Tag: sqlserver

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)

Continue reading “Import a bacpac to SQL Server” →

Watch your indexes closely

Recently we were tasked to help a customer having a problem with a query. This specific query ate a lot of CPU resources (30-40%) and causing performance problem for other queries – as it slows the entire SQL Server instance down.

Upon investigation, we discovered that the query was accessing a table with an outdated index. The index was supposedly updated in Episerver Commerce 7.10.3, which was released almost 3 years ago.

For some reasons, the index was not updated in customer’s table. Instead of just having to do a index seek, SQL Server was forced to do a full table scan, which is much slower, causing the problem.

If you want to go into details, it’s mdpsp_getchildrenbysegment stored procedure, which looks into UriSegment column of CatalogItemSeo table, previously, the index was like this:

CREATE NONCLUSTERED INDEX [IX_CatalogItemSeo_UniqueSegment_CatalogEntry] ON [dbo].[CatalogItemSeo]
(
    [ApplicationId] ASC
    [UriSegment] ASC,
    [CatalogEntryId] ASC
)

You can see the problem: The order of the index was bad – because ApplicationId was not distinctive (in fact, in most of the cases it’s the same for every row), and because UriSegment was not the first column in the index, this index will not be used if a query uses UriSegment only. Continue reading “Watch your indexes closely” →