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Announcing Live Office Hours on Wednesdays & Thursdays

Brent Ozar
Company News
3 Comments

Office Hours - ask me anything.It’s time for summer school!

I’m doing live streaming on my Twitch channel on Wednesdays & Thursdays this summer, and the recordings will go live later on my YouTube channel. I’ll take questions from PollGab, do live coding, work on the First Responder Kit, and write blog posts.

The stream will start at 8:15AM Pacific, 11:15AM Eastern, and you can see the time in your local time zone here. I’ll stream for around 45 minutes.

To get notifications when I go live, follow me on Twitch, or Google Calendar users can use this invite. See you in Twitch!

What SQL Server People Should Know About Amazon Aurora Serverless

Brent Ozar
Amazon Web Services (AWS), PostgreSQL
19 Comments

You, dear reader, are most likely a Microsoft SQL Server user – either a DBA or developer.

Set your pencil down for a second because you’re not going to learn about a Microsoft product today, nor are you going to learn something that is going to be immediately useful to you in your job. Today, I’m writing about a completely different product just to give you a better insight on what else is out there.

Our SQL Server monitoring app, SQL ConstantCare®, uses AWS RDS Aurora PostgreSQL as its database back end. I wrote about that design decision five years ago, and since then, we’ve been really happy with both PostgreSQL in general and AWS Aurora in particular. We just didn’t have to spend time worrying about the database layer – for the most part, it just worked, in the same way Microsoft Azure SQL DB just works.

No matter what database platform you use, costs are split into two main parts:

  • The storage layer – where you pay for how much you store, and how many accesses you do (reads and writes)
  • The compute layer – where you pay for CPU & memory for the servers to process your ugly queries

Traditionally, us data people have wanted the fastest storage we could get, and the most compute power we could get. That led to problems with management because we bought really good stuff, and then… it usually sat around idle, unused. We had to pay a lot to handle the peaks of our workloads, and then we were locked into expensive stuff that rarely got hit hard.

Serverless can reduce those costs while simultaneously handling more bursts.

To help reduce costs and improve flexibility, several years ago, AWS introduced Aurora Serverless. Instead of paying for fixed server sizes (like 8 cores and 60GB RAM), Aurora Serverless:

  • Watches your query workload
  • Automatically adds & removes CPU & memory on the fly
  • And reacts automatically in milliseconds without dropping queries

Not minutes. Not seconds. Milliseconds. That’s bananapants. You just define a minimum and maximum size for your database servers, and Aurora automatically handles the rest, independently, for each replica. Instead of provisioning an 8-core, 60GB RAM server, you could say you want your config to swing anywhere from 2 cores and 4GB RAM all the way up to 64 cores and 128GB RAM. (More on the exact provisioning later.)

Somebody at Microsoft is going to be tempted to pipe up, “Yeah, we have serverless in Azure SQL DB too,” and I can’t help but respond in meme form:

Yes, that’s actually in the documentation, and it’s why you’re not hearing a lot of buzz about serverless here in the Microsoft & Azure communities. Azure balances load in minutes, not milliseconds, and drops connections at the worst possible time – when you’re under heavy workloads and the server isn’t able to keep up.

I suppose that’s serverless, in the sense that you lose the database server temporarily? Let’s move on.

Aurora Serverless was a perfect fit for SQL ConstantCare®.

SQL ConstantCare® consists of a small app that clients install and point at their SQL Servers. Once a day, that app polls all of their SQL Servers, exports diagnostic data to JSON files, encrypts it, and sends it to us. We can’t predict when it’s going to happen – it’s based on the schedule that users set up on their end, which tends to be even-hours (like noon or 4PM local time in their own time zone.)

When the files come up to us in AWS, we:

  1. Decrypt & extract them, and then load their contents into a database
  2. Run diagnostic queries, checking for problems, and build a list of things to warn them about
  3. Send them emails with advice

That application logic layer has been serverless (AWS Lambda) all along, and I wrote about that design decision as well. That’s paid off really well as we scaled to thousands of client servers because the workload is really bursty. We don’t wanna pay for lots of app servers to sit around idle most of the time, but when client files come in, we want to process the data as quickly as practical.

The problem right from the start? The database layer! AWS Lambda would see lots of incoming files all at once, spin up lots of workers to process all those files, and then – wham, all those workers would try to tackle the database server at the same time. Richie had to work hard to smooth out the peaks, or else we just kept DDoS’ing our own database server.

By switching to Aurora Serverless, the database could now better handle bursts of incoming files – while simultaneously cutting costs by downsizing capacity for the hours per day that we sat mostly idle.

When you create serverless replicas, you size them in Aurora Compute Units (ACUs). One ACU = 1 core and 2GB RAM. Because we wanted to make sure it worked, we picked:

  • Min replica size: 0.5 ACUs (that’s 1/2 a core and 1GB RAM)
  • Max: 32 ACUs (that’s 16 cores, 64GB RAM)

And then sat back and watched the replica automatically handle workloads.

Aurora resizes our database servers FREQUENTLY.

Here’s an average of the primary writer’s ACUs over a 24-hour span, in 1-minute intervals:

Don’t worry about the time zone or peak hours – just think about this being a 24-hour time span. On average, we have a few different bursts per day, but we generally range from around 2-3 ACUs (cores) up to around 28 ACUs (cores). But here’s where it starts to get wild – instead of looking at averages, let’s look at the MAX in each minute range:

Aurora is frequently slamming the gas pedal, taking us right up to 32 cores! We’re maxing out at 32 cores all the time throughout the day. And conversely, the min in each minute:

It’s slamming the brakes right down to 1-2 ACUs all the time.

Lemme rephrase those 3 charts: in many one-minute time spans of the day, our Aurora database server scales up and down automatically from 1 core to 32. All day long. In fact, it’s rare to have a 15-minute time span where Aurora didn’t ramp capacity up and down like crazy. Here’s the same set of charts in 15-minute intervals – first, maxes:

In most of the day, in any given 15-minute time span, we were hitting 15-32 cores. But for mins:

It dropped right down to 1-2 cores.

Again, this is night-and-day different to what Azure is doing. Microsoft’s all, “Hey, let’s think about this for a while and transition up and down over the span of a minute or two.” Amazon’s reacting with lightning speed, so as each query comes in, it gets the power it needs and our apps don’t notice the difference.

Admins have to ask new questions.

Because Aurora’s reaction time is so fast, it opens up totally new questions for performance tuning and cost management.

“Are we doing the right database maintenance?” Resource-intensive queries literally cost you money. We were spending around $50/day for storage throughput at one point, and one day’s cost suddenly shot to $250. After digging into AWS’s Performance Insights (which is fantastic, by the way), we determined that a surprise automatic index maintenance job had cost us $200. That experience changed the way we think about index maintenance, and for SQL Server admins, that would be especially eye-opening. Are you sure you need those index rebuilds? Can you prove that the server is actually getting faster for your money? Odds are, it’s not.

