Tag Archives: SQL Server

Unable to connect to named SQL instance on remote machine

Recently I was doing installation of K2 5.2 on Azure VMs with SQL server named instance hosted on separate Azure VM. I’ve created SQL Server alias on K2 VM but then run into issue – neither K2 Setup Manager nor SSMS were able to connect to SQL through alias. I next tried direct connection via server\instance name which also failed. SSMS showed me the following error:

Could not open a connection to SQL Server. Microsoft SQL Server, Error: 53

I first focused on network connectivity between VM:

  • Confirmed that I can ping SQL Server VM from K2 Server VM
  • Confirmed that no firewall enabled on VM and Azure VMs on the same network with nothing blocking connectivity between them
  • I tried to use telnet to test port 1433 – it failed

This is what kept me focused on network connectivity layer a bit longer then necessary. But after confirming that SQL Server not listening on port 1433 using netstat -na | find “1433” it became quite clear that focus should be on SQL Server configuration. First of all – by default named instance listen on dynamic port, and you actually need to have SQL Server Browser Service enabled to ensure you can connect to named instance without specifying port while using dynamic ports. But in my case it was not that as in SQL Server configuration there was explicitly specified custom port (SQL Server Configuration Manager > Protocols for %INSTANCE_NAME% > TCP/IP Properties > TCP Dynamic Ports – if you have anything other than 0 in IPAll section fir this setting you are not using dynamic ports). When your problem is dynamic ports and disabled SQL Server Browser Service error message from SSMS looks as follows:

SQL Network Interfaces, error: 26 – Error Locating Server/Instance Specified

As you can see error message explicitly tells you “Error Locating Server/Instance Specified. To fix this either set 0 for TCP Dynamic Ports setting and enable SQL Server Browser Service or specify some port number there. You sort of choosing your dependency here – either browser service (may fail to start) or custom port (may be hijacked by other service). It seems that browser service is better approach.

So in my case I was confused by expecting named instance to listen on default port which was, to put it simply, wrong expectation. Here is how you can check on which port your instance is listening:

Commands which you can use to find out your SQL Server instance ports

But obviously having access to SQL Server you can get this data from SQL Server Configuration manager too: SQL Server Configuration Manager > Protocols for %INSTANCE_NAME% > TCP/IP Properties. Just keep in mind that you need to check TCP Dynamic Ports value both for specific address and for IPAll section. But like I said in my case, the problem was not about ports. Once I found out instance port I noticed that I still cannot connect to it using telnet, just because IP address was not enabled in SQL Server Configuration Manager > Protocols for %INSTANCE_NAME% > TCP/IP Properties (meaning it had Enabled=0). I corrected that and telnet connectivity test succeeded.
Still, when I get back to SSMS I was getting the same error – “Could not open a connection to SQL Server. Microsoft SQL Server, Error: 53”. Reason? With SQL Server 2016 and latest versions of SQL Server, I keep forgetting that the latest and greatest version of SSMS still reads alias settings from x86 registry hive (meaning you need to configure SQL alias using cliconfg.exe from C:\Windows\SysWOW64) – I have a hard time getting use to it. Interestingly fully missing x86 alias triggers error message “Could not open a connection to SQL Server. Microsoft SQL Server, Error: 53” while one we configure with non existing server or instance name will give you “SQL Network Interfaces, error: 26 – Error Locating Server/Instance Specified”.

Anyhow your key takeaways from this post should be:

  • Know your instance port
  • Make sure that IP address is enabled
  • We still need to configure alias twice (x86/x64) to avoid unpleasant surprises from apps reading setting from non-configured location

I hope this post may save some troubleshooting time for someone.

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SQL Server’s Binary Collations

I was reading up on database engine Always Encrypted feature while preparing for 70-473 exam, and bump into these binary collations which I somehow never heard of before.

While configure Always Encrypted one of the choices you have to made is whether to use Deterministic or Randomized encryption (and you have to know the differences very well for the exam). One of the caveats when using Deterministic encryption is that it have to use a column collation with a binary2 sort order for character columns. More specifically documentation states that: Deterministic encryption requires a column to have one of the binary2 collations. If you will be using SSMS Encrypt Columns wizard it will be converting your column collation into binary2 case sensitive collation.

These statement required me to investigate the topic of binary collation a little bit.

First of all you may have different collation settings on a SQL Server instance level (i.e. on its system databases) on your databases and on specific columns and expression level.

To list all the collations available on your instance of SQL Server you can issue the following SQL statement:

On Azure SQL Database you will get back 3955 rows or possible collations. Understanding collation requires you to understand set of related terms, such as Collation, Locale, Code page, Sort order.  You should also know  that there are three major sets of collations available to you:

  • Windows collations
  • Binary collations
  • SQL Server collations

These collation groups sort data differently. In the past my standard answer/explanation about Windows VS SQL collation was that Windows one is more frequently updated, more compatible and hence more preferable over SQL one. Technically speaking it is more about how sorting works, but as per MSFT documentation: “SQL Server supports supports a limited number (<80) of collations called SQL Server collations which were developed before SQL Server supported Windows collations. SQL Server collations are still supported for backward compatibility, but should not be used for new development work.” So what I was saying/writing seems to be correct.

