How to answer questions politely and correctly

Back in August I wrote a long post about how to ask questions politely and correctly to address what I see as a growing volume of poorly asked questions by people who often don’t have the common courtesy to be polite and also often come across as feeling entitled to an answer. Based on the responses, and private discussions, many of you out there see the same trend and are dismayed by it.

This is the necessary corollary to that post – how to answer questions politely and correctly, in my opinion – because I see people being discourteous and sometimes unprofessional in their replies. I’ve woven in some of the replies and private distribution list discussions I’ve had over the last two months as well – thanks to those involved – you know who you are.

I’ll start out by saying that some of you will disagree with elements of what I state below. That’s cool, this is just my opinion – vive la différence, and all that – but don’t expect to convince me to change my views. We’ll agree to disagree :-)

Ignorance is Not Stupidity

Probably the number one sin I see people committing when answering questions is giving an attitude to the original poster (who I’ll call the OP from now on) that they’re stupid/lacking/deficient/lazy in some way for not knowing the answer themselves.

Now, if a simple Google search would have found the answer, then I can understand some frustration on the part of the answerer, and I suffer from it myself, but that’s no excuse to be rude or belittling. I even shy away from posting Let Me Google That For You links in such cases as I think that comes across as too snarky, and I like to stay polite as much as I can. But sometimes I’ll just post a Google search URL (especially on Twitter), which does the same thing, but without the added snark, as that would just make me look angry. Others disagree with this sentiment, I know, and will happily post LMGTFY links – each to his/her own.

If it’s not a simple Google search, or I can tell from the question that the OP wouldn’t know what to search on, or how to make sense of the search results, or know which one to choose, then I’ll answer politely and explain the answer. Even if it’s something really simple about SQL Server. (Also check out the insightful comments about Google searches in the comment from @sqlhandle.)

As I explained in my post Ignorance is not stupidity back in 2011, everyone in the world starts with zero knowledge about SQL Server. I knew zero about SQL Server when I joined Microsoft from DEC in February 1999 (15 years ago – OMG – I’m getting old!! :-). Especially if the OP is someone you don’t know, give them the benefit of the doubt and treat them with respect for having the guts to ask a question publicly to get help. Don’t slap someone down for not knowing the answer. That’s the height of conceit, it’s bullying, and it’ll likely drive the OP away from our wonderful online SQL Server community.

Ok – that’s one of my hot-button topics done.

Posting Links in Question Answers

Here’s another one: posting links in question answers.

There was an interesting debate on the MVP email list a week or so ago about this, where someone said they hesitate to post blog post links as an answer because it can come across as self-promotion. I vehemently argued against that point of view, and I continue to believe that posting blog post links in the answer (or even as the answer) is entirely justified.

Self-promotion is where you’re posting something solely to get clicks on a link, or to drive traffic to your website for some business purpose – which of course is bad and you shouldn’t do it in the answer to a technical question – unless it’s directly relevant in some way. Posting a link to a blog post that contains the answer that the OP needs, or helps explain the answer, is certainly not self promotion. It doesn’t matter that the link is to a blog post on your company website, that’s just where you blog, and if it makes them aware of your company, then I think that’s fair recompense for your time in answering a community question. it’s not blatant self-promotion.

I also don’t buy the argument that a bunch of the contents of said blog post should be reiterated in the answer, just to give some meat to the answer in the thread so the thread is ‘self-contained’, or because blog posts move. One of the reasons I blog about things is so I can reference them in classes and online, so I can avoid repeating myself and point people at a deeper reference as part of answer, or as the complete answer. This is especially important for question mediums like Twitter.

If in doubt, consult whatever guidelines exist for the forum/distribution list/medium on which you’re answering. And if I just drop in a blog post link, I’ll always say something like ‘If you have any follow-up questions, feel free to ask’.

Now, saying that, you need to be very confident that your blog post is actually correct and actually answers the question (or contributes to your answer).