“Should we raise or lower the max ACUs?” If we raise it, then resource-intensive queries might be able to finish more quickly – but scaling up compute power doesn’t always result in a linear speed-up of queries. Just because you go from 16 cores to 32 cores doesn’t mean big queries finish exactly 2x faster. The question morphs into, “How low can we go? How low can we set the max without hurting our most valuable queries?”

“When we change ACUs, how does that affect IOPs?” When you add more ACUs, you get more memory available to cache data, which means you hit storage less frequently. When you reduce ACUs, you’re likely going to hit storage more. There are no dials to set for storage performance – Amazon manages that for you automatically, and just bills you for every IO you do. There’s no easy across-the-board answer here, either – the answer is going to depend on your own workloads. For SQL ConstantCare®, we’re constantly importing new data and querying it, so cache is less useful to us.

“Does serverless make sense for our workloads?” Does this scale up/down, cost up/down actually benefit your application either in terms of lower cost, or faster performance? For our particular workload, it was really funny when we first switched over – Aurora Serverless was almost exactly the same cost as our previous pre-sized, inflexible servers, hahaha! However, by tuning our max ACUs, we could more easily find a sweet spot where we could reduce costs without harming performance.

But here’s my favorite part of Aurora Serverless: it gives us the ability to run new product experiments without worrying about capacity. For example, since the very start, I’ve always wanted to have a completely free tier of SQL ConstantCare that alerts you about the most vital issues, like missing backups, database corruption, or an urgent patch. Before moving to Aurora Serverless, I didn’t want to test that out because a huge wave of free adoption might cause us database performance nightmares. Now, the database server isn’t holding us back from those issues. (So stay tuned for some fun experiments!)

“Does migrating from SQL Server to Postgres make sense?” By this point of the post, you might be jealous of this cool technology. Remember, though, that right at the beginning I told you that today’s learning wasn’t going to be too relevant to your current job. You don’t really wanna change an entire application’s back end from one database platform to another, regardless of how easy Babelfish might make it seem. Back end migrations rarely make sense. However, I just wanted to talk about this technology today so you could see what’s going on in other database platforms.

Besides, Microsoft’s surely working on similar capabilities for Azure SQL DB. I love how cloud databases turned into an arms race because they’re a real differentiator for cloud vendors.

If you liked this post, you’ll probably enjoy Ed Huang’s musings on building a database in the 2020s. He asks, “If we were to redesign a new database today from the ground up, what would the architecture look like?” To be frank, it wouldn’t look like Microsoft SQL Server, and between his post and mine, you’ll understand why. I’m not saying SQL Server is dead, by any means – but if you’re a developer building new-from-scratch applications in the 2020s, SQL Server probably isn’t your first choice, and that’s why.

[Video] Office Hours: Ask Me Anything at Sea

Brent Ozar
Videos
0

It was a dark and stormy morning, on the last day of my Panama Canal cruise. Before I perished, I sat down to answer your top-voted questions from https://pollgab.com/room/brento.

Here’s what we covered:

    >

  • 00:00 Start
  • 00:36 ClippyTheDBA: Hi Brent. How you keep up-to-date with technology in general and in SQL Server specifically?
  • 02:56 Björk: Should foreign keys be indexed from day1 or only when performance issues arise from lack of a NC index on the foreign key?
  • 03:55 ClippyTheDBA: Hola Brent. If you just started your consulting business, what thing(s) you would change or do differently (based on your current consulting business experience)? [Kind of Lessons Learned]
  • 06:00 Haydar: What bad stuff can we look forward to once SQL Server hits the max size for a data file? Any interesting stories of this happening in the wild?
  • 06:52 Eduardo: How do I find the worst performing query for a given app using the first responder kit?
  • 08:51 Netanel: Is it safe to overlap invocations of the tools in the first responder kit (i.e run sp_blitzindex at the same time of running sp_blitzcache, sp_blitzfirst etc)?
  • 09:48 Alex: Hi guru, Regarding your last office hours where you talked about 2022 version. I was planing to upgrade from 16 to 22, now you got me thinking. Should I upgrade to 19 instead as 22 is full of bugs?
  • 10:56 Gopher: What criteria do you use when picking cruise ship line A vs B?
  • 13:09 AGAnyday: I am in a shop with backup policies dictating full backups daily, Colleague DBAs say there was a research policy informing that course of action. What is the best gentle approach to convince the management to resort to full backups for weekends then do differentials every night?

Who’s Hiring in the Microsoft Data Platform Community? April 2023 Edition

Brent Ozar
Who's Hiring
7 Comments

Is your company hiring for a database position as of April 2023? Do you wanna work with the kinds of people who read this blog? Let’s set up some rapid networking here.

If your company is hiring, leave a comment. The rules:

  • Your comment must include the job title, and either a link to the full job description, or the text of it. It doesn’t have to be a SQL Server DBA job, but it does have to be related to databases. (We get a pretty broad readership here – it can be any database.)
  • An email address to send resumes, or a link to the application process – if I were you, I’d put an email address because you may want to know that applicants are readers here, because they might be more qualified than the applicants you regularly get.
  • Please state the location and include REMOTE and/or VISA when that sort of candidate is welcome. When remote work is not an option, include ONSITE.
  • Please only post if you personally are part of the hiring company—no recruiting firms or job boards. Only one post per company. If it isn’t a household name, please explain what your company does.
  • Commenters: please don’t reply to job posts to complain about something. It’s off topic here.
  • Readers: please only email if you are personally interested in the job.

If your comment isn’t relevant or smells fishy, I’ll delete it. If you have questions about why your comment got deleted, or how to maximize the effectiveness of your comment, contact me.

Each month, I publish a new post in the Who’s Hiring category here so y’all can get the latest opportunities.

[Video] Office Hours: Ask Me Anything About SQL Server in Costa Rica

Brent Ozar
Videos
4 Comments

Off the coast of Costa Rica, I went through your top-voted questions from https://pollgab.com/room/brento.

