Maintaining your indexes

Indexes are crucial to SQL Server performance. Having the right indexes might make the difference of day and night with your application performance – as I once talked here.

However, even having the right indexes is not everything. You have to keep them healthy. Indexes, as any other kinds of storage, is subjected to fragmentation. SQL Server works best if the index structure is compact and continuous, but with all of the inserts/updates/deletes, it’s inevitable to get fragmented. When the fragmentation grows, it starts affecting the performance of SQL Server: Instead of having to read just one page, it now have to read two, which increases both time and resource needed, and so on and so forth.

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Episerver caching issue with .NET 4.7

Update 1: The bug is fixed in .NET 4.7.1 (thanks to Pascal van der Horst for the information)

Update 2: The related bug is fixed in CMS Core 10.10.2 and 9.12.5. If upgrading to that version is not an option, you can contact Episerver support service for further assistance.

Original post:

If you are using Episerver and update to .NET 4.7 (even involuntarily, such as you are using DXC/Azure to host your websites. Microsoft updated Azure to .NET 4.7 on June 26th) , you might notice some weird performance issues. If your servers are in Europe, Asia or Australia, then you can see a peak in memory usage. If your servers in North America, then you can see the number of database calls increased. In both cases, your website performance is affected, the former can cause your websites to constantly restarts as memory usage reaches a threshold limit, and even more obvious in the latter. Why?

It was a known issue in .NET 4.7, as mentioned here: https://support.microsoft.com/en-us/help/4035412/fix-expiration-time-issue-when-you-insert-items-by-using-the-cache-ins

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Import a bacpac to SQL Server

This is more of a note-to-self.

I sometimes have to import a bacpac file from customer’s database (usually from Azure SQL database) to my local machine – . For most of the time it’ll be very easy when the databases are in .bak format, but for .bacpac file it can be pretty complicated.

Sqlpackage.exe is the standard tool to import the .bacpac file, and it can be found with the installation of Visual Studio (for example C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\Extensions\Microsoft\SQLDB\DAC\130) or SQL Server ( C:\Program Files (x86)\Microsoft SQL Server\130\DAC\bin ). Latest version should be used because they can support the older formats (.bacpac exported from older SQL Server version), but not the way around (older version might not support .bacpac files exported from newer SQL Server versions)

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Price optimizing: to be or not to be

It can be quite confusing when you first edit prices in Episerver Commerce. To your surprises, some of the prices you imported or edited might disappear, or change, without your consent! What happened?

To answer that question, it’s essential to know there are two pricing system in Commerce: IPriceService and IPriceDetailService.

They have some different characteristics, and one of them is very important: the default implementation of IPriceDetailService saves prices as-is, while the default implementation of IPriceService does not: it optimizes prices before saving. Prices which are best for customers will be favored over the “less good” ones.

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Episerver CMS performance optimization – part 1

Update: In Episerver CMS 11, released today (November 21st 2017), the simpleaddress router has been moved to the last of the route table.

Original post:

This is an unusual post – it is not about Commerce – my area of expertise, but about CMS. Recently I’ve been working on some support cases where SQL Server instance is on high utilization, and in some scenarios it eventually slows down the site. After investigation, it’s likely to come from a small, simple and helpful feature: Simple address.

CMS content can have a property named “Simple address”, which allows you to create a “shortcut” url for that content. So if you have one page with “name in url” as “contact-us” under a page name “about-us” under Home page, you can access it via https://mysupercoolsite.com/en/about-us/contact-us. Or you can set the Simple address for that page as “contact-us”, and then you can access it directly via https://mysupercoolsite.com/contact-us.

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Can Episerver Commerce support our catalog size?

One of the questions customers usually raise during evaluation of Episerver Commerce is : “Can it support our catalog size? We have (a very big number of ) entries. Will it work?”

The answer is (of course, as always): It depends!

I’ve seen “big” catalogs. Some big enough in number – 1 million entries catalogs are not very uncommon, and some are even (much) bigger. Theoretically, Episerver Commerce can support up to 512 millions 1 billion of entries (!), so you can have pretty much anything in your catalog until you reach a hard technical limit. Just for comparison, Amazon.com, which is arguably the biggest eCommerce site on the world, has about 500 millions SKU(s) in 2015. But the number of entries is not everything. There are several factors which determine your catalog “size”. the number of entries is an important factor, but there are several other factors as well.

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Tale from inside TransactionScope

One of the last things you want to get from your Commerce site is that the order data is gone. What can be more confused than if your log shows that the cart has been converted into a purchase order, you even got the PO number, but after that, the order disappears? It’s nowhere to be found, even if you look into database. It’s kind of magic, but not the kind of magic you would want to have.

