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
0
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4 answers
Replace an entire field value in a file using awk or other
I have an export from postgresql table with multiple fields, including boolean (exported by postgresql as t and f character), and I need to import it in another database (monetdb) that won't understand t/f as bool values.
(EDIT removed spaces to…
ant1j
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1 answer
monetdb remote table: cannot register
I have two nodes and am attempting to create a remote table. To set up I do the following:
on each host:
$ monetdbd create /opt/mdbdata/dbfarm
$ monetdbd set listenaddr=0.0.0.0 /opt/mdbdata/dbfarm
$ monetdbd start /opt/mdbdata/dbfarm
On the first…
Kelly Burkhart
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1 answer
Load CSV with blank values in MonetDB
I am trying to load a CSV file where values that should be NULL are simply blank. For example, consider the following schema:
CREATE TABLE test (
float a,
float b,
float c
);
I am trying to load a file that looks like this (some rows…
agg212
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0 answers
Is it possible to create a function that creates smaller column than input column
I'm working on a Monetdb Database with embedded R. Now, I want to process the data from a column, which basically reduces the amount of values.
The question now is if it is possible to create a R function that takes an input column with n values and…
Frank
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- 5
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votes
1 answer
monetdb : there are no available connections for 'voc'
Me & my computer (mac) are trying to follow with the monetdb tutorial (https://www.monetdb.org/Documentation/UserGuide/Tutorial)
We went up until running this mclient -u monetdb -d voc, entered "monetdb" as a password and the following message was…
Pelican
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0 answers
MonetDb: Embedded R aggregate function with multiple output columns
I'm using MonetDB and embedded R with a huge amount of accelerometer sensor data. I created an aggregate function which calculates a Fast Fourier Transformation on the sensor data and extracts a single value.
CREATE AGGREGATE fft_max_s(val double)…
Frank
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- 5
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2 answers
monetdb select last n rows
My monetdb table has over 100k rows. I want to select the last n rows from the table. Will it be possible to query only the last n records without scanning the entire table?
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1 answer
Drop a local temporary table within a function in MonetDB
Consider the following scenario. I have a bunch of user defined functions, f_i, that create, populate, and use a local temporary table with the same name res:
create function f_i()
returns table( … )
begin
# Result stats table.
create…
영민 카이 앤절
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votes
1 answer
Dplyr backend is not able to find applicable method for 'sql_translate_env'
I try to run a simple dplyr command, on an monetdb SQL-backend. The connection itself seems to work, but the dplyr call fails. I restarted the RSession and tried to reinstall the MonetDB.R package again, without success.
library(dplyr)
db <-…
NaN
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1 answer
How to enable (force) compression in MonetDB?
I installed MonetDB and imported a (uncompressed) 291 GB TSV MySQL dump. It worked like a charm and the database is really fast, but the database needs more than 542 GB on the disk. It seems like MonetDB is also able to use compression, but I was…
NaN
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0
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0 answers
Monetdb unable to execute queries with a where clause against remote tables
I have been trying remote tables in monetdb. I have setup a remote table mapped to an existing table on a monetdb instance running on another host.
I am able to perform some basic queries, However I am unable to use the where clause: If I try to…
Manuel Pagliai
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votes
1 answer
monetdb, group by
Working in MonetDB, I have an 'entrytime' column that contains a time value. I have:
select "minute"(entrytime) as unitTime, period
from schema1.zones
where date1 >= eDate and date1 <= xDate and id=256
group by unitTime, period
But I…
flavour404
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0 answers
Selecting single row by ID in MonetDB
It seems MonetDB still performs full table scans even where one record has to be pulled by some ID column.
select a, b, c from mytable where id = 100;
Is there anything that can be done to improve performance here? It doesn't seem like creating an…
marcin_koss
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1 answer
Loading TPCH in MonetDB
i am having trouble importing the data of the TPCH-Benchmark into my monetDB-Database.
I am creating the first table like this:
CREATE TABLE "tpch"."customer" ( "c_custkey" INTEGER NOT NULL, "c_name" VARCHAR(25) NOT…
uv239
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- 10
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votes
1 answer
How to implement AUTO_INCREMENT properly in MonetDB?
I have two MonetDB tables using auto-increment to generate unique IDs for each row. Each row in the child table refers to one row in the parent table (modeling a 1:n relationship):
CREATE SEQUENCE "test"."seq_parent" as integer START WITH 1;
CREATE…
dasup
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