MonetDB is an open-source implementation of a column-oriented database. It is focused on analytical applications on a main memory resident database. MonetDB is a relational database and provides an SQL top-level interface. It is actively developed at CWI in Amsterdam, The Netherlands.
Questions tagged [monetdb]
441 questions
3
votes
1 answer
How to execute a MAL function in monetdb?
I'm reading the MonetDB Internal Description because I'm interested to implement a special procedure direct in the MonetDB Algebra Language (MAL) instead of SQL-frontend (I hope to gain more performance by doing so). Here is a sample MAL code…
Fopa Léon Constantin
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3
votes
1 answer
how do I install MonetDB on Centos 6.5?
I would like to install MonetDB on Centos 6.5.
MonetDB website describes how to install for Debian / Ubuntu / Fedora distributions.
I've a server on Centos 6.5 (and I'm not entirely sure to which Fedora distribution this should compare…
Enzo
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3
votes
0 answers
Importing huge csv into MonetDB
We are running MonetDB on an OpenIndiana fileserver (Xenon E5-1620 / 16GB RAM, RAM will be ugraded soon).
We merge many small csv files to two big ones.
The first is around 25GB but the second is around 125GB.
Importing the first one works fine but…
BayerSe
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3
votes
2 answers
Use a columnar database like MonetDB to avoid dimensional modeling?
I was wondering if you think it's reasonable, using monetdb (or another columnar database) to put all of your data in one big, flat table rather than breaking it up into several related tables.
For example, a database of used cars, flat, might look…
Michael Fox
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2
votes
1 answer
would monetdb work faster with boolean or varchar(1) data types?
Would a query run faster in a column defined as boolean or as varchar(1) in monetdb ?
queries would look like:
with varchar(1)
select * from many_many_rows where has_fancy_value = 'T'
with boolean
select * from many_many_rows where has_fancy_value…
Federico
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2
votes
1 answer
How would MonetDB perform with multiple sql copy operations running at the same time?
I need to import a large CSV file into MonetDB and I'm wondering if it would be possible to split the file in two and run two scripts like:
mclient -u monetdb -d mydb < import1.sql
mclient -u monetdb -d mydb < import2.sql
where
import1.sql issues…
Federico
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2
votes
1 answer
invalid credentials for user 'monetdb' when using the official docker image and a .monetdb file
How to recreate my problem
Creating the MonetDB Container
I have this setup (using windows with Docker Desktop).
Create the official monetdb docker container with the follwing command:
docker run -v $HOME/Desktop/monetdbtest:/monetdbtest -e…
Bishares
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2
votes
1 answer
Monetdbe Python UDF
Given that monetdbe is a Python package, I'm optimistic that Python user-defined-functions are possible, but I haven't been able to find an example. I've tried this:
drop function every_other_letter;
create function every_other_letter(s…
dcc310
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2
votes
1 answer
Looking for Special characters in MonetDB table columns
I am new to MonetDB, I would like to check if there are any special characters in any of the columns in MonetDB.
For example, I have a test Database and the table name is Lmr. I would be to check if any of the columns in table lmr contains special…
KSp
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2
votes
1 answer
monetdb regexp select
I'm doing some testing with MonetDB.
The gist of the query I'm trying perform (using borrowed syntax) goes like this:
SELECT mystring FROM mytable WHERE mystring REGEXP 'myxpression';
MonetDB does not support this syntax, but the docs claim that it…
airan
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- 2
2
votes
0 answers
Problems with user-defined aggregate functions
I'm having some trouble when defining aggregate functions. Here’s a reproducible example:
library(MonetDBLite)
library(dplyr)
library(DBI)
dbdir <- tempdir()
con <- dbConnect(MonetDBLite())
dbWriteTable(con, "mtcars", mtcars, overwrite = TRUE)
ms…
user6948837
2
votes
0 answers
MonetDBLite - problems installing package
I've been trying to run this script:
https://github.com/ajdamico/asdfree/blob/master/Pesquisa%20Nacional%20por%20Amostra%20de%20Domicilios/download%20all%20microdata.R
But on this line
install.packages( c( "MonetDBLite" , "survey" , "SAScii" ,…
Roberto Dumke
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2
votes
1 answer
Does MonetDB support parallel query execution when using merge tables?
I have partitioned my data set into two separate sets of 5M rows. Each partition is loaded into a table on a machine of its own. I use a central monetdb instance where I register both tables as remote tables and add them to a merge table.
When I run…
vdeurzen
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2
votes
2 answers
"ORDER BY" in subquery - not avaliable in MonetDB?
I found that, when using order-by directly, it is ok.
SELECT t0."D" AS fd,
SUM(t0."SD") AS top
FROM "mock_table_1" AS t0
GROUP BY t0."D"
ORDER BY top ASC
LIMIT 10
but when using it in a subquery, an syntax error is reported.
SELECT * FROM (
…
luochen1990
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2
votes
1 answer
MonetDBLite without R in a C++/Qt application
Is there a way to use MonetDBLite as a storage engine in a C++ application without installing the R package? Or are there any other ways of using MonetDB as an embedded database like SQLite?
olafpadme
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