F#.
Measure it.
If it's too slow for your production application, then try some stored procedures to see if it's faster. If it's fast enough for your production application, then you have your answer, F# worked for you. For your application. For your data. For your architecture.

There's no "general" answer. Although my benchmarks for some particular kinds of queries indicate that the SP engine is pretty slow compared with Java. F# will probably be faster than the SP engine also.

The important thing is to make sure that the database -- if it's going to be "pure" data -- is already optimized so that queries like your "scanning 50 millions of records for finding orphans or a criteria that matching 0,5% of the result?" would retrieve the rows as quickly as possible. This often involves tweaking buffers and array sizes and other elements of the database-to-F# connection. This usually means that you want a more direct connection so that you can adjust the sizes.

Databases are efficient for certain tasks (e.g. when they can uses index to search for a specified row), but probably won't be any faster than F# if you need to process all rows and ubdate them (in database) or calculate some new result based on all the data.

As S. Lott suggests, the best option is to try implementing what you need in F# and you'll find out. Parallelism can give you some performance benefits, especially if you're doing some computationally heavy calculations. However, you may still want to store the data in databases, load it and process it in F# (I believe this is how F# was used by adCenter at Microsoft).

Possibly the most important note is that databases give you various guarantees about the consistency of the data - no matter what happens, you'll still end up with consistent state. Implementing this yourself may be tricky (e.g. when updating data), but you need to consider whether you need it or not.

You ask this:

Would a stored procedure still be the best option for scanning 50 millions of records for finding orphans or a criteria that matching 0,5% of the result?

I take your question to mean 'I have this data in sql server. Should i query it in sql or in client code (F# in this case). Queries like this should absolutely be performed in sql if at all possible. If you're doing it in F#, you're transferring those 50 million rows to the client just to do some aggregation/lookups.

I hope I understood your question correctly.

As I understand an SP just means you call some precompiled execution plan, and you can call it through an API, instead of pushing a string to the server. These two save in the order of millseconds, nowhere near a second. For larger queries that difference is negligible. They're good for highfrequency/ throughput stuff (and of course encapsulating complex logic, but that doens't seem to apply here).

Because an SP uses a procompiled plan, it can indeed be slower than a normal query because it no longer checks the statitsics of the underlying data(becuase the execution plan is already compiled.) Since you mention a condition that applies to 0.5% of the rows, this could be important.

In the discussion of SP vs F# I would reword that to 'on the server' vs 'on the client'. If you're talking higher data volumes (50M rows qualifies) my first choice would always be to 'put the mill where the wood is', that means execute on the server if possible. Only if there is some very complicated logic involved you might want to consider F#, but I don't think that applies. Then still I'd prefer to execute that on the server than first drag all those rows over the network (potentially slow).