Questions tagged [in-memory-database]
An in-memory database (IMDB; also main memory database system or MMDB) is a database management system that primarily relies on main memory for computer data storage. It is contrasted with database management systems which employ a disk storage mechanism.
in-memory-database
886
questions
99
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View content of H2 or HSQLDB in-memory database
Is there a way to browse the content of an H2 or an HSQLDB in-memory database for viewing? For example, during a debugging session with Hibernate in order to check when the flush is executed; or to ...
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votes
17
answers
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redis-server in ubuntu14.04: Bind address already in use
I started redis server on ubuntu by typing this on terminal: $redis-server
This results in following > http://paste.ubuntu.com/12688632/
aruns ~ $ redis-server
27851:C 05 Oct 15:16:17.955 # Warning: ...
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72
votes
2
answers
16k
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How to suppress InMemoryEventId.TransactionIgnoredWarning when unit testing with in-memory database with transactions?
I'm using an EF Core in-memory database and I'm trying to run a unit test on a method that uses transactions:
using (var transaction = await _context.Database.BeginTransactionAsync())
{
_context....
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votes
2
answers
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Why Spark SQL considers the support of indexes unimportant?
Quoting the Spark DataFrames, Datasets and SQL manual:
A handful of Hive optimizations are not yet included in Spark. Some of
these (such as indexes) are less important due to Spark SQL’s
in-...
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51
votes
5
answers
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In django, how do I call the subcommand 'syncdb' from the initialization script?
I'm new to python and django, and when following the Django Book I learned about the command 'python manage.py syncdb' which generated database tables for me. In development environment I use sqlite ...
- 4,610
48
votes
3
answers
16k
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Multiple collections in Angular-in-memory-web-api
How do we create multiple collections using Angular-in-memory-web-api?
Not an issue with single collection. But I'm not able to implement it for multiple collections.
For example, I want to create ...
- 481
47
votes
2
answers
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How to isolate EF InMemory database per XUnit test
I am trying use InMemory EF7 database for my xunit repository test.
But my problem is that when i try to Dispose the created context the in memory db persist. It means that one test involve other.
...
- 1,145
40
votes
5
answers
4k
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Safe modelling of relational data in Haskell
I find it very common to want to model relational data in my functional programs. For example, when developing a web-site I may want to have the following data structure to store info about my users:
...
- 13.7k
38
votes
6
answers
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in-memory database in Python
I'm doing some queries in Python on a large database to get some stats out of the database. I want these stats to be in-memory so other programs can use them without going to a database.
I was ...
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35
votes
1
answer
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Why Apache Kafka Streams uses RocksDB and if how is it possible to change it?
During investigation within new features in Apache Kafka 0.9 and 0.10,
we had used KStreams and KTables. There is an interesting fact that Kafka uses RocksDB internally.
See Introducing Kafka Streams:...
34
votes
4
answers
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Create an in-memory database structure from an Oracle instance
I have an application where many "unit" tests use a real connection to an Oracle database during their execution.
As you can imagine, these tests take too much time to be executed, as they need to ...
- 80.6k
32
votes
2
answers
13k
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Create SQLite database in memory
Trying to learn a bit about PDO and is going through this tutorial. It has the following snippet of code:
<?php
try
{
$db = new PDO('sqlite::memory');
echo "SQLite created in ...
- 155k
28
votes
3
answers
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System.InvalidOperationException: Relational-specific methods can only be used when the context is using a relational database provider
System.InvalidOperationException:
Relational-specific methods can only be used when the context is using a relational database provider.
Getting the above mentioned error while using InMemoryDatabase ...
- 309
28
votes
1
answer
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Does Mongo DB have an In-Memory mode? [duplicate]
Possible Duplicate:
Embedded MongoDB when running integration tests
I want to use In-Memory mode for unit test, is there an in In-Memory mode like RavenDB?
- 1,223
28
votes
2
answers
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In C#, is there any way to have an in-memory file linked as an in-memory SQLite database with System.Data.SQLite?
What I want to do is something along the lines of the following:
using System.Data.SQLite;
using System.IO;
//My SQLite connection
SQLiteConnection myCon;
public void ReadAndOpenDB(string filename)
...
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27
votes
11
answers
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Why would someone need an in-memory database?