Here’s what we covered:

  • 00:00 Start
  • 00:30 gotqn: In SQL Database we have “sp_invoke_external_rest_endpoint”, but in SQL Server 2022 still have not. Is using SQL Server Machine Learning (sp_execute_external_script) a good alternative or nasty hack?
  • 02:19 Chase C: If you had complete authority to focus Microsoft on fixing or adding a feature to SQL Server, what would you choose?
  • 03:52 I like hot pot: Hi Brent, is any of your client using Sql Server 2022 in production and if yes, how bad is it?
  • 04:56 Peter: Hi Brent, our devs are writing parameterless table functions opposed to views. Beyond the extra syntax required to create them is there a demonstrable downside or should I just step away even though I think it is hiorrible.
  • 05:36 Jr Wannabe DBA: Hi Brent, what do you think it is the best way to trigger (fire and forget, do not wait for result) an external application action from an INSERT into a SQL table? Looking for a direction, not full solution. Thanks in advance.
  • 06:36 Mr. SqlSeeks: Upgrading our Azure VMs. Our folks suggest using a VM size that has burstable IOPS. I think about troubleshooting performance issues and scalability testing, having to figure out if things were executed during a burst or not. I feel like I want consistent IOPS in Prod. Thoughts?
  • 07:49 Mike: If hosting AlwaysOn Availability Group on Azure VMs – can I have, say, 1 server (replica) with 32 vCPU, 2nd server with 4 vCPU, and 3rd server with 8 vCPU? Will AG with different size replicas work fine? And, can this affect data synchronization in some way?
  • 09:03 chandwich: Hey Brent. Have you ever had a client refuse to let you install your sp_Blitz stored procedures? If so, how did you handle that situation?
  • 10:18 TheyBlameMe: Hi Brent. What’s your preferred strategy when updating a limited downtime production system from an int PK parent table to bigint?
  • 11:42 Netanel: When is a high perfmon value for skipped GHOST records per second ever a concern? sp_BlitzFirst is reporting 53k skipped ghost records per second.

Is SQL Server 2019 More CPU-Intensive Than SQL Server 2016?

Brent Ozar
SQL Server 2019
72 Comments

I’m running into something that I’m having a hard time believing.

A client was hitting CPU issues during load testing, and they swore all things were equal between their SQL Server 2016 and 2019 environments. The 2019 box was having CPU pressure issues that didn’t show up on the 2016 box. I’ve played this game before, and every time, the root cause has been different configurations between the two servers.

However, this time, not only were the servers the same, but I’m even seeing this same behavior with a simple query that I can reproduce on any 2016 vs 2019 setup. I haven’t tested on any other versions yet, but after a day of banging my head against the wall, I figured it was time to bring in the smart people – and that means you, dear reader.

Take any two identical servers, and I do mean identical – same CPU speeds, same power savings settings – and run this setup script. We’re creating a database in 2016 compat level just to compare the exact thing across all versions:

Then turn on statistics time, and run this query:

The query’s terrible, of course, but it’s designed to do a fixed amount of CPU work every time. We’re not disk-bottlenecked – the tiny numbers table fits easily in memory. You’re going to be tempted to change the table design or query design, and you’re absolutely welcome to, but make sure the query is CPU-bottlenecked, not read-bottlenecked.

Compare the CPU time (not duration) across SQL Server versions. Because I’m paranoid, I built a brand new Windows Server 2016 box from scratch up in the cloud, and installed two instances of SQL Server on it. Left hand window is SQL Server 2016, right hand window is 2019 RTM – don’t run them at the same time, obviously, because that would screw up the CPU availability:

SQL Server 2019 uses 5-10% more CPU time to execute the same query.

It’s not just single-threaded queries, either – if I let the query go parallel by removing the MAXDOP 1 hint, 2019 is still slower:

You’re also going to be tempted to say, “Just change the compat level, query, or indexes to make the whole thing go faster on 2019” – but that’s not the point, because often we can’t tune an entire running workload. (In this demo case, 2019 compat level actually works beautifully, dropping the CPU time down by about 1/3, and I wish the client’s case was that easy. They already tried that before they called me. Bummer.)

You’re also going to be tempted to say, “I bet it’s fixed in a 2019 Cumulative Update,” in which case, check out this wider screenshot. The far right window is 2019 CU19, the most current one, and it exhibits the same higher CPU usage as 2019 RTM:

You might even be tempted to say it’s the new lightweight query profiling – try turning that off:

And at least in my tests, it makes no difference.

That’s where you come in.

If you have access to absolutely identical environments (or different versions installed on the same base hardware), are you able to replicate these findings? Does the same query use more CPU time on 2019 than it did on 2016? The best evidence for this is a side-by-side screenshot of the same query’s output across the different versions.

For our own evil purposes, 2017 doesn’t really matter (because you’ve gotta get to current versions anyway), but if you want to test on, say, 2016 vs 2022, you’re welcome to. In our brief testing, we’ve seen 2022 exhibit the same CPU problems as 2019.

I wouldn’t use this case as evidence that 2019/2022 are “bad” by any means – they’re fine. It’s just helpful for folks to understand, when they’re doing capacity planning for new versions, that they may have to buy more licensing for the same server at upgrade time. In this particular client’s case, we’re probably going to have to bump from 8 cores to 10 cores in order to handle the same workloads – in their cases, the CPU difference is closer to 20%.

This is the Last Week of Free PowerShell Training.

Brent Ozar
PowerShell
11 Comments

You’ve been working hard all month to get through our newest class, Fundamentals of PowerShell for DBAs. This week, it all starts to come together as you put together PowerShell plus SQL Server to automate tasks on a regular basis:

If you couldn’t keep up, no worries – you can always purchase the course, or pick up my Recorded Class Season Pass Fundamentals to revisit the material when your schedule is less hectic. Hope you enjoy the free training!

Office Hours: Questions That Didn’t Make the Cut

Brent Ozar
Production Database Administration
18 Comments

Sometimes, y’all post questions at https://pollgab.com/room/brento and they don’t get a lot of upvotes, and reading through ’em, I bet it’s because other people don’t quite understand what you’re asking. I think there might actually be a good question at the heart of it, but … I’m just not sure what it is, and it needs to be rephrased.

Here’s a rundown of some of ’em that came in recently. If you recognize one of these as yours, you’re welcome to re-submit it at PollGab, but with clarification.

MonkeySQLDBA: Recently watched one of your video on fragmentation, great stuff. quick question, if your fill factor is set to 80, will the internal fragmentation get to 70% faster than leaving fill factor to 0?

Zoom out: what problem are you trying to solve? What’s the action that you would take based on this knowledge? Think about those, and then re-post the question.

Piotr: If SQL Server and PostgreSQL were aircraft which aircraft models would they be? F14 vs SU57?

I love the question, but I don’t know enough about aircraft to answer it. I don’t even know if those two airplanes are good, bad, or the same, hahaha.

Keith: Hey Brent! Is it safe to upgrade my Azure SQL database from compatibility level 140 to 160 just to be able to run the GENERATE_SERIES function?

Is it hard for you to create a numbers table? Like, really? I’m not being sarcastic, but if you need a list of numbers, why wouldn’t you just create one?

