Summit Old, Summit New, Summit Borrowed…

PASS Summit is coming up, and I thought I’d post a few things.

Summit Old…

At the PASS Summit, you will get the chance to hear presentations by the SQL Server establishment. Just about every big name in the SQL Server world is a regular at the PASS Summit, so you will get to hear and meet people like Kalen Delaney (@sqlqueen) (who just recently got awarded MVP status for the 20th year running), and from all around the world such as the UK’s Chris Webb (@technitrain) or Pinal Dave (@pinaldave) from India. Almost all the household names in SQL Server will be there, including a large contingent from Microsoft. The PASS Summit is by far the best place to meet the legends of SQL Server. And they’re not all old. Some are, but most of them are younger than you might think.

…Summit New…

The hottest topics are often about the newest technologies (such as SQL Server 2012). But you will almost certainly learn new stuff about older versions too. But that’s not what I wanted to pick on for this point.

There are many new speakers at every PASS Summit, and content that has not been covered in other places. This year, for example, LobsterPot’s Roger Noble (@roger_noble) is giving a presentation for the first time. He’s a regular around the Australian circuit, but this is his first time presenting to a US audience. New Zealand’s Paul White (@sql_kiwi) is attending his first PASS Summit, and will be giving over four hours of incredibly deep stuff that has never been presented anywhere in the US before (I can’t say the world, because he did present similar material in Adelaide earlier in the year).

…Summit Borrowed…

No, I’m not talking about plagiarism – the talks you’ll hear are all their own work.

But you will get a lot of stuff you’ll be able to take back and apply at work. The PASS Summit sessions are not full of sales-pitches, telling you about how great things could be if only you’d buy some third-party vendor product. It’s simply not that kind of conference, and PASS doesn’t allow that kind of talk to take place. Instead, you’ll be taught techniques, and be able to download scripts and slides to let you perform that magic back at work when you get home. You will definitely find plenty of ideas to borrow at the PASS Summit.

…Summit Blue

Yeah – and there’s karaoke. Blue – Jason – SQL Karaoke – YouTube

Calling home, receiving calls and smartphone data from the US

I got asked about calling home from the US, by someone going to the PASS Summit. I found myself thinking “there should be a blog post about this”…

The easiest way to phone home is Skype – no question. Use WiFi, and if you’re calling someone who has Skype on their phone at the other end, it’s free. Even if they don’t, it’s still pretty good price-wise. The PASS Summit conference centre has good WiFI, as do the hotels, and plenty of other places (like Starbucks).

But if you’re used to having data all the time, particularly when you’re walking from one place to another, then you’ll want a sim card. This also lets you receive calls more easily, not just solving your data problem. You’ll need to make sure your phone isn’t locked to your local network – get that sorted before you leave.

It’s no trouble to drop by a T-mobile or AT&T store and getting a prepaid sim. You can’t get one from the airport, but if the PASS Summit is your first stop, there’s a T-mobile store on 6th in Seattle between Pine & Pike, so you can see it from the Sheraton hotel if that’s where you’re staying. AT&T isn’t far away either.

But – there’s an extra step that you should be aware of.

If you talk to one of these US telcos, you’ll probably (hopefully I’m wrong, but this is how it was for me recently) be told that their prepaid sims don’t work in smartphones. And they’re right – the APN gets detected and stops the data from working. But luckily, Apple (and others) have provided information about how to change the APN, which has been used by a company based in New Zealand to let you get your phone working.

Basically, you send your phone browser to http://unlockit.co.nz and follow the prompts. But do this from a WiFi place somewhere, because you won’t have data access until after you’ve sorted this out…

Oh, and if you get a prepaid sim with “unlimited data”, you will still need to get a Data Feature for it.

And just for the record – this is WAY easier if you’re going to the UK. I dropped into a T-mobile shop there, and bought a prepaid sim card for five quid, which gave me 250MB data and some (but not much) call credit. In Australia it’s even easier, because you can buy data-enabled sim cards that work in smartphones from the airport when you arrive.

I think having access to data really helps you feel at home in a different place. It means you can pull up maps, see what your friends are doing, and more. Hopefully this post helps, but feel free to post comments with extra information if you have it.

@rob_farley

When someone deletes a shared data source in SSRS

SQL Server Reporting Services plays nicely. You can have things in the catalogue that get shared. You can have Reports that have Links, Datasets that can be used across different reports, and Data Sources that can be used in a variety of ways too.

So if you find that someone has deleted a shared data source, you potentially have a bit of a horror story going on. And this works for this month’s T-SQL Tuesday theme, hosted by Nick Haslam, who wants to hear about horror stories.TSQL2sDay150x150 I don’t write about LobsterPot client horror stories, so I’m writing about a situation that a fellow MVP friend asked me about recently instead.

The best thing to do is to grab a recent backup of the ReportServer database, restore it somewhere, and figure out what’s changed. But of course, this isn’t always possible.

And it’s much nicer to help someone with this kind of thing, rather than to be trying to fix it yourself when you’ve just deleted the wrong data source. Unfortunately, it lets you delete data sources, without trying to scream that the data source is shared across over 400 reports in over 100 folders, as was the case for my friend’s colleague.

So, suddenly there’s a big problem – lots of reports are failing, and the time to turn it around is small. You probably know which data source has been deleted, but getting the shared data source back isn’t the hard part (that’s just a connection string really). The nasty bit is all the re-mapping, to get those 400 reports working again.