I read that a few databases can be used in-memory but can't think of reason why someone would want to use this feature. I always use a database to persist data and memory caches for fast access.
- 273
27
votes
9
answers
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When should I consider using a in memory database and what are the issue to look out for?
I was just think that now it is common to have enough RAM on your database server to cache your complete database why are the specialist in memory database (e.g TimesTen, see also Wikipedia page) ...
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26
votes
5
answers
32k
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Difference between In-Memory cache and In-Memory Database
I was wondering if I could get an explanation between the differences between In-Memory cache(redis, memcached), In-Memory data grids (gemfire) and In-Memory database (VoltDB). I'm having a hard time ...
- 489
20
votes
3
answers
7k
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In-Memory DB for Entity Framework 4
Does anyone know of a good in-memory DB that works well with .NET 4/EF 4? Specifically, I'm thinking of unit testing, such that each setup can easily create the DB, and populate it with default values,...
- 16.9k
19
votes
3
answers
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Why big companies use Mnesia instead of using Riak or CouchDB [closed]
I can see 2 big companies like Klarna and Whatsapp are using Mnesia as their in memory database (not sure how they persist data with Mnesia with 2GB limit). My question is: why companies like those, ...
- 5,689
19
votes
3
answers
9k
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Raw sql with EF Core and in-memory db provider
One of my API routes uses a raw sql merge into command in order to do an atomic upsert operation, and in my automated tests I've got a TestServer instance that uses the in-memory db provider. It gives ...
- 3,992
18
votes
1
answer
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EntityFrameworkCore SQLite in-memory db tables are not created
For integration tests I am using an EntityFrameworkCore SQLite in-memory db and creating its schema as per Microsoft docs, but when I attempt to seed data an exception is thrown that tables do not ...
- 8,495
16
votes
3
answers
16k
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How to shutdown Derby in-memory database Properly
I'm using derby as an embedded database. Furthermore, I'm using it's in-memory database option for my unit tests.
What I can't figure out is how to properly shut down (A quick look at the code) the ...
- 25.3k
16
votes
3
answers
12k
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Simple and reliable in memory database for fast java integration tests with support for JPA
My integration tests would run much faster if I used in-memory-database instead of PostgreSQL. I use JPA (Hibernate) and I need an in-memory-database that would be easy to switch to using JPA, easy to ...
- 19.4k
16
votes
7
answers
515
views
Out of Process in memory database table that supports queries for high speed caching
I have a SQL table that is accessed continually but changes very rarely.
The Table is partitioned by UserID and each user has many records in the table.
I want to save database resources and move ...
- 6,574
15
votes
4
answers
7k
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ASP.NET Core Testing - get NullReferenceException when initializing InMemory SQLite dbcontext in fixture
I have a test fixture in which I initialize my SQLite in-memory dbcontext, shown below:
public static MYAPPDBContext Create()
{
var options = new DbContextOptionsBuilder<MYAPPDBContext>()
...
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14
votes
2
answers
5k
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EF 7 - new ExecuteDelete and ExecuteUpdate methods not working on an in-memory database
I'm using the new EF 7 ExecuteDelete and ExecuteUpdate features and they are great. But when I try to write unit test for the functions that use them, these tests crash.
I'm using EF 7.0.1 on .NET ...
- 408
14
votes
1
answer
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Why is Redis SET performance better than GET?
According to the Redis benchmarks , Redis can perform 100'000 SET operations/s, and 80'000 GET operations/s. Redis being an in-memory DB, this seems surprising because typically one would expect that ...
- 10.1k
14
votes
2
answers
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Creating an in-memory table in PostgreSQL?
My understanding of an in-memory table is a table that will be created in memory and would resort to disk as little as possible, if at all. I am assuming that I have enough RAM to fit the table there, ...
- 1,531
14
votes
1
answer
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How is Partitioning done in Hazelcast
I am using Hazelcast v2.5. I have a few doubts related to partitioning in a cluster.
How are the partitions identified ?
When a m.get request is made how does Hazelcast identify in which partition ...
- 1,741
13
votes
5
answers
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Connect to a database in cloud
I have an SQLite database (110kb) in an S3 bucket. I want to connect to that database every time I run my Python application.
An option is to download database everytime I run the Python application ...
- 2,081
12
votes
6
answers
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What is namespace in aerospike
I'm new to Aerospike.
What is a namespace and how to create a namespace in aerospike?