I Cannot Do This Alone: I’m sure it has always been hard to get skilled help, BUT… have you ever heard of “non-tech” companies sharing there tech talent in like a pool? I know I’m on the hook for a trashing here, but better by you than my CIO 😉

I think you’re describing outsourcing – having a group of full time tech employees that you can call on whenever you need them, and just pay for what you use.

Brent Reading Book
“Can you show us your feet?” Wat?!?

Henry: I am planning on an in place SQL Server upgrade from SQL Server 2012 to 2016 on a Windows Failover Cluster. All of my databases are in Full mode with Transaction logs taken every 5min. Should i put the databases in Simple during the upgrade?

Don’t upgrade in place, period.

Government Cheese: How do you like to measure IOPs for SQL Server storage (bare metal and cloud VM)?

First, I don’t, but even if I did – are you talking about measuring how many they already consume, or how much a new server provides? If you’re asking how many they already consume, how is that useful? You don’t know if the users are happy or not, or if you need to reduce storage throughput or increase it.

ConsultantWannabe: Hey Brent, you teach we should stand next to expensive things (like SS or Oracle) as contractors/consultants, any advice to identify our own expensive thing to stand next to? Obviously apart from standing nex to SS. Thanks

Are you … asking me … how to find out how much things cost? I’m confused. Why wouldn’t you just … ask management what the most expensive thing in the shop is?

Jeremiah Daigle: I have a server that has 2 8Core CPUs, and only have 8 enterprise core licenses. I was planning to just remove one of the CPUs, but ran into issues not having the blank to put back in. Is there anything to be concerned about by turning down each CPU to 4 cores in bios instead?

Having a blank to put in? I’m not sure what you mean – you shouldn’t need a “blank” CPU. I think someone’s pulling your leg, like they’re telling you to go get blinker fluid.

Maksimilian: What’s the best technique for a SQL sproc to self audit the params it was called with?

Self audit? Have the proc log them to a table. (I think I might be misunderstanding the question because it seems so obvious, but if you want to log something, and you’re in a database, well, uh, put it in a table.)

Eduardo: Linked-in provides automated public notification of completed course training. How should DBAs notify potential employers of completed Ozar training?

You mean … how do you add things to your resume in LinkedIn? I’m genuinely confused – are you asking how to edit your resume? I’m guessing you just click Edit on your profile, right? Put in whatever text you want there. If you’re saying that you have a problem because you need automation every time you complete any of my courses, and I have so doggone many of them, then stop putting each one – just put Fundamentals and Mastering.

Hangman: When is sp_whoisactive context_switches a useful metric for performance troubleshooting?

Ask whoever told you to look at that metric. Otherwise, don’t walk into the airplane cockpit, point at a gauge, and ask the pilot, “Hey, what’s that dial mean?” That’s not an effective use of anyone’s time. SQL Server is way worse than an airplane cockpit: there are precisely 1.21 gigawatts of metrics out there, and most of ’em just aren’t useful.

Eduardo: Is it good idea to start identity integer cols for new fast growing tables at the max negative value for a big int? Do you see this much in the field?

It’s fine. I almost never see it.

Tony: Will you be purchasing TSQL fundamentals 4th edition?

No. I’m sure it’s good, and I’m sure you doubt my T-SQL abilities, fair enough, but I’ve moved on to learning other stuff.

Isaac: How do you find all the queries that are using the kitchen sync query pattern (Col1 = @Col1Val or Col1 IS NULL) AND (Col2 = @Col2Val or Col2 IS NULL)? How do you find the worst of the worst?

Instead of looking for anti-patterns, ask, “What are the 10 worst-performing queries that I need to tune, and what are the anti-patterns in those?” That’s what sp_BlitzCache does.

TheCuriousOne: Hi Brent! From your perspective, is there any open problem/issue preventing a problem free upgrade from SQL Server 2019 to 2022 and if so, what are the gotchas to look out for?

Microsoft used to publish detailed upgrade guides for each version of SQL Server, but they stopped doing it. Check out the most recent one from 2014 (PDF) and that’ll give you a rough idea of how complex it is to migrate an existing environment.

Eduardo: What is your favorite graph database and why?

I don’t use any myself, so I’m not qualified to answer that.

Wasn’t_Me: We are thinking about switching from Azure to AWS. On docs.aws.amazon.com I find this phrase: “When you set up an Amazon RDS DB instance for Microsoft SQL Server, the software license is included.” What?? Does it means that on AWS I don’t have to pay SSRS, SSIS, SSAS?

Licensing is included in the hourly rate, yes. Amazon also offers bring-your-own-licensing. Keep in mind that you said RDS, and RDS doesn’t have SSRS, SSIS, and SSAS – you’ve got a lot more reading to do. Fortunately, I’ve got a training class to help.

Marian: Hi Brent! Have you even been to Romania? Would you consider attending some big tech event in Romania in the nearby future?

No, and since the pandemic, I’ve cut back a lot on my conference schedule. I’m sure Romania is nice, but I did a quick Google search and didn’t see any SQL Server conferences in Romania. I’m not really interested in non-SQL-Server conferences – when I want to learn other technologies, I tend to use cheaper/easier methods rather than traveling.

Neil: I set up all my SQL servers with TCP/IP enabled only. A developer is trying to connect with named pipes. Should I enable named pipes or force them to use TCP/IP?

I don’t have any opinion on this one whatsoever. (I don’t think I’ve ever disabled named pipes.) Why did you disable it?

[Video] Office Hours in Cartagena, Colombia

Brent Ozar
Videos
1 Comment

Before heading out to Old Town for sightseeing, I went through your top-voted questions from https://pollgab.com/room/brento.

Here’s what we covered:

  • 00:00 Start
  • 00:44 Haydar: Is there a good way to suppress part of TSQL batch from showing the query plan in SSMS but having the rest of the batch show the query plan?
  • 02:13 Mike: Hi Brent, so simple blocking on a busy server, can cause a failover ? Is it because of exhaustion of thread workers, resulting in THREADPOOL waits? But I can’t understand the mechanism, how this can lead to failover – could you please explain ?
  • 03:03 Greef Karga: Please describe the most strict / locked down environment you have worked in and the challenges it posed.
  • 06:11 Q-Ent: Hi Brent. Have you ever used buffer pool extension as an option for better performance?
  • 07:29 Hangman: When is sp_whoisactive context_switches a useful metric for performance troubleshooting?
  • 08:36 AFriendOfMineAsk: Howdy Sir! Our CTO wants a monthly dashboard of all Production SQL Servers, can you please give some advice or any tips on what KPIs should include or should i have to start looking for a new job? Thanks and have a great day Sir!
  • 09:57 Jester: What tool do you like to use to find the worst performing queries with implicit conversions?
  • 10:55 Yaakov: What is the best way to print the line number currently executing inside a TSQL Sproc? 11:45 AM, no I’m not a morning person.: using where X in (1,2,3,4,5, etc) for selecting random sets of items. Is there any performance reason not to do this and instead use parameters or put them into a temp table first? Is it right to assume this won’t be able to be a cached query?
  • 12:59 Mike: Since 2005, new version of SQL Server had been released every 2, maximum 3 years. What is your opinion on when the next version (after 2022) will come out ? Will it be late 2024, sometime in 2025, or later, and why ?