I know from exploring this kind of stuff in the past that the ReportServer database (using its default name) has a table called dbo.Catalog to represent the catalogue, and that Reports are stored here. However, the information about what data sources these deployed reports are configured to use is stored in a different table, dbo.DataSource. You could be forgiven for thinking that shared data sources would live in this table, but they don’t – they’re catalogue items just like the reports. Let’s have a look at the structure of these two tables (although if you’re reading this because you have a disaster, feel free to skim past).

Frustratingly, there doesn’t seem to be a Books Online page for this information, sorry about that. I’m also not going to look at all the columns, just ones that I find interesting enough to mention, and that are related to the problem at hand. These fields are consistent all the way through to SQL Server 2012 – there doesn’t seem to have been any changes here for quite a while.

dbo.Catalog

The Primary Key is ItemID. It’s a uniqueidentifier. I’m not going to comment any more on that. A minor nice point about using GUIDs in unfamiliar databases is that you can more easily figure out what’s what. But foreign keys are for that too…

Path, Name and ParentID tell you where in the folder structure the item lives. Path isn’t actually required – you could’ve done recursive queries to get there. But as that would be quite painful, I’m more than happy for the Path column to be there. Path contains the Name as well, incidentally.

Type tells you what kind of item it is. Some examples are 1 for a folder and 2 a report. 4 is linked reports, 5 is a data source, 6 is a report model. I forget the others for now (but feel free to put a comment giving the full list if you know it).

Content is an image field, remembering that image doesn’t necessarily store images – these days we’d rather use varbinary(max), but even in SQL Server 2012, this field is still image. It stores the actual item definition in binary form, whether it’s actually an image, a report, whatever.

LinkSourceID is used for Linked Reports, and has a self-referencing foreign key (allowing NULL, of course) back to ItemID.

Parameter is an ntext field containing XML for the parameters of the report. Not sure why this couldn’t be a separate table, but I guess that’s just the way it goes. This field gets changed when the default parameters get changed in Report Manager.

There is nothing in dbo.Catalog that describes the actual data sources that the report uses. The default data sources would be part of the Content field, as they are defined in the RDL, but when you deploy reports, you typically choose to NOT replace the data sources. Anyway, they’re not in this table. Maybe it was already considered a bit wide to throw in another ntext field, I’m not sure. They’re in dbo.DataSource instead.

dbo.DataSource

The Primary key is DSID. Yes it’s a uniqueidentifier…

ItemID is a foreign key reference back to dbo.Catalog

Fields such as ConnectionString, Prompt, UserName and Password do what they say on the tin, storing information about how to connect to the particular source in question.

Link is a uniqueidentifier, which refers back to dbo.Catalog. This is used when a data source within a report refers back to a shared data source, rather than embedding the connection information itself. You’d think this should be enforced by foreign key, but it’s not. It does allow NULLs though.

Flags this is an int, and I’ll come back to this.

When a Data Source gets deleted out of dbo.Catalog, you might assume that it would be disallowed if there are references to it from dbo.DataSource. Well, you’d be wrong. And not because of the lack of a foreign key either.

Deleting anything from the catalogue is done by calling a stored procedure called dbo.DeleteObject. You can look at the definition in there – it feels very much like the kind of Delete stored procedures that many people write, the kind of thing that means they don’t need to worry about allowing cascading deletes with foreign keys – because the stored procedure does the lot.

Except that it doesn’t quite do that.

If it deleted everything on a cascading delete, we’d’ve lost all the data sources as configured in dbo.DataSource, and that would be bad. This is fine if the ItemID from dbo.DataSource hooks in – if the report is being deleted. But if a shared data source is being deleted, you don’t want to lose the existence of the data source from the report.

So it sets it to NULL, and it marks it as invalid.

We see this code in that stored procedure.

Unfortunately there’s no semi-colon on the end (but I’d rather they fix the ntext and image types first), and don’t get me started about using the table name in the UPDATE clause (it should use the alias DS). But there is a nice comment about what’s going on with the Flags field.

What I’d LIKE it to do would be to set the connection information to a report-embedded copy of the connection information that’s in the shared data source, the one that’s about to be deleted. I understand that this would cause someone to lose the benefit of having the data sources configured in a central point, but I’d say that’s probably still slightly better than LOSING THE INFORMATION COMPLETELY. Sorry, rant over. I should log a Connect item – I’ll put that on my todo list.

So it sets the Link field to NULL, and marks the Flags to tell you they’re broken. So this is your clue to fixing it.

A bitwise AND with 0x7FFFFFFD is basically stripping out the ‘2’ bit from a number. So numbers like 2, 3, 6, 7, 10, 11, etc, whose binary representation ends in either 11 or 10 get turned into 0, 1, 4, 5, 8, 9, etc. We can test for it using a WHERE clause that matches the SET clause we’ve just used. I’d also recommend checking for Link being NULL and also having no ConnectionString. And join back to dbo.Catalog to get the path (including the name) of broken reports are – in case you get a surprise from a different data source being broken in the past.

When I just ran this on my own machine, having deleted a data source to check my code, I noticed a Report Model in the list as well – so if you had thought it was just going to be reports that were broken, you’d be forgetting something.

So to fix those reports, get your new data source created in the catalogue, and then find its ItemID by querying Catalog, using Path and Name to find it.

And then use this value to fix them up. To fix the Flags field, just add 2. I prefer to use bitwise OR which should do the same. Use the OUTPUT clause to get a copy of the DSIDs of the ones you’re changing, just in case you need to revert something later after testing (doing it all in a transaction won’t help, because you’ll just lock out the table, stopping you from testing anything).

But please be careful. Your mileage may vary. And there’s no reason why 400-odd broken reports needs to be quite the nightmare that it could be. Really, it should be less than five minutes.

@rob_farley