The processes of creating a point in time copy of data.

learn more… | top users | synonyms

27
votes
4answers
7k views

Is it possible to quickly create/restore database snapshots with PostgreSQL?

First of all, I'm a developer, not a DBA or sysadmin; please be gentle :) I'm working on an application workflow where a single user action will trigger complex changes in the database - creating ...
11
votes
5answers
2k views

Backing up & restoring 10-20 SQL Server databases to a ~synchronous state?

I need to backup up 10-20 SQL Server 2008 R2 databases with sizes between 10-50 GB, while they are online and used simultaneously by a single enterprise app. I also need to restore them to a state ...
9
votes
1answer
2k views

EC2 - How to correctly back up PostgreSQL data?

Here is the setup: 1 small Amazon Linux (EBS-backed) EC2 instance with 3 additional volumes. This is both a web server and database server. One volume for code, one for the PostgreSQL (8.4) data ...
8
votes
2answers
771 views

Are SQL Server Database writes slower with Snapshot Isolation?

I have a lot of deadlocks going on in my system. I would like to use Snapshot Isolation to fix them, but my DBA has reserves about it. One of his concerns is that Snapshot Isolation slows down ...
8
votes
1answer
2k views

Does SQL Server Snapshot replication completely copy the data every time or does it issue deltas?

I am looking at snapshot replication between two servers. Here is what I have: 500GB database ~500MB nightly bcp loads ~50MB daily transactions I was asking other DBAs in the company about which ...
7
votes
3answers
1k views

What methods are available to create a snapshot of an oracle database for testing purposes?

I am new to databases and have just been assigned to work with Oracle. We want to create a snapshot of the database for testing purposes that will allow us to revert back once we're done. I'm a bit ...
7
votes
1answer
5k views

How can I query for existing database snapshots in SQL server?

I'm trying to create a t-sql query that can determine whether or not a given database has any database snapshots that were created from it. For example, if I were to create a snapshot like this: ...
7
votes
2answers
1k views

Advantage of using a database snapshot for reporting purposes

What is the performance advantage of using a snapshot of a database for reporting purposes? The way I see it, it would probably downgrade performance since for every write in the original database, ...
6
votes
3answers
1k views

SQL Server 2008 mirrored Database with manual failover, need reporting database

Our current setup is a principal database used in production with a manual failover mirrored database for HA. I need to setup a reporting database as well. What would be the best approach? Shall I ...
6
votes
3answers
2k views

Using SQL Snapshot Replication to refresh TEST databases from PRODUCTION. Why not?

What are the drawbacks and downsides? We want to schedule automatic nightly refreshes of 20 databases, approximately 1GB each, from the PRODUCTION server to the TEST server. We're setting up SQL ...
6
votes
2answers
532 views

Sql server snapshot isolation overhead when read_committed_snapshot is enabled

When SQL Server's read committed snapshot is on (and thus some amount of row versioning is necessary), is there any additional overhead caused merely by enabling snapshot isolation? Snapshot ...
6
votes
1answer
2k views

Remote queries at SNAPSHOT isolation level

I'm experimenting with snapshot isolation level. Whenever I try to access a linked server, I get an error: Remote access is not supported for transaction isolation level "SNAPSHOT" I wasn't able ...
5
votes
1answer
3k views

What is the proper way to backup MySQL database with rsnapshot?

I want to backup my website that contains both user uploaded images and data stored in MySQL database such that they are always consistent with each other in any particular point of time. While ...
5
votes
1answer
2k views

How can I determine the date of a snapshot in SQL Server 2008r2?

I am working on implementing an ETL process to load data into a warehouse. Part of this process is pulling data from our production server (Server P) to a staging server where the actual load into ...
5
votes
2answers
25k views

Why is my database stuck in the Restoring state?

I have some unit tests that manipulates data in a database. In order to guarantee that the database state is always the same throughout all the tests, we're trying restore a database snapshot at the ...
5
votes
2answers
908 views

Database stuck in restoring and snapshot unavailable [closed]

I tried to restore my database from a snapshot. This usually took around a minute to complete the last couple of times. When I did it today, it didn't complete for around 30 minutes and the spid was ...
4
votes
3answers
4k views

How to undo every change made to a database in a controlled environment?

