Database Administrators Stack Exchange
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Questions tagged [checksum]

33 questions
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1 answer

How do data checksums interact with streaming replication?

Data checksums are a new feature introduced in 9.3, and: there is a new GUC parameter "ignore_checksum_failure" which will force PostgreSQL to continue processing a transaction even if corruption is detected In the event of a checksum failure on a…
Jack Douglas
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Null Values in a CASE statement

I am playing around with some stuff in SSMS to learn a little more as I study for my 70-461 exam and I came across a little hangup. I am trying to create a table to play around with so I don't have to alter/delete any of the already created tables…
user2921015
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How do pages get updated checksum when switching page verification mode from torn page to checksum?

Have an older but large db (6tb on the san) that still has its page verification option set to TORN_PAGE_DETECTION. How do you apply the new checksum to all existing pages when changing page verification to checksum mode? Is there any big overhead…
user2368632
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How to Resolve Corruption Detected by BACKUP WITH CHECKSUM, But NOT DBCC CHECKDB?

Recently, I was asked to refresh a couple of databases on a test server from production. Always wanting to follow best practices, I performed the backup using the WITH CHECKSUM option, and eventually got the following error: Msg 3043, Level 16,…
Hercule Poirot
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1 answer

What are the performance implications of using checksums vs change tracking for SQL Server

Back in the day, an implementation with checksum_agg was made to check if "something changed" in a table in a SQL Server table, to then make updates in another database. The users want to get the changes across between the systems quickly, so the…
Ola Eldøy
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2 answers

Mysql checksum for master-slave replication returning different values, despite being identical

I've set up a master slave replication in mysql and to make sure that I know if the data starts getting out of sync I created a script that: Locks both databases on both servers. Prints the checksums of all the tables to a text file. Copy's the…
Andreas Larsson
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Does enabling backup compression in a Back Up Database Task enable checksums, no matter what setting you pick for them?

Observations The documentation says To enable backup checksums in a BACKUP (Transact-SQL) statement, specify the WITH CHECKSUM option. To disable backup checksums, specify the WITH NO_CHECKSUM option. This is the default behavior, except for a…
J. Mini
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What is the best way to divide data for random groups?

I would like to have persisted column which will randomly group data for 32 groups according to one of varchar key column in table. My idea was: SELECT ABS(CAST(HASHBYTES('MD5',[keyColumnFromTable]) AS bigint) % 31) Questions: There is any better…
axdna
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Impacts of a change to the Page Verify option

There's no doubt about importance of doing regular integrity checks on production databases. I'm testing the impact of changing the maintenance plans and changing how databases are backed up. First of all, it is necessary to activate the "checksum"…
Gio
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How to check if backups are reliable?

I generally have to restore databases to different servers after important data imports or other important and delicate database operations. I need to be sure that my backups up to that point in time or transaction mark are reliable. I don't have…
Marcello Miorelli
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Will I be notified that BACKUP encountered a CHECKSUM error if I use CONTINUE_AFTER_ERROR?

I am in the process of adding the WITH CHECKSUM flag on our daily SQL backups, as part of an effort to better ensure data integrity. I definitely want to know if a checksum error is ever encountered, but I also don't want my job to stop dead in the…
BradC
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Is there any function like checksum in Oracle

I need to calculate the checksum of some columns. The built-in function checksum is used to calculate the checksum in Microsoft SQL Server. Is there any built-in function checksum in Oracle?
Noah
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How to verify (CHECKSUM or MD5) dataset you received over a network?

I will remotely query mysql database and I want to check that the received dataset matches the table in the host computer. How do you do that? I am fairly new to sql database. I know of Checksum and md5, but how do you use them to verify the…
ThN
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How to guarantee rows order

I'm trying to implement a methodology to check the integrity of a restored database. It goes as following: Create a snapshot of the database. Gather various metadata: On disk used space. Name of tables. Number of rows in each tables.…
Spack
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PostgreSQL equivalent to checksum table

What would be the fastest operation of checksum table, which returns the same value in MySQL and in Postgres if there is the same dataset in tables? It could be a function, or just an equivalent of MySQL's checksum in Postgres. Looking for a way to…
Sławomir Lenart
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