Query between queries doubt.

[Gath]

Hi.

 

I know i read something about this someplace, but i looked and cant find it again.

 

The question is:

 

using PHP, i have a piece of code that does:

-query SELECT

-3 lines of code manipulating the result i got

-query UPDATE

 

The entire code takes a few ms of time to run.

 

 

Now, pretend two people are using the same file at the exact same time, is it possible for the user_B to have the SELECT in the middle of the SELECT-UPDATE of user_A?

 

I think i read someplace that the connection to hte DB would "halt" untill the entire script as run. Yes/no?

 

 

Thanks.

[teng84]

the script is read form top to bottom so what ever is on the top it is processed right before the script goes down.

 

@Now, pretend two people are using the same file at the exact same time, is it possible for the user_B to have the SELECT in the middle of the SELECT-UPDATE of user_A?

i guess it the algorithmic process of mysql can answer that but i guess it is SJF shortest job first

 

so if big query and small query is run on the same time small query will be run first

 

 

[fenway]

Yes, there can be another select in between... unless you're using transactions, there's not much you can do about it.