I won’t be covering all the details and differences related to these sets of collations as I only want to focus here on Binary collations which are requirement for Always Encrypted Deterministic encryption.

Binary collations sort data based on the sequence of coded values that are defined by the locale and data type. They are case sensitive. A binary collation in SQL Server defines the locale and the ANSI code page that is used. This enforces a binary sort order. Because they are relatively simple, binary collations help improve application performance. For non-Unicode data types, data comparisons are based on the code points that are defined in the ANSI code page. For Unicode data types, data comparisons are based on the Unicode code points. For binary collations on Unicode data types, the locale is not considered in data sorts. For example, Latin_1_General_BIN and Japanese_BIN yield identical sorting results when they are used on Unicode data.

There are two types of binary collations in SQL Server; the older BIN collations and the newer BIN2 collations. In a BIN2 collation all characters are sorted according to their code points. In a BIN collation only the first character is sorted according to the code point, and remaining characters are sorted according to their byte values. (Because the Intel platform is a little endian architecture, Unicode code characters are always stored byte-swapped.)

So for  Always Encrypted Deterministic encryption any of the collations returned by the query below will do:

This leaves you with 133 collations to choose from 🙂 Generally speaking BIN and BIN2 collations use different sorting algorithms and BIN2 is more preferable in general, not only for Always Encrypted Deterministic encryption columns. Another interesting question is why we have BIN/BIN2 collations for different languages? Like Arabic_BIN2, French_BIN2 etc. The reason is that each of those uses different code page for encoding the characters sorting in the varchar type so linguistic collation type is very important and comes into play only for varchar data as this will be sorted based on the language selected (this is not applicable to nvarchar where it has no difference).

All collations which are not binary collation are linguistic collations. For example, Latin1_General_CI_AS is a linguistic collation and it uses a sorting algorithm compatible with several of English language and many Western European languages. Please don’t be confused by the name of Latin1_General, as it actually can sort all Unicode characters defined in Unicode 3.2 characters set and it can also sort many other languages correctly as well (if the language has no sorting conflict with the latin1_general sorting rule).

Binary collations have better performance than linguistic collations, and that is the main advantage of using then. A binary collation is always case sensitive and accent sensitive. BIN2 collation is generally more preferable than BIN collation.

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SQL Script to switch all currently RO databases to RW mode

I was doing some testing of K2 databases consolidation process which required me to re-run database consolidation process more than once to re-try it. Unfortunately K2 Database Consolidation Tool leaves all databases in read-only mode if something fails during consolidation process. If you remember K2 used to have 14 separate data bases prior to consolidated DB was introduced (see picture below).

Typing 14 statements manually to bring all these database to read-write mode is a bit time consuming so I came up with the following script:

Essentially it will select all databases currently in RO state and will output bunch of statements to bring all of them to RW state as an output:

Just copy-paste this script output into new query window of SSMS and press F5 🙂

It may be useful for you once in a while (and if not for this specific use case, then as an example of generating some repetitive statements which contain select statement results inside).

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SQL Server: new instance installation frozen on “SqlEngineConfigAction_install_startup_Cpu64” step

I was installing additional new instance of SQL Server 2012 on a machine where other instance was installed earlier. In the process I run into the problem where Setup wuzard just frozen on about 99% on SqlEngineConfigAction_install_startup_Cpu64 step without flagging any errors and making no progress for hours, so that Setup window looks like that all the time:

I realized that I’ve seen it before but not made any efforts to fix it beyond starting process from scratch. This time I did some googling and found that there may be quite a few reasons for this problem, for example see this blog post: “Your SQL Server Setup may hang forever when it’s almost at the 99 %!” on MSDN Blogs. I tried a few suggestion with no luck but in the process I’ve noticed that Windows service for my new named instance has been already created but frozen in “Starting” state, so killing and restarting it manually revived SQL Setup Manager and it completed installation process with flying colors in a minute after this. So it seems SQL Setup Manager just endlessly waits for service started confirmation or something like this without any time out in place… Anyhow I’m just taking a note of my fix in case somebody else or myself run into this again.

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PS script to get SQL version from BAK file

Quite unpleasant thing about MS SQL Server database backup files it that you can’t restore them on an older version of SQL Server (it seems that even if you really want to create such BAK file it is not possible), moreover this is valid not only for major versions but also for things like R2, meaning you can’t restore BAK file created in SQL Server 2008 R2 on SQL Server 2008 Server (non-R2).

Just to save my time trying to restore BAK files against wrong versions of SQL Server I created this script:

It will allow you to retrieve SQL version from BAK file headers and compare it with your server SQL version. Specify path to your BAK file and check the output – if BAK file SQL version is newer that your server version then BAK file can’t be restored on this server. Sample script output can be found below:

It tells you that backup was taken on SQL Server 2012 SP3, while you run SQL Server 2012 SP2. Once you install SP3 for SQL Server script output will change to this:

Once two numbers match (or your SQL Server version number is higher than BAK file SQL version number) you are ready for backup restore 🙂 I’ve also added to this script comparison and output of its result, along with prompt for BAK file name and location:

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