Answering the Actual Question

Which brings me to my next point: make sure you’re answering the actual question.

Often I see someone post an answer to the question that shows that either a) they didn’t read the question to see what the OP was actually asking for, or b) they didn’t understand the question or what the OP was actually asking for.

This is quite prevalent on forums such as MSDN, where I’ll see people post just for the sake of posting to try to increase their forums points/score. This is just daft. What’s really interesting is that I don’t see this behavior at all on #sqlhelp, as the only merit gained from answering questions on Twitter is community respect, not some silly score. Other forums do it better by allowing up and down voting, which increases of decreases your score. I applaud people who answer lots of questions correctly, but if you’re only doing it to have a higher score than everyone else, then IMHO you need to go out and get a life.

Don’t post at all if you don’t know the answer and can’t help, otherwise you’re just noise that’s obscuring the answer for the OP and putting people off from following and helping out in that forum. This is what stopped me answering corruption questions on MSDN and other forums – having to continually (nicely) correct people who were answering incorrectly and then being berated for it.

If there isn’t enough information in the question to answer it correctly, ask for more information. Don’t just assume. Or maybe give a couple of different answers, for different conditions or SQL Server versions, state as much, and ask for clarification. If you assume some piece of information that can change the answer, you may be doing a huge disservice to the OP by giving them an answer that’s wrong for their situation.

Don’t just answer: It Depends.

Much of the time the answer really does start with It Depends, but you then need to explain why it depends, what it depends, how it depends, etc. It Depends is a valid start to an answer IMHO. See my post It Depends. It really, really does for more on this.

If you don’t have time to answer properly, don’t answer at all. A half answer, or a non-answer wastes everyone’s time. Step away and let someone else answer.

If the medium where the question is being asked isn’t appropriate to the question, direct the OP at an alternative medium. For instance, if someone posts a #sqlhelp question on Twitter asking for an explanation of whether to use one join type or another, or a comparison between mirroring and availability groups based on some facet of operation, they’ll be directed by someone to post the question on a forum so that longer answers can be given.

Summary

It all comes down to this: give a good answer, that answers the question, provides references if necessary, and leaves the OP feeling like they’ve had a good interaction with the SQL Server community.

Even if they don’t ask politely or correctly, don’t be a jerk when you answer. You can politely point out how to ask the question. The days of being able to hide anonymously on the Internet are well past – and your response is captured for all eternity, so take pride in answering politely and correctly.

Again, don’t be a jerk. Treat people with respect, and if they seem to be lacking in some way, educate them. But be nice about it.

Thanks

February 2015 Sydney IE2/IEPTO-2 class open for registration

We’ve managed to juggle some of our schedule around and found space to fit in our only class of 2015 in Australia, and it’s open for registration!

We’ll be bringing Jonathan and Erin with us to Sydney to teach our signature IEPTO-2 (formerly IE2) Immersion Event on Performance Tuning and Optimization.

The class will be February 23-27, and we’ve got a deep discount for prior students who’ve taken our IE1/IEPTO-1 class:

  • Regular price is US$3,995
  • Early-bird price is US$3,495 for registrations in 2014
  • Prior student special price is US$2,750

We’ll be giving registration priority to prior students as this is the only class we’ll be teaching in Australia in 2015, due to our schedule constraints.

You can get all the details on the class page here.

We hope to see you there!

Correctly adding data files to tempdb

It’s well known that one of the common performance issues that can affect tempdb is allocation bitmap contention. I discuss this, and ways to alleviate it, in these posts:

The current best advice around adding tempdb data files is enshrined in KB article 2154845. If you’re seeing tempdb allocation contention (see top blog post link above), then:

  • If your server has less than 8 logical cores (e.g. a one CPU server with 4 physical cores and hyperthreading enabled has 8 logical cores), use # tempdb data files = # logical cores, equally sized
  • If your server has more than 8 logical cores, start with 8 tempdb data files, and add sets of four at a time, equally sized, until the contention is alleviated

There are three problems that people often face when adding tempdb data files: matching the size of the existing files that are growing, adding a file doesn’t help with contention, and adding too many files.

