monetdb

Using tbl and src_monetdblite to access data

由 不打扰是莪最后的温柔 提交于 2019-12-11 15:56:51
问题 Sorry if this question has been asked elsewhere, I can't find it. I'm working through some basic examples in MonetDBLite. > dbGetQuery(dbcon, "SELECT MAX(mpg) FROM mtcars WHERE cyl = 8") L3 1 19.2 works, but > ms <- MonetDBLite::src_monetdblite("./DB") > t <- tbl(ms, "mtcars") Error in UseMethod("tbl") : no applicable method for 'tbl' applied to an object of class "c('src_monetdb', 'src_sql', 'src')" It seems that it's trying to assign the db to t not the table. Any suggestions would be

dplyr & monetdb - appropriate syntax for querying schema.table?

由 倾然丶 夕夏残阳落幕 提交于 2019-12-11 11:56:31
问题 In monetdb I have set up a schema main and my tables are created into this schema. For example, the department table is main.department . With dplyr I try to query the table: mdb <- src_monetdb(dbname="model", user="monetdb", password="monetdb") tbl(mdb, "department") But I get Error in .local(conn, statement, ...) : Unable to execute statement 'PREPARE SELECT * FROM "department"'. Server says 'SELECT: no such table 'department'' [#42S02]. I tried to use "main.department" and other similar

CSV load error with monetdb & R

由 为君一笑 提交于 2019-12-11 11:08:59
问题 I'm trying to load various CSVs into monetdb, using R and RStudio but I get the error below. This is the code (code tested with the iris dataset & generally working fine) and the error message: > monetdb.read.csv(conn,fnamed,nrows=nrows,header=TRUE,tablename=tabled,delim=",") /Users/Enzo/NHS/data/sha_lookup.csv /Users/Enzo/NHS/data/sha_lookup.csv Error in .local(conn, statement, ...) : Unable to execute statement 'copy 12 offset 2 records into sha_lookup from '/Users/Enzo/NHS/data/sh...'.

MonetDB refresh data in background best strategy with active connections making queries

由 感情迁移 提交于 2019-12-11 10:28:58
问题 I'm testing MonetDB and getting an amazing performance while querying millions of rows on my laptop. I expect to work with billions in production and I need to update the data as often as possible, let say each 1 minute or 5 minutes worst case. Just updating existing records or adding new ones, deletion can be scheduled once a day. I've seen a good performance for the updates on my tests, but i'm a bit worried about same operations over three of four times more data. About BULK insert, got 1

How to use connection pooling for Monetdb?

由 六月ゝ 毕业季﹏ 提交于 2019-12-11 02:33:54
问题 Can some tell me how to use connection pooling with MonetDb? Do I just append these args to the URL "poolminimum=1;poolmaximum=5;"? 回答1: No, by itself, the driver does not pool connections. You could use c3p0 (http://www.mchange.com/projects/c3p0/) to create a connection pool for MonetDB JDBC connections. However, please be aware that MonetDB uses optimistic concurrency control and table-level locking, so firing updates at a single table from multiple connections will have an increasing risk

How to have the list of table in a monetdb database?

由 大城市里の小女人 提交于 2019-12-06 04:39:02
问题 In postgresql, one can have all tables names by running the following query SELECT table_name FROM information_schema.tables WHERE table_schema='public'; Is there something similar in monetdb to have the list of tables ? 回答1: I finally find this query select tables.name from tables where tables.system=false ; 回答2: If you are using mclient, in the command line you could simply use the command "\d" to list all the tables in the current database. sql> \d TABLE sys.table1 TABLE sys.table2 TABLE

How to have the list of table in a monetdb database?

由 僤鯓⒐⒋嵵緔 提交于 2019-12-04 07:04:55
In postgresql, one can have all tables names by running the following query SELECT table_name FROM information_schema.tables WHERE table_schema='public'; Is there something similar in monetdb to have the list of tables ? I finally find this query select tables.name from tables where tables.system=false ; Vijay Krishna If you are using mclient, in the command line you could simply use the command "\d" to list all the tables in the current database. sql> \d TABLE sys.table1 TABLE sys.table2 TABLE sys.table3 Additionally, use the command "\d tablename" to view the metadata of a table - equivalent

MonetDB test client application not linking

由 痞子三分冷 提交于 2019-12-02 19:49:16
问题 I tried to compile test application for MonetDB under Ubuntu 14.04 LTS Trusty Tahr. I followed the download instructions from official site, installation was successful, then I installed a bunch of other packages in order to copmpile it. Now when I try to compile and link test application I get the following errors: libtool: compile: gcc -c -I/usr/include/monetdb test.c -fPIC -DPIC -o .libs/test.o libtool: compile: gcc -c -I/usr/include/monetdb test.c -o test.o >/dev/null 2>&1 libtool: link:

MonetDB test client application not linking

由 心已入冬 提交于 2019-12-02 10:01:30
I tried to compile test application for MonetDB under Ubuntu 14.04 LTS Trusty Tahr. I followed the download instructions from official site , installation was successful, then I installed a bunch of other packages in order to copmpile it. Now when I try to compile and link test application I get the following errors: libtool: compile: gcc -c -I/usr/include/monetdb test.c -fPIC -DPIC -o .libs/test.o libtool: compile: gcc -c -I/usr/include/monetdb test.c -o test.o >/dev/null 2>&1 libtool: link: gcc -o test test.o -lmapi -lstream -lssl -lcrypto -lcurl -lz test.o: In function `die': test.c:(.text
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