It’s Monday. Do You Know Where Your PowerShell Training Is?

Brent Ozar
PowerShell
2 Comments

You’re over the hump! Just two weeks left to go.

All month long, I’m giving away our newest class, Fundamentals of PowerShell for DBAs. Here’s what you’ll be learning this week:

In case you didn’t know before now, go head over to the class and watching the Before the Class modules that explain how to set up your workstation to follow along.

Not patient? Can’t wait for the rest of the videos to go live? Recorded Class Season Pass Fundamentals holders can jump in now – it’s included with your existing membership. Enjoy!

Slow Startup, Failover, and Restore Times with In-Memory OLTP

Brent Ozar
In-Memory OLTP (Hekaton)
16 Comments

When In-Memory OLTP came out, I worked with it briefly, and I remember coming away thinking, “Who in their right mind would actually use this?” I was so horrified that I wrote a presentation about it and gave it at a couple of conferences:

Many laughs were had, but obviously that didn’t make me any friends at Microsoft, ha ha, ho ho. I figured I was done with Hekaton, and I wouldn’t ever have to see it again because y’all all saw the video, and you’d never be crazy enough to implement that feature.

<sigh>

Well, here it is in 2023, and recently I’ve talked to a couple of architects who wish they could go back in time and watch that video. In both cases, they suffered from the same issue.

The short story is that the more data you put into durable In-Memory OLTP tables – and even just 5GB of data can hit this issue – the more your startups, failovers, and restores turn into long stories, to the point where other databases on your SQL Server are practically unusable.

Setting up the 5GB Votes table

To demonstrate the problem, we’ll start with a large copy of the Stack Overflow database. I’ll drop my nonclustered indexes just to make the next screenshot more clear, and then I’ll list the tables in the database to find a good candidate for the demo.

The highlighted table, dbo.Votes, has about 150 million rows and takes up about 5GB of space. That’s not big data by any means, and we can easily fit it in memory on our 8-core, 60GB RAM server. Let’s migrate it into In-Memory OLTP in order to make performance go faster:

After migrating that 5GB table to In-Memory OLTP, it’s taking up 5GB RAM, right? Well, no:

Try 28GB RAM. That’s why we have a sp_Blitz check to warn about high memory usage for In-Memory OLTP:

As to why an uncompressed 5GB rowstore table takes up 28GB RAM, that’s a topic for another blog post. (Sometimes, I imagine rowstore tables being introduced today – people would think they’re the most amazing thing ever.)

What happens when SQL Server restarts?

For most of us, when we restart SQL Server, our biggest concerns are things like dropping connections, losing performance metrics, and starting over again with a fresh buffer pool. In-Memory OLTP users have a bigger problem: when the SQL Server restarts, CPU goes straight to 100%, and stays there:

Ouch. Why is CPU so high? Because with In-Memory OLTP, SQL Server starts up the database by reading the In-Memory OLTP tables up into something we call “memory.” It’s using less memory than before, thank goodness – it’s “only” 13GB – but 13GB of data still takes a long time to pull from disk and reconstruct in memory. (I’m not going to go into technical terms like crash recovery phases here because it’s not necessary to convey the overall problem.)

You can see exactly how long it takes in the SQL Server logs. In this case, the StackOverflow database recovery took 50 seconds – and in this case, because our server’s got really fast storage, the storage was able to deliver data so quickly that it pegged CPU at 100% for all 50 seconds.

During startup, wait stats show a lot of wait times on XTP_PREEMPTIVE_TASK and SLEEP_DB_STARTUP:

There’s also blocking, which is kinda funny – anything that needs to query sys.databases gets blocked, like IntelliSense queries running in the background:

This happens during failovers, restores, and attaches, too.

Startups, failover clustered instance failovers, and restores all exhibit the same problem: they need to start up the database, and doing that means reconstructing the In-Memory OLTP data from scratch.

This is particularly problematic for shops that use Always On Availability Groups. Say you want to add a new database into an existing cluster, and the new database happens to use In-Memory OLTP. You restore it on the primary, and … boom, the server hits 100% CPU usage for an extended period of time, which affected all the running queries on existing databases on that server.

Here’s what CPU looks like at the end of a database restore:

CPU was relatively low while the restore was processing, but once SQL Server was done writing the files, CPU went straight to 100%. Why? Because it needed to bring the database online, which meant reading the In-Memory OLTP data from disk and reconstructing the table.

Even if you just attach an In-Memory OLTP database – a process that is normally near-instantaneous – you bring SQL Server to its knees while it reads through that data and populates memory.

In my example, I don’t have indexes on the In-Memory OLTP table, but if I did, the situation would be even worse. Indexes on these tables are only kept in memory, not on disk, so they’re reconstructed from scratch at startup, failover, restore, and attach time.

Bottom line: the more In-Memory OLTP durable data you have,
and the more databases you have that use it,
the worse this gets.

Trace flags 3408 and 3459 don’t help on SQL Server 2022, at least.

Among other sources, Konstantin Taranov’s excellent trace flag list reports that trace flag 3408 forces all databases to use just one thread when starting up. I don’t think I’ve ever needed to use that trace flag, but it doesn’t appear to help here. In my lab, I set up 3408 in the startup config, restarted the SQL Server, and CPU still went straight to 100%:

Furthermore, 3408 doesn’t appear to have the desired effect on SQL Server 2022 (and I didn’t bother checking on other versions, since it wouldn’t have helped my client, as they had a lot of databases with In-Memory OLTP.) Databases are still starting up with multiple threads, which would drive CPU to 100%:

Same problem with trace flag 3459, which is supposed to disable parallel redo for AGs, but that’s unrelated to database startup, as we can see by the flames:

And just because someone’s going to ask, no, setting MAXDOP to 1 has no effect on system processes like bringing databases online.

So how do we get faster startups, failovers, and restores?

