mysql-native v2.1.0

[Nick Sabalausky (Abscissa)]

On 03/07/2018 02:32 PM, bauss wrote:
> 
> Wait why has it been updated to array() ? So it's not a real range 
> anymore? Or was it always represented as an array behind the scenes?
> 
> I just feel like allocating it into an additional array is a waste of 
> memory? But if it was always like that I guess it doesn't matter.
> 

query() returns an input range. You can only access one element at a 
time (as its read from the network) and you don't know how many there 
are ahead of time, BUT it avoids allocating a whole array to store 
everything.

In addition to query(), there used to also be a querySet(). The 
querySet() would allocate an array and read ALL the results into it so 
you could get random-access. But that's exactly what you already get 
when you call array() on an input range (such as the input range 
returned by query), so querySet was deemed redundant and eliminated.

So if you had code that *did* need an array allocated to store all the 
results, then "querySet()" has been replaced with "query().array". But 
like you said, if you don't really need the array, then there's no need 
to call array() and waste the memory.


> However idk what I changed, but the issue stopped for me.
> 
> However I still have this issue:
> 
> https://github.com/mysql-d/mysql-native/issues/153
> 
> (Currently trying to see if I can make a minimal example, but it's kinda 
> hard to make a minimal example since it's from my Diamond MVC (vibe.d) 
> library and it isn't used until deep nesting of the application.
> 
> Anyway before I report anything else I could easily be doing something 
> wrong. There hasn't exactly been any good examples on how to use it with 
> vibe.d so it has pretty much been a trial and error thing for me.

Using mysql-native with vibe.d isn't any different from using it without 
vibe.d.

It's recommended to use MySQLPool to make a Connection rather than doing 
"new Connection" directly simply because connecting is faster that way 
(though "new Connection" will still work).

But aside from that, there is absolutely nothing different about 
mysql-native whether you're using vibe.d or not.


> So basically I keep an associative array of connection pools based on 
> connection strings like below:
> 
> private static __gshared MySQLPool[string] _pools;
> 
> And then I retrieve a connection with the function below.
> 
> Perhaps I'm not supposed to make a new pool every time, but there is 
> someway to retrieve a pool already? Maybe that's what I'm doing wrong?
> 
> private static shared globalPoolLock = new Object;
> 
> private Connection getMySqlConnection(string connectionString)
> {
>    auto pool = _pools.get(connectionString, null);
> 
>    if (!pool)
>    {
>      synchronized (globalPoolLock)
>      {
>        pool = new MySQLPool(connectionString);
> 
>        _pools[connectionString] = pool;
>      }
>    }
> 
>    return pool.lockConnection();
> }
> 
> After I retrieve the connection then it's basically like the code I 
> showed you, but that seem to be correct, yes?

Does your application need to support multiple connection strings while 
it's running? That's pretty rare unless you're making something like 
phpMyAdmin (and even then, I'd probably do it a little differently). 
Normally you'd just make one connection pool:

MySQLPool pool;

Then "new" that once with your connection string when you start up, and 
you're good.

I guess I can imagine some potential use-cases that get more complicated 
than that, but that's really up to your own project's needs.

 > However I still have this issue:
 >
 > https://github.com/mysql-d/mysql-native/issues/153
 >
 > (Currently trying to see if I can make a minimal example, but it's kinda
 > hard to make a minimal example since it's from my Diamond MVC (vibe.d)
 > library and it isn't used until deep nesting of the application.

I'm only guessing here, but I wonder if that might be because you seem 
to be trying to share pools and connections across threads. I don't know 
whether vibe is designed to share TCP connections across threads or not. 
I'd say, try ripping out all that shared/__gshared/synchronized stuff 
and see how that works.