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A bizarre situation - SQL query finds no records when record is present.
I am trying to troubleshoot a bizarre situation, and looking for either an explanation of the cause, or assistance in determining the cause. The situation is esoteric (to say the least), so I'll need to paint a picture. I am using SQL 2019 Enterprise for testing. Our database has Allow Snapshot Isolation set to true, and the Is Read Committed Snapshot On is also true. We have a table called T_App_View, with essentially these important fields (plus some audit fields not shown): CREATE TABLE T_App_View ( C_Id int not null, C_Type varchar( 20 ) not null, C_Entity varchar( 250 ) not null, C_Specialisation varchar( 250 ) null, CONSTRAINT APPVIEW_PKC PRIMARY KEY NONCLUSTERED( C_Id ) ) We have an index on (Type, Entity, Specialisation): create unique index APPVIEW_I01 on T_App_View( C_Type, C_Entity, C_Specialisation ) And from a historical hangover we have a view against the table that is used for queries: CREATE VIEW dbo.VS_App_View AS SELECT * FROM dbo.T_App_View WITH CHECK OPTION The table is used to define "UI views" for our application, and contains about 1000 records. As part of commissioning a new database, we use a tool to load data into this table, and then the data basically sits there unchanged. Each time the tool is run it deletes any old data in the table, before populating the new data. The tool deletes the old data row-by-row rather than using a truncate table statement or similar. When our web tier is asked to provide the "definition" of a view, it performs a query on VS_App_View using the three compound key components of Type, Entity, and Specialisation. A dynamic cursor is used (a historical hangover from many years ago). A typical query would look similar to this: SELECT appview.C_Id, appview.C_Entity_Id, appview.C_Specialisation, appview.C_View_Type FROM dbo.VS_App_View appview WHERE appview.C_View_Type = 'DETAIL' AND appview.C_Entity_Id = 'a' AND appview.C_Specialisation = 'Finance' We are using the standard isolation level of Read Committed (which means Read Committed Snapshot in reality). Notice the select statement is not using an option of READCOMMITTED in the query. The fun part Sometimes when we do a lookup in SQL Server, the above query finds no matching records. This bug is very evasive, we cannot reproduce it, and it appears maybe once or twice a month, and other months not at all. It is not limited to specific key values, it just appears to happen randomly (or the pattern is obscure enough that we cannot yet see it). Our QA team experienced the find failure the other day and one of our developers jumped into SSMS and ran the query manually and sure enough it came back with no records found. And now the bizarre bit: The developer ran the query directly against the T_App_View table, and the record appeared. He then re-ran the query against the View, and the record appeared. We have the Query Store enabled for this database and I can see two plans matching the above query (one for a null specialisation, and one for a non-null specialisation). The query plans look odd (due to the dynamic cursor presumably) because even though the index guarantees a maximum of one matching record, the query plan still shows a temporary table being constructed along with a clustered index for that table. I feel like I am reasonably proficient in SQL Server but this one has me stumped. ChatGpt suggested it is a query plan issue, but I'm skeptical as I've never heard of a query plan not finding a record. I've only experienced query plan issues in terms of performance impacts. Has anyone ever come across such a situation? Is Snapshot Isolation part of the problem here, or database statistics, or the fact we are deleting an entire table of records individually and then repopulating them (resulting in bad statistics)? Should we have used WITH( READCOMMITTEDLOCK ) for this query perhaps? Any suggestions on how to troubleshoot effectively, as in what to look at and for? Thanks in advance for any help.
Documentation contradictory
Hi, ALL, Page https://learn.microsoft.com/en-us/sql/t-sql/statements/create-database-transact-sql?view=sql-server-ver17&tabs=sqlpool states [quote] SIZE, MAXSIZE, and FILEGROWTH parameters can be set when a UNC path is specified for the file. [/quote] However later on that same page it states [quote] SIZE can't be specified when the os_file_name is specified as a UNC path. [/quote] I think those 2 sentences contradicts each other.....
Kerberos double hop delegation on SQL Linked Server fails on AG listener after RC4 disablement
Environment 3 Node- SQL Server 2022 with Availability Group Windows Server 2022 - Linked Server configured with Kerberos delegation (double-hop scenario) - RC4 encryption recently disabled via GPO The Problem After disabling RC4 in the domain (not sure of this root cause), Kerberos delegation through a Linked Server stopped working — but only when connecting via the **AG listener name**. Connecting via the **node name** works fine. I try to migrate my service account to gMSA and I've recreate all SPN and all delegation for the new account, but the issue is the same: Authentication works if the linked server us the node name, if it use the Listener AG name the connection fail with ------------------------------ Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'. (Microsoft SQL Server, Error: 18456) Connection Id 6d654295-0538-4837-b900-ff65c9e86ee9 at 2026-04-29 11:59:25Z I Confirmed via Kerberos event logging (Event ID 4769 on DC)** On a healthy request (node name), ticket encryption type is `0x12` (AES256). - Confirmed SPN registration with `setspn -L` - Verified Kerberos events on the DC (4768/4769) - Confirmed forwardable flag (`0x40000000`) is present in ticket options — delegation is active - Confirmed pre-auth and session encryption are both `0x12` (AES256) for the working path set `msDS-SupportedEncryptionTypes = AES128+AES256` on the SQL service account and resetting its password rotete kdc key Are there any additional steps needed on the Linked Server or constrained delegation configuration side after the service account change? Any guidance appreciated. Thanks.
MS ODBC and OLE DB failed
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Access to SQL Jobs
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Hello, I am trying to better understand the internal workflow of GitHub Copilot in SSMS 22, especially for database-specific questions. From the product descriptions, it seems that Copilot can use the context of the currently connected database, such as schema, tables, columns, and possibly other metadata, when answering questions or generating T-SQL. However, I could not find clear official documentation about the actual sequence of operations. My main questions are: Before generating a response, does Copilot first collect database context/metadata from the active connection and then send that context to the LLM as grounding information? Or does it first use the LLM to interpret the user’s request, decide what information is needed, and then retrieve database metadata before generating the final answer? In some explanations, I have seen the phrase "Core SQL Copilot Infrastructure", but I cannot find any official documentation for that term. Is this an official component name? If so, what does it specifically refer to in the SSMS Copilot architecture? When Copilot answers schema-related or data-related questions, what information is retrieved automatically from the connected database, and is any SQL executed as part of that process? Is there any official architectural documentation that explains: context collection, prompt grounding, LLM invocation order, and whether query execution can occur before the final response is generated? I am asking because I want to understand the feature from both an architecture and data governance/security perspective. Any clarification from the product team or documentation links would be greatly appreciated. Thank you.Unable to install SQL Server 2022 Express (installer glitch + SSMS error)
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