In theory, you could add CPUs. In practice, that’s a really expensive way to solve this problem, and it doesn’t work when you have several (or heaven forbid, dozens) of databases that use In-Memory OLTP. SQL Server doesn’t just start up one database at a time – it starts them in groups, which means you can saturate lots of CPUs on restart. If you need to dive into the internals of this, here are a couple of resources:

In theory, you could use slower storage. Bear with me for a second: if your primary concern was that other databases on the SQL Server were unusable while In-Memory OLTP databases came online, you could actually put the In-Memory OLTP filegroup on slower storage. In this 5GB Votes table example, that does actually lower CPU usage during most of the process, only driving it to 100% near the end of the process:

(Yes, I actually tested that for one particular client, who was curious.) However, that also makes the In-Memory OLTP databases take even longer to come online! In my example with a 5GB table, the database took ~80 seconds to come online instead of ~50 – making your RTO goals tougher to meet.

In practice, minimize what you keep in In-Memory OLTP durable tables. A few ways to do that:

  • Make them schema-only instead, and don’t keep the data around. Yes, you lose all data when the SQL Server goes down, but if you’ve been using this feature for temporary data anyway, like session state, reconsider whether you need to keep it.
  • Sweep older data out to conventional tables. One of Microsoft’s design patterns for this feature is to use In-Memory OLTP tables only for ingestion, but then after the data’s been absorbed into the database, archive it.
  • Use regular tables instead, not In-Memory OLTP. Conventional tables don’t interrupt startup.

[Video] Office Hours at Sea: Heading to Jamaica

Brent Ozar
Videos
0

I’m on a boat! I’m on a 10-day Panama Canal cruise, and I stopped (well, not the boat) off the coast of Florida to answer questions y’all posted at https://pollgab.com/room/brento.

  • 00:00 Start
  • 00:56 DBe: In several places I’ve worked, it’s been “policy” to automatically restart heavy-use SQL servers off-hours on a regular cadence. Usually monthly but in a couple cases weekly. Is the scheduled restarting of SQL servers a common, viable business practice?
  • 03:53 BBDD: Hey Brent, do you know why a heap with one nvarchar100 column and 1row can be with size 2 GB and all used.What might have happened to the poor table. I tried to reproduce it creating the same table with inserting, deleting truncating but the size when it was back to 1 row was 1mb
  • 04:52 Brandon: Changing order of joins made a BIG difference for me recently, I suppose b/c it helped SQL start in a better place on the search for a good plan before time ran out. This was on 2008. Have you run into this much & do you think it’s less of an issue after 2008?
  • 06:04 Gigiwig: Hi Brent, a friend of mine has a server instance with a sql_… collation. One of the dbs is from a vendor and insists on a different collation. Can that cause problems concerning joining to system tables, using tempdb? How did you handle collation mismatches in the past? Thx
  • 07:43 Pamela Anderson: Has the problem introduced by PSPO implementation in SQL Server 2022 CTP – impossibility to tell which statement relates to which batch (or SP?), that you blogged about last year – been actually fixed in 2022 when it came out ? Or we have monitoring broken ?
  • 08:35 Runyan Millworthy: What are the top signs that a shop needs more SQL DBA’s?
  • 11:22 Kajimial: Hugs Brent, watched your video for optimizing checkdb? Isn’t with physical_only supposed to be faster? I ran it on 8TB db and completed for a little bit over a day and just checkdb completes for 6h? How can this be possible? DB with no load and running it with maxdop 0 with Ola
  • 13:27 Craig Gardner: I’m doing a penetration test on a server and have come across a SQL Server. Build number is 12.0.937.0 and version is 2014 (although I doubt this). I can’t find any information on that build number. Do Microsoft have a list of build numbers for Azure Managed Instances?

Who’s Hiring in the Microsoft Data Platform Community? March 2023 Edition

Brent Ozar
Who's Hiring
14 Comments

Is your company hiring for a database position as of March 2023? Do you wanna work with the kinds of people who read this blog? Let’s set up some rapid networking here.

If your company is hiring, leave a comment. The rules:

  • Your comment must include the job title, and either a link to the full job description, or the text of it. It doesn’t have to be a SQL Server DBA job, but it does have to be related to databases. (We get a pretty broad readership here – it can be any database.)
  • An email address to send resumes, or a link to the application process – if I were you, I’d put an email address because you may want to know that applicants are readers here, because they might be more qualified than the applicants you regularly get.
  • Please state the location and include REMOTE and/or VISA when that sort of candidate is welcome. When remote work is not an option, include ONSITE.
  • Please only post if you personally are part of the hiring company—no recruiting firms or job boards. Only one post per company. If it isn’t a household name, please explain what your company does.
  • Commenters: please don’t reply to job posts to complain about something. It’s off topic here.
  • Readers: please only email if you are personally interested in the job.

If your comment isn’t relevant or smells fishy, I’ll delete it. If you have questions about why your comment got deleted, or how to maximize the effectiveness of your comment, contact me.

Each month, I publish a new post in the Who’s Hiring category here so y’all can get the latest opportunities.

I’m Coming to Boston for SQLSaturday!

Brent Ozar
Conferences and Classes
2 Comments

I’m coming back to Boston for SQLSaturday this October 14th!

On Friday the 13th (muhaha), before the event, I’m teaching a one-day pre-conference workshop on Mastering Query Tuning.

Mastering Query Tuning

You need to speed up a SQL Server app, and you’re allowed to change the queries and indexes – but not the server hardware or settings. Good news – I’ll teach you how in a day of learning and fun. Join me, Brent Ozar, as I explain how to make your SQL Server apps go faster.

We’ll cover:

  • How SQL Server builds query plans
  • How to choose between CTEs, temp tables, and APPLY
  • How to tune for SELECT * and lots of rows
  • How to write dynamic SQL that scales
  • How to avoid pitfalls like deadlocks and bad batching

Save $50 on early bird registration now. The class will be held at the Microsoft Technology Center at 5 Wayside Road, Burlington MA 01803. Seating is limited to 114 folks. I will be there in person, and it will not be recorded or broadcast online.

Other helpful links:

I’m Coming to Gothenburg and Oslo This Fall!

Brent Ozar
Conferences and Classes
4 Comments

Back in 2020 before the wheels came off the world, I’d scheduled visits to Gothenburg and Oslo for their annual SQL Server events. Now that things are back to normal, it’s back on!

Data Saturday Gothenburg, Aug 26 & 28, 2023 – Monday Post-Con: Mastering Server Tuning – You’re constantly facing new performance challenges on different servers. You need to quickly diagnose a server’s bottleneck, and learn the most common ways to fix each bottleneck. Let’s tackle it together in a fast-paced 1-day version of my full 3-day class, and because we can’t cover everything, attendees get a year’s access to the full 3-day recorded class too. Learn more and register for the workshop now.

Data Saturday Oslo, Sept 1-2, 2023: Friday Pre-Con: Mastering Query Tuning – You need to speed up an existing app, and you’re allowed to change both queries & indexes, but you can’t throw hardware at it. Let’s tackle it together in a fast-paced 1-day version of my full 3-day class, and because we can’t cover everything, attendees get a year’s access to the full 3-day recorded class too. Learn more and register for the workshop now.

