His question appeared to be an administrative rather than a legal one. He said once everything has been established to a judge's satisfaction how long does it take the judge to issue the warrant.
I can't really see any point to having an answer to that, but that's apparently what was asked.
It's like asking "once all evidence has been presented at a trial to establish guilt beyond a reasonable doubt how long does it take a judge to say 'guilty'?".
REPLY (Possibly In The Wrong Place; My PC Wants Its Sleep)
First, thanks to everyone who replied.
Second, why did I ask such a question? My question arose as a result of the reaction to a similar question asked by John Truman on the Expert Law site. I could see what the guy was driving at, but he seemed to me to be deliberately misunderstood. I hope he uses this site and saw how you guys replied. If so, he'll now know, assuming I've understood correctly, that the judge doesn't hold up the proceedings (which I think was his main concern, because I've seen that he's interested in how powerful figures affect ordinary citizens' lives), but the difficulty of compiling an adequate affidavit (all the things cited in your answers) to present to a judge means the process as a whole can take minutes, days, weeks, months, or years.
From what I've read elsewhere in the short time since I saw John's question, I believe a judge has a duty to grant a warrant promptly provided the appropriate criteria are met, which suggests a judge never delays the granting of a warrant on a whim. I doubt John Truman thought a judge did that, exactly, but who knows?
I suspect, but don't know, that occasionally a police officer applies for a warrant with weaker grounds than he'd like. The question that occurs to me (sorry, John, if you were all set to ask it!) is, can a police officer have more than one shot at getting a warrant, if fresh evidence comes along, or is he debarred from trying again if he got it wrong the first time? That would put tremendous (but not necessarily unreasonable) pressure on the officer. It sounds as if it can be a tough call.
I guess an outsider must often struggle with issues that aren't black and white in a profession not his or her own. Answers that seem to an insider to cover it all can sometimes leave an outsider wondering. I don't think that makes him dumb or them smart. It makes them good at their job and, for all anyone knows, he's good at his.
I've written a book. Sorry. And I hope John doesn't mind that I took his side.
Thanks again, all (and it's the jury that says 'guilty', not the judge).