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
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1 answer
R Data Types to MonetDB Data Types
I am trying to insert a data frame into MonetDB using DBI::dbWriteTable() with the MonetDBLite driver and am having to adjust column types in both the MonetDB table and the R data frame.
I am wondering if there is a mapping of data types from R to…
bdetweiler
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0 answers
Case insensitive/Case preserving Monetdb tables
Can I set monetdb to be case insensitive (but case preserving) ?
I am aware that workarounds exist: For example using ilike for search, and using lower in group by clauses but, especially in the latter case, the performance degradation is…
Manuel Pagliai
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1 answer
Read Table, block and tuple
I have inserted into the orders table from TPCH using MonetDB.
Now I'd like to read it programmatically.
How can I read a table, block and tuple on monetDB?
Is there any way to read an specific block from a table?
Namom Alencar
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2 answers
How to debug a SQL/Python UDF in MonetDB
Using native Python code in SQL UDFs in Monetdb is really powerful. BUT, debugging such UDFs could benefit from more support. In particular, if I use the old-fashioned print('debugging info') it disappears in the big black void.
create function…
mkersten
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3 answers
SQL concatenate many tsv files into single table in a database, while keeping track of file source (MonetDBLite)
I am using the MonetDBLite R package to create a MonetDB. I can create database tables just fine using the instructions from here, with the following code:
library(DBI)
library(MonetDBLite)
# Write tsv file of mtcars
write.table(mtcars,…
lmrta
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1 answer
Can't access existing MonetDB with dplyr
I created a MonetDBLite database yesterday, populated it, and was accessing it with dplyr, however this morning I don't seem able to use dplyr.
Here's my connection:
statcast_db <-…
BillPetti
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(MonetDB) available main-memory
I'm testing MonetDB in CentOS for a BI database, and during inserts, reaching 8 million records, my database has crashed with the message "database 'olap1' (9111) has crashed (dumped core)" (from log).
In the log I saw that monetdb is only using 4gb…
Fasolo
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1 answer
importing tbl file to monetDB on windows 10
I am having trouble importing the data of the TPCH-Benchmark (generated with dbgen) into my monetDB-Database.
I've already created all the tables and I'm trying to import using the following command:
COPY RECORDS INTO region FROM "PATH\region.tbl"…
Ruben Alves
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1 answer
Does MonetDB support thousands of sparse columns efficiently?
Does MonetDB support thousands of sparse columns efficiently? E.g.: empty fields don't incur overhead, not a lot per-column overhead, etc.
Geert-Jan
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MonetDB: Enumerate groups of rows based on a given "boundary" condition
Consider the following table:
id gap groupID
0 0 1
2 3 1
3 7 2
4 1 2
5 5 2
6 7 3
7 3 3
8 8 4
9 2 4
Where groupID is the desired, computed column, such as its value is incremented whenever the gap…
영민 카이 앤절
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Monetdb query cancelling
I am using Monetdb in a java application via the JDBC driver.
I need to cancel long running queries, or queries that are no longer relevant.
Since monetdb JDBC driver does not support jdbc statement cancelling, I have implemented my query cancelling…
Manuel Pagliai
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0 answers
MonetDB database shut down error
After cleaning up some tables in MonetDB, trying to connect to mclient and getting kicked out.
monetdbd: internal error while starting mserver, please refer to the logs
merovingian.log ->
2017-02-16 16:40:54 MSG ame[1672]: # MonetDB 5 server…
marcin_koss
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not in clause, is there a better way
I am trying to exclude id numbers that have been seen before, my query is
select id from table1 where date1 >= eDate1 and date1 <= eDate2 and zId = 256
and id no in
(select id from table1 where date1 < eDate1 and zId = 256)
MonetDB.
Is there a…
flavour404
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I cannot establish a connection to MonetDB using pymonetDB in Python
I'm trying to use MonetDB in Python to perform some tasks on a huge dataframe. I've installed the suggested API and it has successfully loaded. But when I try to establish the connection, I always get the same error:
[Errno 10061] No connection…
Evangelista
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3 answers
SELECTing the column names for another SELECT - possible?
I have a table t1 with a 'foo' column, and records containing 'bar' and 'baz' in column 'foo'. I also have a table t2 with columns 'bar', 'baz' and 'quux'. I want to do something like the following:
SELECT (SELECT foo from t1) FROM t2;
that is, get…
einpoklum
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