Fixing a stored procedure

At Episerver development team, we understand the importance of good performance. Who would not like a lightning fast website? We work hard to ensure the framework is fast, and we seize (almost) every opportunity to make it faster.

You know in Commerce 10.2 we introduced a new cart mode – serializable cart, and it’s proven to bring great performance compared to the “old/traditional” approach. Our own tests showed an improvement of 3-5x times faster. But can it be even faster? Probably yes.

And actually we did some improvements in later versions. In the scope of this blog post, we will just focus into a specific aspect – and to learn a little more about SQL Server performance optimization.

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Lessons learned from a “boring” Black Friday

This Black Friday, I was in a task force, ready to help high profile DXC Commerce customers to cope with a peak in traffic. It turned out to be boring – there was no moment I could be a hero and “save the day”. Things went surprisingly smooth, even for websites which were struggling with last Black Friday. I went home and was little dissatisfied, but deep down, I know it was a huge success. The hard work from us (Commerce development team), them (the partner development teams), and Managed Services has been well paid off.

Use the latest version

You have heard me saying this, and you will probably hear from me again: Please, use the latest version possible. There is no reason to stay with an old version. This is a little truth: I hurt a little deep inside whenever I read a question on world asking a question about Commerce 7.5, or even 8.x. You should be using at least 10.8 by now, if not 11.x.

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Please, rebuild your database indexes, now

I will make it quick and to the point: if you are expecting a lot of customers visiting your site tomorrow (and you should) for Black Friday, you should rebuild your database indexes, now.

On average, it will help you to serve more customers and they will be happier with a more responsive, faster website. On best cases it will help prevent catastrophes.

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Read only Catalog UI – part 1

https://world.episerver.com/forum/developer-forum/Episerver-Commerce/Thread-Container/2015/6/read-only-catalog/

A while back, we had this question on World. It’s not uncommon to update the catalog data by an external system, mostly from a PIM – Product information management system. In such cases, it might not make senses to enable editing in Catalog UI. You might need the new UI for the other parts, such as Marketing UI, but you wouldn’t want the editors to accidentally update the product information – because those would be lost, anyway.

Is there away to do it? Yes, there is.

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Beware of IContentLoader.GetChildren() for CatalogContent

This is more of a self-to-note.

If you are using IContentLoader.GetChildren<T>(ContentReference), one important thing to remember is this uses the current preferred language. Normally when you get children of a catalog, or a node, that would not be a problem, because a catalog entity – node or entry, will be available in every language supported by the catalog. So if you just want to get the children references, the language is not important. (Note that, if you just need the children references, IRelationRepository should be a faster, more lightweight way to go, but that’s another story). If you want to get children in a specific language – which is the most common case, you know that you can use the other overload of GetChildren<T>(ContentReference, ILanguageSelector) , where you can specify the language you want to load.

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Super charged Episerver Commerce performance

Well, that was the title of my talk at the last week Meetup in Lund – hosted by Avensia. My first time in Lund – it is a very beautiful (small) city. It was a very nice event with about thirty developers from inside and outside Avensia, and I hope I did give some good information to make your Commerce solutions faster!

Then it comes to my attention that some of you might be interested in the talk. Unfortunately I don’t think the talk was recorded (I’d have been famous on Youtube!), but here’s the slides from the talk:

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A curious case of SQL execution plan, part 2

Recently I wrote about how to look into, identify and solve the problem with a SQL Server execution plan – as you can read here: https://vimvq1987.com/2017/10/curious-case-sql-execution-plan/

I have some more time to revisit the query now, and I realized I made a “small” mistake. The “optimized” query is using a Clustered Index Scan

So it’s not as fast as it should be, and it will perform quite poorly in no cache scenario (when the buffer is empty, for example) – it takes about 40s to complete. Yes it’s still better than the original one, both in non cached and cached cases. But it’s not good enough. An index scan, even cached, is not only slower, but also more prone to deadlocks. It’s also worse in best case scenario, when the original one can use the proper index seek.

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A curious case of SQL execution plan

I said this, and I will repeat it here: SQL Server optimizer is smart, and I can even say that, generally, it’s smarter than you and me (I have no doubt that you are smart, even very, very smart 🙂 ). So most of the cases, you leave it to do whatever it thinks is the best. But there are cases SQL Server optimizer is fooled by the engine – it gets confused and chooses an sub-optimal plan, because it was given wrong, outdated, or incorrect information. That’s when you need to step in.

Today I face one case like that, as reported here: http://world.episerver.com/forum/developer-forum/Episerver-Commerce/Thread-Container/2017/10/database-timeout-on-productvariant-update/

(As a side note, I don’t answer direct questions, nor provide any personal support service (I would charge plenty for that 😉 ). I would appreciate if you go through World forums, or contact Episerver Developer support service. There are several reasons for that, including knowledge sharing, and work item tracking. I can make exceptions when I know the problem is highly urgent and is hurting your business, by jumping into it sooner than I’m expected to/before it’s escalated through several level of supports. But all in all, it should be registered with Deverloper support. We at development team are supposed to be the final line of support, not the front line. )

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Episerver Commerce catalog performance optimization – part 4

Recently I worked on a support case where a customer reported deadlocks and timeout exceptions on queries to a specific table – NodeEntryRelation. Yes, it was mentioned in this post. However, there is more to it.

Keeping the indexes healthy definitely help to improve performance and avoid deadlocks and timeout exceptions. However it can only work to a limit, because even if the indexes are in their perfect state (the fragmentation level is 0%), the query will still take time.

Looking in the query we talked about – ecf_Catalog_GetChildrenEntries – what does it do. It lists the entries which are direct children of a catalog. So normally entries belong to categories (nodes), but it’s possible (Although not recommended) to have entries that belong directly to a catalog.

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Reindex obsolete prices in Episerver Commerce

Recently I stumped upon this question:

http://world.episerver.com/forum/developer-forum/Episerver-Commerce/Thread-Container/2017/8/event-for-price-becoming-validinvalid/

which is very interesting to me. I can see this is a real scenario – and even quite common. When a price become obsolete, you want your contents to be reindexed so the next time you query, the search result will be returned correctly. But how?

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