Can You Nest Transactions in SQL Server?

Brent Ozar
T-SQL
5 Comments

To find out, let’s set up a simple status log table:

And then let’s try a two-part transaction:

Right now, SQL Server shows that I have 2 open transactions:

What Happens If I Roll Back?

But what does “2 open transactions” mean, really? If I do a rollback, what gets rolled back? Let’s find out:

The results:

Both of our transactions were rolled back, and there’s nothing left in the table.

Let’s Try It Again, but Commit This Time

Roll through the same setup code, but then commit:

The results are a little weird:

Only one transaction is shown as open – and right now, both rows are in the results table. If we roll back now, what happens?

Even though we said we “committed” our inner transaction, it doesn’t matter – BOTH of our transactions got rolled back.

You Can’t Really Nest Transactions Like This.

Think of @@TRANCOUNT as the number of times remaining that you either need to commit or roll back. If you open a bunch of nested transactions in a row, it’s up to you to commit every single one of ’em. If ANY of them are rolled back, EVERYTHING is rolled back.

This is particularly troublesome if you try to break up locking by using a bunch of little transactions wrapped in one big outer transaction. I recently had a client who thought they could:

  1. Start an outer transaction for a business process
  2. Start an inner transaction, acquire locks on OrderHeader, make changes, commit, and release the OrderHeader locks when the transaction committed
  3. Go on to another inner transaction, acquiring other locks on OrderDetails, while other processes were able to work lock-free on the OrderHeader table because step 2’s locks were released

But as you can see here, even when you commit one part of a transaction, SQL Server still isn’t quite done with it. It has to maintain those locks because if any of your open transactions are rolled back, SQL Server’s gonna roll back everything you did – even the parts you thought were finished.

Update: a couple of commenters have pointed out SAVE TRANSACTION, and I gotta say I’m not a fan of that because of the complexity, especially around lock escalation. If you choose to use that feature, read the documentation really carefully, especially around lock escalation. Saved transactions don’t release the locks once they’ve been escalated, and if you’ve been through my Mastering classes, you know how easy it is to hit lock escalation.

Find 40 Problems in This Stored Procedure.

Brent Ozar
T-SQL

Aaron Bertrand posted a challenge:

We’re going to use the AdventureWorks sample database (get your copy here), where the folks in marketing requested a list of users to e-mail a new promotional campaign. The customers need to meet at least one of the following criteria:

  • last placed an order more than a year ago
  • placed 3 or more orders in the past year
  • have ordered from a specific category in the past two weeks

These criteria don’t have to make sense! They just need to make the query a little bit more complex than your average CRUD operations.

First, we’re going to update Sales.SalesOrderHeader to modern times so that dates make sense relative to today. We only care about OrderDate here, but there are check constraints that protect a couple of other columns (as well as a trigger that sometimes fails on db<>fiddle but that I have no energy to troubleshoot):

This stored procedure that someone wrote will now return data (without the update, it would be hard to write predictable queries based on, say, some offset from GETDATE()).

Now, it’s your turn: how many bad practices can you find in that code?

Aaron’s answers are over here. I’ve turned off comments on this blog post because if you have any questions or thoughts, you should post ’em on Aaron’s blog post. The only reason I’m posting this here is that I bet a lot of y’all aren’t subscribed to Simple Talk, and I wanted to break this challenge up into two parts – the code to review, and the answers. Do not look at the answers until you’re done with your code review. Have fun!

Office Hours: Short Text Answers Edition

Brent Ozar
Production Database Administration
1 Comment

Not all of the questions y’all post at https://pollgab.com/room/brento require long-winded responses.

Brandon: Do you seen a rise in json queries to address impedance mismatch between data/objects? I struggled with EF to produce a query that was neither simple nor complicated against a properly designed db (according to 2 experts). Dropped EF; used json query in stored proc; it was magic.

Brent OzarNo.

Rufus: What are the best ways to determine if two large query plans have the same shape?

Put them side by side in SSMS and zoom out.

Stan Redman: What is your opinion of the SQL force encryption setting?

I don’t do security or compliance work, so I have no opinion.

Dance Monkey: Do you think there would be much interest for someone to host a PostgreSQL office hours on Youtube/Twitch?

Yes.

Eduardo: What is highest number of DBs you could safely put in an always on availability group?

Read this.

Marian: Hi Brent! Would you recommend any SQL Server Certification that would be easily recognizable? I know Microsoft retired those on SQL Server, and focus on Azure.

No.

Hondo: What is the top batch requests per second (sustained) that you have seen in the field? What were the specs for the underlying hardware to support that kind of load?

At the moment, 150K sustained, 4 socket, 64 core box with 256GB RAM. Small data set, just lots of tiny well-tuned queries that can’t effectively be cached client side.

Rooster: How do you determine the the optimal Virtual Memory page file size for bare metal Windows Server 2019 running SQL Server 2019 Enterprise?

Read this.

Sigríður: Is there anything we can do to to influence the stat sampler so that a given index key (customer in this case) is included as one of the histogram 200 steps? We know who the top 200 most important customers are by $$$$.

Yes, filtered statistics. They’re just like filtered indexes – put a where clause on ’em.

Tim: Greetings Brent. Are you winging it? Or do you sneak a peek at pollgab before starting the stream, so that you’re prepared? If you are winging it, how long did it take until you were confident in your knowledge and no longer had to prepare?

This one takes a little longer to answer, but I’m putting it in this batch because it’s fun.

Before starting the show, I look at the PollGab queue to remove anything that might be offensive or isn’t a good fit for my show (like if someone asks a MySQL question.) In the process of looking at ’em, I at least see what’s coming. I don’t ever go Google for stuff – either I know the answer, or I’m going to tell people what I’d Google, but that’s it.

How long did it take? Well, Office Hours is a really good simulation of what it’s like to be a consultant. Client staff constantly throw questions at you, and you have to be really comfortable either saying you know the answer, or saying you don’t, but you know where you would look. You can’t feel guilty about saying you don’t know. So I’ve been really comfortable with what I do know for a long time – but it’s just that the scope of that surface area slowly and steadily grew over time.

I still make mistakes! In a recent show, I said I didn’t think unique constraints also created a unique index under the hood. One of the viewers pointed out the mistake. Strangely, I get excited about that because it means I still have stuff to learn!

Updated First Responder Kit and Consultant Toolkit for February 2023

Brent Ozar
First Responder Kit Updates
0

Thanks to this technique to run SQL Server on Apple Silicon chips, I’m now developing exclusively on my Mac! I’ve been using a Mac for over 15 years, but in the past, I’ve always used Windows at some layer somewhere. This time around, it’s all Mac the whole way down, which is kinda nifty. Makes my release process easier.

