Database Administrators Stack Exchange
Database Administrators Stack Exchange

Questions tagged [distributed-databases]

79 questions
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Consistency in ACID and CAP theorem, are they the same?

From my understanding, the consistency in ACID is ensuring the data integrity. However, the consistency in CAP means the data can appear quickly in distributed system. Does that mean: they are not the same concept?
Yang Xia
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What is the reasoning behind the CAP theorem?

http://en.wikipedia.org/wiki/CAP_theorem http://www.cs.berkeley.edu/~brewer/cs262b-2004/PODC-keynote.pdf I think it is not very straightforward why only two of Consistency Availability Partition tolerance can hold for any given distributed…
Lazer
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What is the difference between Federated and Decentralized Data Warehouse?

I can not find any clear definitions or explanations of any of these. Both seem decentralized. It appears that in Federated DWH, the data is distributed and not integrated into a single repository and accessed from distributed sources. While in…
LifeH2O
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9
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1 answer

Why can't we perform joins in a distributed database like Bigtable?

From this answer to "What database does Google use?": Bigtable is not a relational database. It does not support joins nor does it support rich SQL-like queries. Is this obvious? I do not understand why.
Lazer
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9
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3 answers

Why is it more difficult to horizontally scale a relational database than a NoSQL database like MongoDB?

Is the main reason for the difficulty in horizontally scaling / distributing an RDBMS because of an adherence to ACID transactions? Is it the fact that multiple tables are so interconnected, or something else? My impression is that it’s mostly the…
Greg Thomas
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7
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Horizontally scaling SQL Server, distributing the database with sharding

I wanted to know if there is any way to distribute a SQL Server (I'm using 2012 version) database accross multiple nodes. I'm trying to compare READ queries performance between SQL Server and MongoDB. The distribution is all set with MongoDB with…
user98851
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6
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1 answer

Insert into linked server fails with "The transaction manager has disabled its support for remote/network transactions"

Two servers: sq009 and sq202, both running SQL Server 2012 SP3. sq202 is the SQL Server hosting the DB for our ERP system, Sage 500. sq009 is the SQL Server hosting the DB for our IBM Maximo instance. The situation: a trigger exists on a table in…
Brie
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5
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What are alternatives to Replication to distibute data (Microsoft SQL Server)

Is anyone knowledgeable of alternatives to SQL Server replication? I have a scenario where separate databases will share a lot of the same data which complex queries will match against. We want to separate the databases out from each other (i.e.…
user2321
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4
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Simultaneous money withdrawls from a distributed/replicated database

Lets say I have $10 in my bank account. The database is replicated in North America and Asia. At the exact same time I do a withdrawl of $10 in N. America and in Asia, meaning that my withdraw would do work on two different copies of the data. How…
DbQuestioner88
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Does the pgpool-II extension allow for parallel execution of any query?

I read about pgpool-II here and it states that: Using the parallel query function, data can be divided among the multiple servers, so that a query can be executed on all the servers concurrently to reduce the overall execution time. Parallel query…
David
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Difference between partitioning and fragmentation

I'm trying to learn something about distributed databases and I stumbled upon the concepts of fragmentation and partitioning. It seems to me as if both do the same thing and produce similar results (deviding a relation…
nozzleman
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How do distributed databases follow unique constraints?

Lets say i have an application where user can register, and the username has to be unqiue value. Now lets say i have N partitions and for each partition i have M replicas with multiple leaders. Now i have questions regarding these…
Johnyb
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DB2 Express-C 10.1 database move to DB2 Work group Server/Enterprise Edition

I have not done such migration before and I want to know if I am going to face such issues when moving my database (tables,views,table-spaces,functions,procedures,etc.) to other DB2 distribution. If there will be some problems, will it be better to…
gotqn
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Upgrading Remote Distributor in SQL Server Replication

I'm upgrading my remote distributor from 2005 to 2008r2, it is performing transactional replication only. this is a prerequisite to completing an upgrade of the Publisher to 2008r2. Script replication environment. STOP REPLICATION FROM…
DamagedGoods
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Git as distributed and decentralized storrage with regard to ACID and CAP

When using Git to store documents distributed and decentralized it can be considered as a database. How would the ACID properties and the CAP theorem correspond to git in this case? I think one has to distinguish between a single repository and the…
white_gecko
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