aveanna.blogg.se - Sql server deadlock 256

#SQL SERVER DEADLOCK 256 HOW TO#
#SQL SERVER DEADLOCK 256 CODE#

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON To be honest, I don't know enough to know if I should alter that.Īnd here is the non-clustered index that's also on the table: CREATE NONCLUSTERED INDEX ON. ADD CONSTRAINT DEFAULT ('') FOR ĪLTER TABLE. ADD CONSTRAINT DEFAULT ((0)) FOR ĪLTER TABLE. ADD CONSTRAINT DEFAULT (getdate()) FOR ĪLTER TABLE. )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON ĪLTER TABLE. (100) NOT NULL,ĬONSTRAINT PRIMARY KEY CLUSTERED Here is the table's schema, generated from a create script: SET ANSI_NULLS ON The number of rows can vary, but the high end might be something like 4,000. String destColumn = columnNames.Single(x => x.Equals(column.ColumnName, StringComparison.OrdinalIgnoreCase)) ī(column.ColumnName, destColumn) Īwait bulkCopy.WriteToServerAsync(dataTableWithEnumStrings) įrom what I can tell, it looks like a page lock. The column mappings are case sensitive, so grab the destination column so we can use its casing. Add column mappings so we don't have to worry about order when adding new columns/properties.įoreach (DataColumn column in dataTableWithEnumStrings.Columns) Var dataTableWithEnumStrings = ConvertDataTableEnum(dataTable) Var dataTable = ToDataTable(histories, columnNames) Here is the bulk copy code: using (SqlBulkCopy bulkCopy = new SqlBulkCopy(sqlConnection, SqlBulkCopyOptions.Default, sqlTransaction))īulkCopy.DestinationTableName = destinationTableName Both the victim and blockers show the same SQL statements.

#SQL SERVER DEADLOCK 256 CODE#

This is the line of code that does the inserts: await bulkCopy.WriteToServerAsync(dataTableWithEnumStrings) Should it be possible for deadlocks to occur in this scenario? They are done within a transaction. And that table's PK is an identity column. The bulk inserts are inserting into the same table. But a colleague mentioned it shouldn't be possible with my setup. I think these simultaneous bulk inserts are the reason why the deadlock is occurring. The deadlock usually happens, but not always. Using a message bus, many subscribers can end up doing a bulk insert at roughly the same time.

SQL Server deadlock is a problem in which two sessions lock on a resource that the other session wants to access and vice versa.When analyzing a deadlock graph, it looks like the victim is a bulk insert, and the blockers are the same bulk insert.

Code language: SQL (Structured Query Language) ( sql ) Summary Transaction (Process ID 65) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. In our case, the deadlock victim is the process ID 65. Once a deadlock occurs, SQL Server will kill a deadlock victim. Here’s the sequence of statements that you need to execute from each session. Then, we’ll create two sessions to connect to the database. ) Code language: SQL (Structured Query Language) ( sql ) SET total = ( SELECT SUM(amount * ( 1 + tax)) INSERT INTO invoice_items ( id, invoice_id, item_name, amount, tax) INSERT INTO invoices (customer_id, total) Tax decimal( 4, 2) NOT NULL CHECK (tax >= 0),įOREIGN KEY (invoice_id) REFERENCES invoices ( id) Total decimal( 10, 2) NOT NULL DEFAULT 0 CHECK (total >= 0)Īmount decimal( 10, 2) NOT NULL CHECK (amount >= 0), In this example, we’ll first create the invoices and invoice_items tables: CREATE TABLE invoices ( Let’s take a look at an example of creating a deadlock. The session that is terminated by SQL Server is called a deadlock victim. At the same time, session two wants to access the invoices table but needs to wait for session two to complete.Īs the result, two sessions are waiting for each other until SQL Server proactively terminates one of them.

Third, session one wants to access the invoice_items table but needs to wait for session two complete.

Second, session two locks the invoice_items table and locks it.

First, session one accesses the invoices table and locks it.

In this picture, the invoices and invoice_items are tables. The following picture illustrates a deadlock in SQL Server: The first session has a lock on a resource that the other session wants to access, and vice versa. Introduction to the SQL Server deadlockĪ deadlock is a concurrency problem in which two sessions block the progress of each other.

#SQL SERVER DEADLOCK 256 HOW TO#

Summary: in this tutorial, you’ll learn about the SQL Server deadlock and how to simulate a deadlock.