How I Use the First Responder Kit
Wanna watch me use it? Take the class.

To get the new version:

Consultant Toolkit Changes

I updated it to this month’s First Responder Kit, but no changes to querymanifest.json or the spreadsheet. If you’ve customized those, no changes are necessary this month: just copy your spreadsheet and querymanifest.json into the new release’s folder.

sp_BlitzCache Changes

  • Enhancement: when using @SortOrder = ‘all’, there’s a new pattern column to show which metrics sucked about the query, and it’s included in the table output. (#3172, thanks Adrian Buckman.)
  • Fix: case sensitivity issues on joining to sys.all_columns. (#3233, thanks sm8680.)

sp_BlitzFirst Changes

  • Fix: QRY_PROFILE_LIST_MUTEX lock timeouts on sys.dm_exec_query_statistics_xml. (#3210, thanks sqlslinger.)

sp_BlitzLock Changes

  • Fix: error converting data type nvarchar to bigint. (#3201, thanks Erik Darling.)
  • Fix: arithmetic overflow in wait_time_hms when wait time added up to more than 2147483647. (#3215, thanks Vlad Drumea.)
  • Fix: string or binary data would be truncated in table tempdb.dbo.#deadlock_owner_waiter. (#3206, thanks johnkurtdk.)

sp_BlitzWho Changes

  • Fix: shows procedure definition even if the current statement isn’t in the plan cache. (#3163, thanks Adrian Buckman.)
  • Fix: tempdb allocations did not include internal objects such as worktables and workfiles. (#3174, thanks Adrian Buckman.)

For Support

When you have questions about how the tools work, talk with the community in the #FirstResponderKit Slack channel. Be patient: it’s staffed by volunteers with day jobs. If it’s your first time in the community Slack, get started here.

When you find a bug or want something changed, read the contributing.md file.

When you have a question about what the scripts found, first make sure you read the “More Details” URL for any warning you find. We put a lot of work into documentation, and we wouldn’t want someone to yell at you to go read the fine manual. After that, when you’ve still got questions about how something works in SQL Server, post a question at DBA.StackExchange.com and the community (that includes me!) will help. Include exact errors and any applicable screenshots, your SQL Server version number (including the build #), and the version of the tool you’re working with.

[Video] Office Hours Brought to You by Quest Software

Brent Ozar
Videos
2 Comments

Today’s episode of Office Hours is brought to you by Quest Software. I went through your top-voted questions from PollGab.com/room/brento, and, uh, kinda looked like I was sponsored by Fendi while doing it, hahaha:

Wow, those logos are bigger than I thought. Here’s what we covered:

  • 00:00 Start
  • 01:20 reluctantly_tolerant : I used FCI instead of AG for server w/500 DBs due to worker thread limit. I used NetApp ONTAP filesystem and was very impressed by performance, and ability to spin up clone of production in under 2min. Now I feel this is the gold standard. Why go back to AGs, even where possible?
  • 02:42 Simon: First off: I know we should not use the NOLOCK hint :] But can NOLOCK queries even cause index corruption on queries that is NOT modifying data? Perhaps if combined with persisted computed columns? (SQL Server 2019, latest CU).
  • 03:58 LogarTheBarbarian: Hello hello Brent! What questions come to mind if you came upon MSSQL instances that modified the Ola DBCC CheckDB job to run CHECKTABLE, CHECKALLOC, and CHECKCATALOG on different days rather than CheckDB in its entirety?
  • 05:15 Dru: When should a unique constraint be used vs a unique index?
  • 06:32 Sigríður: What are your favorite things about living in San Diego and Las Vegas?
  • 08:38 Sigríður: What is your favorite standing desk and why? What are the specs?
  • 09:18 Peter Seale: VAGUE question: we found that 80% of our db data is used by indexes. Is this normal-ish? Any vague tips for reducing our data usage? Most tips focus on data used by tables, and never mention data used by indexes.
  • 09:56 Piotr: What are your thoughts on upgrading from SSRS2014 where we have numerous reports? Best to migrate to SSRS2019 or skip entirely and starting learning how to migrate to PowerBI server? Currently on-prem but planning on moving to Azure.
  • 12:54 Maksim: What do you use for motivation to read tech docs and tech books?
  • 14:05 PartyPerson: Hey Brent, what is the story behind the “California deserves whatever it gets” sign behind you?
  • 15:20 TeeJay: A lot of our reports are computationally expensive and run repeatedly for each subscription. I assume that the solution to this is to pre-aggregate the DW data as much as possible, but suspect that I’m probably re-inventing the wheel. (Budget: £0) What words should I be googling?
  • 16:34 Alex: Hi Guru, I have some small tables on Azure SQL DB with very little use. Once in a while a scheduler runs a SP that performs one insert to a table in 2 concurrent threads. I have a gap in identity column. I added TABLOCKX as suggested by docs but problem still arises.
  • 18:08 depthcharge: Hi Brent, have you ever encountered a scenario where you indexed to remove an eager index spool, and SQL Server ignores the index and continues spooling? Aside from index hints (which help, but we can’t change the code), any other clubs I can hit the optimizer with?
  • 19:13 toepoke.co.uk ;-): Hey Brent, In a recent office hours you spoke of encrypting data on the app side rather than the db side which I found interesting. How would this work from a sorting perspective, eg sort a UI table by Last name,First name, etc. Store the first letter ? Store the hash? Cheers!
  • 20:51 Q-Ent: Hi brent, are you aware of MCR(Maximum consumption Rate ) for CPU sizing? Do you think this is a reliable method ?
  • 22:01 Wren: Hi Brent! Building some reports for our SQL Server environments and I found one of your old (2009) replies on Stack about finding CPU time per database… do you think it’s a worthwhile stat to use to determine “what should move to cloud first”? Any improvements since SQL2008?
  • 23:23 Tim.: Hi Brent. I like the fundamentals of powershell. Will there be a mastering powershell? Will you be working with Drew more in the future?
  • 24:50 Stone Temple Pilot: How do you measure bad page splits for inserts on a poor clustered index?
  • 25:17 Paco: Hello Brent, I have a friend who is facing a server that has both threadpool waits and Non-Yielding Schedulers occurring around the same time, until they cause the AG to fail. Have you seen threadpool waits cause Non-Yielding Schedulers or vice versa?
Brent Ozar

Hi! I’m Brent Ozar.

I make Microsoft SQL Server go faster. I love teaching, travel, cars, and laughing. I’m based out of Las Vegas. He/him. I teach SQL Server training classes, or if you haven’t got time for the pain, I’m available for consulting too.

Want to advertise here and reach my savvy readers?