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Category: Bugs

Notes on DBATools’s Get-DecryptedObject

Sean Gallardy explains an issue:

Let me start off by saying that DBATools is a great tool that is immensely helpful to the community, if you haven’t heard about it or tried it, please give it a shot! I personally believe that the SQL Server community is truly the best out there, with so many people helping each other and developing great, free, tools that benefit all. Having said that, I’ve been asked quite a few times to look into a “SQL Server Bug” decrypting data.

This is not an issue with SQL Server nor is it a bug/feature/whatever. It is, in fact, a bug in the source material for DBATools.

Read the whole thing.

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Tracking Database Errors with Extended Events

Eitan Blumin is watching you:

But interestingly enough – we would be getting an added benefit here. Even if there is no SQL injection attack, it’s still possible that such errors would be raised by the application – simply due to bugs.

Furthermore, these errors in the database may be happening without anyone even noticing! How could that be, you ask? Well, it could be due to bad error handling that “swallows” the error entirely, or because the errors are logged but no one is bothering to look at the logs, or maybe because the errors are caught but an undetailed error message is logged/displayed to the user (I can’t even count how many times I encountered “general database error” messages in applications), or because the developers simply decided to mark this as a “known issue” that they didn’t bother to fix and they didn’t think to ask their DBA about it… The reasons are numerous and varying.

Click through for the scripts. I had built something similar about a decade ago, a simple WPF app which watched for errors. I messaged him with something like “You missed a comma in that IN clause” and I saw him pop up from his cubicle and look around, trying to figure out how I could peek over his shoulder and see the query.

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Debugging Code in R

Cosima Meyer explains how debugging works in R with RStudio:

Three basic commands in RStudio let you do the debugging: debug(function_name)browser(), and undebug(function_name).

With debug(function_name) you start the debugging of your function – it’s basically like a mole that digs in. When you’re in debug mode, you can also call the objects in your function.

Read the whole thing to learn the power of debugging beyond the print() statement. H/T R-Bloggers.

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Triggering Dumps for Specific Errors and States

Bob Dorr has a plan:

I had an inquiry about dbcc dumptrigger today and realized that state filtering was added to dbcc dumptrigger but not well known.

You can collect a process dump (SQL Dumper) when a specific error occurs using XEvent (error_reported/ex_raise2 events with dump capture action) or dbcc dumptrigger.

The common use of dbcc dumptrigger is: dbcc dumptrigger(‘set’, 208) to produce a dump when error 208 is encountered.

This is pretty useful, especially if you’re troubleshooting a bug in the database engine.

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Breaking Changes in Azure Data Explorer Window Functions

Gabi Lehner announces an upcoming bugfix:

This is a Breaking change when using window functions inside partition operator sub-query scope.

Window functions require a serialized/ordered input.

There is a bug in Azure Data Explorer logic that allows using window functions inside the partition operator when the ordering is performed outside the partition query scope like this:

Click through for what currently works as well as its future replacement.

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823/824 Alerts with SQL Server and VMware

David Klee loops us in on a tricky-to-catch problem:

We’ve been tracking a weird state with SQL Server virtual machines on VMware and possible warnings on database corruption while VM backups are running, largely centered around (but not isolated to) the tempdb database.

TLDR: We’ve now got a VMware KB article on this situation that you and your VM admins should read if you hit the condition and fall into the specifics listed below. Reference VMware KB 88201 for more details.

Read on for David’s thoughts and what to do if you hit this problem.


Error Calling SQLSetDescRec via PolyBase

Nathan Schoenack troubleshoots an error:

When trying to query an external table created for a generic ODBC external data source, the following error can be observed:

Message 7320, level 16, state 110, line 87

Unable to execute query “Remote Query” against OLE DB provider “MSOLEDBSQL” on link server “(null)”. 105082; Generic ODBC error: OdbcBufferReader.ReadBuffer, error in OdbcReadBuffer: SqlState: IM001, NativeError: 0, ‘Error calling: SQLSetDescRec(this->GetHdesc(), (SQLSMALLINT)column->idxServerCol, (SQLSMALLINT)column->odbcReadType, 0, column->valueLength, (SQLSMALLINT)column->precision, (SQLSMALLINT)column->scale, (SQLPOINTER)(pBuffer + column->valueOffset), (SQLLEN *)indPtr, (SQLLEN *)indPtr), SQL return code: -1 | SQL Error Info: Error <1>: ErrorMsg: [Microsoft][ODBC Driver Manager] The driver does not support this function. | Error calling: pReadConn->ReadBuffer(pBuffer, bufferOffset, bufferLength, pBytesRead, pRowsRead) | state: FFFF, number: 239, active connections: 9’, Connection String: Dsn={DSN Name};Driver={Driver Name};uid=root;server=xxxxx;port=xxxx;database=xxxx.

Read on for a viable workaround.

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Capturing a Call Stack without a Dump

Bob Dorr shows off Arvind’s SQL Call Stack Resolver:

Some outputs, such as the XEvent call stack action output the raw stack frame information and require a rebase to loaded module information in order to symbolize.   The security feature for random address virtualization loads images at different addresses each time the image is loaded.   This requires the module base address and the raw address in order to calculate the relative virtual address for symbolization.

Click through for more information.

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