I'm doing system testing of a product, and several tests are severely changing the data of a demo database. The data is quite complex to create queries which will undo the changes done by the tests; ...
4
votes
1answer
69 views

Get a listing of snapshot data files

I need to programmatically drop a database with all of its snapshots and then recreate the database and create a new snapshot. I'm having trouble locating where the snapshot files are located from ...
4
votes
1answer
1k views

Why are Stored Procedure schema changes not being replicated when using ”initialize with backup”?

In SQL Server I have set up transational replication using the "initialize with backup" option. Data is being replicated fine, as are schema changes to tables. However, schema changes to stored ...
3
votes
2answers
1k views

Excessive replication snapshot size causing failure

I am searching for an explanation of a replication snapshot being in excess of 5 times what we're predicting Following a replication failure we are attempting to reinitialise subscriptions with a new ...
3
votes
2answers
2k views

What is the best way to automatically create a snapshot of the table at the certain time?

I have running and quite loaded PostgreSQL server. I need to take snapshots of the certain tables at the certain time (midnight). Those tables are pretty loaded (a lot of updates and inserts). What ...
3
votes
2answers
248 views

Can PostgreSQL support integration test with some kind of throwaway overlay?

It's a common problem to write integration tests that include a database. If the test changes the database then it could effect other tests or the next run of itself. I know that I could wrap my test ...
3
votes
2answers
228 views

Why database snapshot creation is faster than normal database backups?

Could you tell me any reason why creation of database snapshot is faster than database normal database backups in MS SQL server
3
votes
1answer
121 views

How widespread is the adoption and usage of database snapshots?

After reading up on database snapshots, it seems that they are useful as a backup and quick restore method for small DDL and DML changes. Additionally they are useful for large scale dev/test ...
3
votes
2answers
145 views

Online index rebuild snapshot location and impact of filling index drive

My understanding of a rebuild index online operation is that the index will have a snapshot taken and the rebuild is started on the snapshot index. My question is where does the snapshot index ...
3
votes
1answer
528 views

Oracle Materialized View

I need your help with a issue on Oracle Materialized View. I created the Materialized View using the following command: CREATE MATERIALIZED VIEW SNAP_TEST TABLESPACE tbs NOCACHE LOGGING NOPARALLEL ...
3
votes
1answer
2k views

Should snapshot agent continue to run in transactional replication?

We have transactional replication running for a large number of publications on sql server 2008 R2 2 node active/active cluster. I have noticed that the snapshot agent job runs hourly and it looks ...
3
votes
1answer
169 views

Advice on setting up a Reporting server

I'd like to ask advice on setting up a reporting server please. We have a SQL Server (on a VM) that handles operations. (SQLOps) This primary SQL server instance has a secondary Log Shipping ...
3
votes
1answer
364 views

SQL Server Snapshot Replication and SRDF compatability

Is there anything that breaks down if you use snapshot replication and then use SRDF for disaster recovery (DR) on the snapshot publisher? Specifically I am asking is: On the DR system, would the DR ...
2
votes
2answers
2k views

SQL Server: in what situation can snapshot restore be blocked after SET SINGLE_USER?

In my tests, i have the following script: USE master; ALTER DATABASE [TestDB] SET SINGLE_USER WITH ROLLBACK IMMEDIATE RESTORE DATABASE [TestDB] FROM DATABASE_SNAPSHOT = 'TestDBSnapshot' In some ...
2
votes
2answers
215 views

Where do Database Snapshots store the information what pages have been copied to the snapshot files?

Database snapshot files are sparse files. Only when a page is modified the sparse file is being written to. Reads of the snapshot must be able to know whether the sparse file contains a copied page or ...
2
votes
1answer
383 views

Would using timestamps solve consistency issues with snapshot isolation?