Matching Existing File Sizes

This problem occurs when the existing tempdb data files are growing, and people find it hard to create additional files that match the size of the existing files.

There’s an easy method for doing this: don’t!

Don’t try to match the size of existing, growing files. Create the new files to be a bit larger than the existing files, then go back and increase the size of the existing files to match the size of the new files.

For example, if I have 4 tempdb data files sized at 6GB each, and they’re growing by 512MB every few minutes because of an ad hoc workload. If I decide to add 4 more files, I might decide to add the four new files at 10GB each, and then go back and do ALTER DATABASE [mydb] MODIFY FILE [DataFileX] (SIZE = 10GB) for each of the 4 existing files. Problem solved.

But also see the bottom section, where you may want to limit the total amount of space taken up by all your tempdb files if the only reason for extra files is to alleviate tempdb allocation contention.

Additionally, if you have one full data file, you may find that…

Adding a File Doesn’t Help

This is very frustrating when it happens to people because it gives the impression that adding tempdb data files does not help with allocation contention. However, there is a simple explanation for this phenomenon.

Consider the case where there is one tempdb data file. Obviously all the allocations have to come from that data file and with the right workload, allocation bitmap contention will result. After the server has been up for a while, and the workload has been running and using tempdb for a while, the single tempdb data file may become quite full.

Now let’s say that you decide to add one more tempdb data file. What happens to the allocations?

Allocation uses two algorithms: round-robin and proportional fill. It will try to allocate from each file in the filegroup in turn, but will allocate proportionally more frequently from files that have proportionally more free space than others in the filegroup.

In the case where one file is very full and the other file is very empty, the vast majority of the allocations will be from the new, empty file. This means that almost all the contention moves from the initially existing tempdb data file to the new one, without much alleviation of the overall contention.

If this happens to you, try adding some more data files so that the allocation system has multiple files that it will allocate from, spreading the contention over those files and leading to an overall drop in contention and increase in transaction throughput.

But beware of immediately…

Adding Too Many Data Files

This is the case where tempdb allocation contention is a problem and people immediately add a large number of additional files where fewer files would work just as well. The problem here is that additional disk space is used up for no real gain, which may or may not be significant in your environment, depending on the size of the files added.

Let’s do an experiment. Below is a screen shot of PerfMon measuring transactions per second in tempdb for a contrived workload that has 100 connections all repeatedly creating and truncating temp tables. It’s running on my laptop (8 logical cores) using SQL Server 2014 RTM CU3.

perfmon1

For the first third of the trace, there’s a single data file. For the middle third of the trace, there are two equally-sized files. For the final third of the trace, there are 8 equally-sized files.

Clearly there isn’t a big performance boost from having the additional 6 data files in the final third, but what’s the sweet spot?

Ideally you’d experiment with varying numbers of tempdb data files to find the sweet spot for your workload. However, that’s easier said than done, especially when you’re trying to standardize a tempdb configuration across multiple servers.

Here’s an example of a slightly different workload running under the same conditions on my laptop.

perfmon2

It starts with a single data file, then 2, 4, 6, and 8 (pausing perfmon between each file addition). In this case, it’s clearly worth it going to 8 data files. But would I make them all the same size as the initial data file?

No, not if the only reason I need the extra files is to alleviate the allocation bitmap contention. I’d lower the size of all the tempdb files, including the initial one, so I’m not taking up a huge amount of extra disk space for these files.

Just be aware that sometimes you don’t need to go all out and add a whole bunch of extra tempdb data files to get a performance boost.

Summary

The easiest way to alleviate tempdb allocation contention is to enable trace flag 1118 and to add more tempdb data files. Just be careful that you add the right number to help with the contention, you make all the files the same size, and that you take into account the total size of all the data files you’ve created, and possibly dial them all down a bit.

Enjoy!