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2
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Load CSV file located in the classpath for H2 Database
For tests purposes, I want to create and fill some tables using SQL scripts as well as CSV files.
So I created a SQL script like this one:
CREATE TABLE T_FOO (
...
) as select * from CSVREAD('...
- 80.6k
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votes
1
answer
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Does SQL Server support in-memory database?
I have basically a testing scenario, where I
Create database
Fill it with some data
Execute the business logic to be tested, which modifies the data. I don't own the business logic implementation or ...
- 26.2k
11
votes
3
answers
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How do I create a sqllite3 in-memory database?
One of the appropriate uses for sqlite3 is "in-memory databases". This sounds like a really useful tool for my C++ applications. Does anyone have an example of how this is done in C or C++? I'm ...
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votes
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Alternative to the TimesTen in memory database [closed]
I just found "Has anyone published a
detailed comparison between different
in-memory RDBMSs?" that is related
to my question.
TimesTen (see also) is a In-Memory Database from oracle.
It has a ...
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11
votes
1
answer
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sqlite:How to use in memory
I am trying to store my data in memory
here is what i have right now
//sq lite driver
Class.forName("org.sqlite.JDBC");
//database path, if it's new data base it will be created in project ...
- 11k
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5
answers
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Has anyone published a detailed comparison between different in-memory RDBMSs? [closed]
There are quite a few independent and not-so-independent studies comparing traditional RDBMSs but I haven't managed to find any good material on in-memory databases. I am primarily interested in ones ...
- 2,486
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votes
1
answer
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H2 Database - Unknown data type of MySQL script
I'm new in using in-memmory database.
I tried to use H2 database for developing project with spring boot, spring data JPA, but i got a problem when initialize application.
Caused by: org.h2.jdbc....
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"ids for this class must be manually assigned before calling save()" with string id
I got exception when I'm writing hibernate in memory test.
org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save():
@Entity
public ...
- 2,894
10
votes
1
answer
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Caching Systems - Redis vs Geode/GemFire
We are considering to use a caching system to our application to do data lookup. This data will change very infrequently. My findings came out with Redis, GemFire/Geode, VoltDB, Aerospike, Hazlecast ...
- 12.3k
10
votes
1
answer
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Efficiently store large list structure in RocksDB so that the data can be retrieved in pages
Description:
RocksDB is a key-value storage so we can simply serialise the list of objects & store the value corresponding to a key. This would be ok if the data in the list is small enough.
But ...
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votes
2
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780
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has anyone produced an in-memory GIT repository?
I would like to be able to take advantage of the benefits of GIT (and its workflows), but without the cost of disk access - I just would like to leverage the distributed revision control capabilities ...
- 3,056
10
votes
1
answer
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Is there a (open-source) MDX-based in-memory OLAP server? [closed]
I was wondering if there is a in-memory OLAP server which can handle MDX.
I found the Wikipedia article.
But it says nothing about in-memory functionality...
The only one I know of them is Mondrian, ...
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difference between in-memory and embedded databases
I want to know if my understanding is correct :
embedded : databases which are up if my application is up and are down if my application is down.
I am not referring the databases used in embedded ...
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3
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How to browse an in-memory SQLite database with the command line tool sqlite3
Is there a way to load an entire SQLite database into memory for faster results, using the sqlite3 CLI tool? Thanks!
- 3,097
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votes
2
answers
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In-memory Java DB [closed]
Are there any DBs for Java that can be run in an embedded mode with some tables being stored in-memory while loading others from disk? H2 and JavaDB seem to be the two leaders for Java DBs and I know ...
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8
votes
2
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in memory database h2 how long keep connection open?
I am testing currently a H2 DB in memory mode.
I set up a connection by
h2Con = DriverManager.getConnection(
"jdbc:h2:mem:db1", "SA", "");
I want to some imports with dbunit and set ...
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8
votes
1
answer
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views
Can I use in-memory Entity Framework 6.2.0 or if there any approach to do it [closed]
I want to use in-Memory entity framework , could you help me guys
I can't find a way to use In memory db @ entity framework 6.2.0
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votes
2
answers
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How to get the files uploaded in InMemoryUploadedFile django
I am developing an application in django 2.1 in which I must upload an undetermined number of audios through a modal and then pass the information to the view from which the modal is launched.
However,...
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