I'm considering using Snapshot Isolation for some large queries being send from an Access 2007 frontend. These queries are occasionally causing ASYNC_NETWORK_IO waits, and some blocking as well. I'm ...
2
votes
2answers
2k views

SQL Server Transactional replication failed due to snapshot agent failure

I'm trying to set transactional replication between 2 SQL Server 2012 named instances. I've followed a step by step manual and created a Publication. But once I look into Replication Monitor I Get ...
2
votes
1answer
102 views

Online index maintenance in SQL Server using SNAPSHOT isolation level

I have recently altered our SQL Server 2008 R2 database to enable SNAPSHOT isolation level and made appropriate changes to hibernate to run all transactions in SNAPSHOT mode. I have however noticed ...
2
votes
1answer
6k views

How to Create Snapshot Backups in MySQL

I've seen a lot of people talking about snapshots backup, even I'm reading a book about mysql but nobody explain the code how to make a snapshots backup. This is what the book says: flush tables ...
2
votes
1answer
424 views

Sql Server 2008r2 Replication Snapshot Agent Hang

I am setting up a new merge publication, but I can not get the snapshot agent to run successfully. In fact, I can not run any snapshot agents for any of the other publications on this server now. ...
2
votes
1answer
336 views

SQL Server : database recovery from snapshot files

We have completely lost our SQL Server 2000 database in an accident. The only thing left is a snapshot folder which contains bunch of .sch, .idx and .bcp files. The sch and idx files have a clear ...
2
votes
1answer
97 views

How to make snapshot for new tables only

If there is a replication running for a large set of data, and I want to add one or more new tables, I normally add the articles to the replication and start the snapshot agent. Since there's a lot ...
2
votes
3answers
204 views

Snapshot replication - How to detect when a snapshot has arrived on the Subscriber from the Subscriber DB

I have snapshot replication set up on a server which publishes to a second server as part of a scheduled SQL Server Agent job. When the snapshot finishes, I would like to detect when each table has ...
2
votes
0answers
83 views

DB snapshot goes into SUSPECT mode (SQL 2014 on WIN2K8R2)

I was hoping someone here might have encountered this sort of issue and if so what did you do to fix it. Here's some details: DB server: SQL 2014 Enterprise (12.0.4100.1) OS: Windows 2008R2 ...
2
votes
0answers
25 views

Transactional Replication breaks when schema is changed in Publisher

We have set up Transactional replication where in two Publishers feed into one Subscriber , now if try to change the schema of any one Publishers or both publishers, replication breaks. We have ...
2
votes
1answer
177 views

SQL Server 2012 - Dropping Snapshots takes hours

We recently did a SQL Server upgrade from 2005 to 2012. We have a nightly job that drops a snapshot of an active database. The snapshots gets created again later in the day. Before upgrading, in SQL ...
2
votes
0answers
35 views

Snapshot Agent - Transactional Replication - Why a complete snapshot?

Often, I will add a single article to an existing transactional replication publication. I then start the snapshot agent to copy the new article and it's data over to the subscriber. Most of the time, ...
2
votes
0answers
387 views

Why does a simple select query produce a deadlock? [closed]

I am trying to analyze randomly occurring deadlock problems on an SQL Server 2008 R2 database. The deadlocks occur in very rare cases when SSRS tries to access one of 5 different stored procedures. ...
2
votes
2answers
1k views

Snapshot not picking up new articles in SQL Server 2012 transaction replication when added through script

I am trying to add new articles to an existing publication in SQL Server 2012. I am adding the article to the publication with the syntax --add the table into the correct publication sp_addarticle ...
2
votes
3answers
2k views

Transactional Replication snapshot locking Publisher db from beginning

I have recently upgraded my remote distributor to 2008r2. I am getting complete system locks when attempting to generate a new snapshot in the day when we have added an article to the publication (we ...
1
vote
3answers
46 views

how can database snapshot to be used to recover data?

I know the logic behind database snapshot and how it works. But my problem is how can database snapshot to be used to recover data? can we take a backup of database snapshot and restore it in a new ...
1
vote
2answers
969 views

Is it safe to copy DB files directly from an LVM snapshot?

I saw two different approaches for backing up database with LVM snapshot. This article suggests spawning another MySQL instance to do an SQL dump. MYSQL Performance Blog suggests that it is safe to ...
1
vote
2answers
3k views

Can I time out my scripted “FLUSH TABLES WITH READ LOCK;”?

I have a single Enterprise Linux 6 system running MySQL 5.5. I am attempting to use LVM to capture a weekly filesystem snapshot. However, as many of us have experienced, "FLUSH TABLES WITH READ ...
1
vote
1answer
57 views

Can you provide rights to a snapshot without providing rights to the database?

Is it possible to give a user or group rights to a snapshot without giving them rights to the database if the database and snapshot both reside on the same instance?