But everything happens for a reason. And actually it’s with a good reason: data consistency.

Episerver Commerce has the concept of TransactionScope. Simply put, it allows two or more database operations to be done as atomic: Either all of them succeed, or all of them will revert back. If a TransactionScope contains 3 operations A, B, C, then even if A, B succeeded, but C is yet to commit, and something goes wrong, then A and B would be reverted.

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PS4 firmware 4.5 wifi problem fixed

And finally the much anticipated 4.5 firmware of PlayStation 4/4 Pro has arrived, with some very neat features: extended storage, custom themes. It’s a big improvement for PS4 users, well, almost: the firmware comes with a big problem for ones who are using wifi: the download speed is now terrible, and even worse, the lag in game is making the games unplayable. Before 4.5, I had no problem joining matches on Uncharted 4, and playing Titanfall was very smooth – ping is never more than 100ms. After 4.5, I can’t hardly join a match on Uncharted 4 (errors in connections), and the lag in Titanfall spikes to more than 2000ms, making the game totally unplayable. Test Internet Connection shows that I have a a few hundred Kbps upload and download, when the wifi connection is supposed to be 130Mbps (PS4 ony has 2.4Ghz wifi 802.11 b/g/n, only PS4 Pro has 5Ghz wifi), and my internet connection is 250/100Mbps, so that must be a big problem somewhere.

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The Catalog UI trade-off: performance or better UI

I supposed this is a well known feature, but I was asked more than once about it, so it’s better to write something here to clarify the confusions.

If you have some very, very big catalogs, you probably have seen this “notification” in Catalog UI

By default, the Catalog UI groups a product and its variations in a parent-children view (they are not exactly parent-children, by the way). However, to do that, it needs to know about all the entries in that specific category. If it’s a small category, it should be no problem, but if it’s big one, then it’s inevitable slow. The lazy loading which the catalog content list only loads the contents when you scroll to them is not helping in this matter. Moreover, the grouping introduces an overhead for the UI, and having too many groups can severely affect the performance. Trust me, you won’t like a sluggish UI.

This improvement was introduced way back – 7.11 if I remember correctly – thanks to my colleague Magnus Rahl. To this day it’s still valuable – the performance was improved – but not that much to remove the threshold completely (And the improvement to the catalog versioning in Commerce 9 should have nothing to do with this).

When you see this notification, and if you’re unhappy with it, you have two (primary) options: Either to sub-categorize your category – i.e. introduce sub categories so each will have a smaller number of entries. Or increase the value of threshold.

Each approach has its own disadvantages. Sub-categorizing might break your SEO, while the second approach will undoubtedly effect the UI performance. Your call!

Now – the tricky part – which number to configure in SimplifiedCatalogListingThreshold setting. Obviously, it must be greater than the biggest number of entries in a category. But how to obtain that number? I’ve seen the confusion to raise that value to 3000, 5000, or even 10000 and it’s still not working. No, you can’t guess, you have to know for sure.

One simple option is to look at Commerce Manager Catalog Management. There is a small text in right corner of the list which shows the number of entries in that category (No, it’s not available in the Catalog UI, but I assume it would be helpful?)

 

The nuke option is to look at the database. Usually we recommend to avoid manipulate the database directly, as it can be dangerous – but here is a little code which only queries data (so practical harmless)

Now you know the biggest number of the entries in a category – just change the threshold in setting. Try it and see if the UI Performance is acceptable to you.

1600 vs 1400 vs 1200 rpm washing machine

I got this question before – and now I bought one, I hope I can help you choosing the right washing machine.

You might have read other answers on the Internet – and yes most of them are saying a 1200 rpm washing machine is as good as a 1600 rpm one, in term of the dryness of the clothes.

Wrong!

That might be true with synthetic clothes – which are the easiest ones to dry. But for cotton, it’s a big different. I tried same clothes with both 1400 rpm and 1600 rpm and my clothes are noticeable drier when it comes out of 1600 rpm mode. 1200 rpm, of course, is not even close.

That means the time you need to dry it, as well as the consumption of the dryer, will be less.

And to endure 1600 rpm spinning speed, the washing machine must be sturdier and more balanced. In other words, it must be built better – so you can expect it to last longer. You can see that in same series, the higher model which supports 1600 rpm is always heavier than the lower end models. Yes – it’s to support the faster rotation.

So if you have cotton clothes, and if you can afford it, I would suggest to go to 1600 rpm one.