Pro SQL Server Internals
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A: It's easy to do that on a single server. I believe it is theoretically possible to do that across two different servers, especially if you are using a query store. However, I believe it would be next to impossible in practice. That's because even if we have objects all with the same name, they may not have the same object IDs. So, there could easily be differences in the plans at a binary level.
In my previous article, I talked about SQL server diagnostics, including the various options that SQL Server has for reusing a query plan. We looked at three types of query plans: adhoc, prepared, and procedure. I ended the discussion with a look at an inappropriate reuse of a plan, which can happen when SQL Server applies parameter sniffing in the wrong situations. If a plan is based on an initial value that causes the optimizer to generate a plan appropriate for that value, and then the same plan is used for a different value, the plan may no longer be optimal.
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What I expect is happening under the hood (I am not a SQL Server internals expert, so the following is all speculation) is SQL sees the columns being added with NULL being allowed to be in the column so there is no data changes. Since no data is changed (only metadata), it sees no need to update things on disk at this time. Likely it is doing this for performance reasons. Once the data is modified, it needs to persist everything in there to disk as the change on the row MAY result in any of the columns having their data changed. All of the variable length columns would use 1 additional byte of space (for the NULL marker) and all fixed length columns would use up their allocated disk space requirements (such as nullable CHAR(10) using 11 (ish) bytes per row).
The above is all just my opinion on what you should do. As with all advice you find on a random internet forum - you shouldn't blindly follow it. Always test on a test server to see if there is negative side effects before making changes to live!I recommend you NEVER run \"random code\" you found online on any system you care about UNLESS you understand and can verify the code OR you don't care if the code trashes your system.
I am not an internals expert, but I believe that if a table has any nullable columns it always stores a 'null bitmap' for each row to indicate the null values. So if you have a table with no nullable columns, and then you add nullable columns, the table will grow due to the creation of the null bitmap.
I don't think that the server is creating new column to an existing table as sparse columns. Creating column as sparse columns has a big effect on the storage and there are specific scenarios that it will be beneficial. In most scenarios it will not be beneficial, so I don't think that Microsoft will create sparse columns as default behavior when we are adding new columns to an existing tables.
From what I know when you add a new column that is nullable or has a default, the column will not be added to each row. Instead it will be added to the table's metadata as a runtime constant. The data will be moved to the row when the row is updated (even if it is updated with the same data that exists in the runtime constant or the column is not referenced by the update statement). It will also be moved to the table if you rebuild the table. You can read more about it in this link - -us/sql/t-sql/statements/alter-table-transact-sqlview=sql-server-ver15 (under the section \"Adding not null columns as an online operation\").
Pro SQL Server Internals is a book for developers and database administrators, and it covers multiple SQL Server versions starting with SQL Server 2005 and going all the way up to the recently released SQL Server 2016. The book provides a solid road map for understanding the depth and power of the SQL Server database server and teaches how to get the most from the platform and keep your databases running at the level needed to support your business. The book: - Provides detailed knowledge of new SQL Server 2016 features and enhancements - Includes revamped coverage of columnstore indexes and In-Memory OLTP - Covers indexing and transaction strategies - Shows how various database objects and technologies are implemented internally, and when they should or should not be used - Demonstrates how SQL Server executes queries and works with data and transaction log
I need to expose our SQL Server 2008 database for an access from a asp.net web application.This is a new task for me, so I would like to know what basic security requirements are there for configuring software and hardware components of web server and DB Server.
2 Failover recovery observed in Hewlett Packard Enterprise internal lab testing. The system was based on an HPE ProLiant DL560 Gen10 server with RHEL 7.3 running HPE Serviceguard 12.10.00 configuration dependent, excluding cluster reformation time. 59ce067264