Hi,
I am getting some strange exceptions using MonetDB JDBC 1.8/1.9, and I
decided to look into the code. While inspecting the code I came across
these strange lines in MonetConnection.executeQuery(String[] templ,
String query) method
(http://dev.monetdb.org/hg/MonetDB/file/718da8ca0a1a/java/src/nl/cwi/monetdb…).
In my case, these lines are executed for sure when doing a batch
insert. So, suppose that the batch contains the following commands (as
constructed by the MonetStatement.executeBatch() method):
exec 1(1, 957339737330229055);
exec 1(2, 278262503670654331);
exec 1(805306369, 3763943296910752235)
The lines in question take the above commands as a string, prepend a
's' character and append a ';' at the end. The resulting commands,
which are written in the server's socket, are the following:
sexec 1(1, 957339737330229055);
exec 1(2, 278262503670654331);
exec 1(805306369, 3763943296910752235);
First of all, I am not familiar with the internals of JDBC drivers.
Taking this into account, is this what it should be? From a symmetric
point of view, I would assume that the correct would be the following:
sexec 1(1, 957339737330229055);
sexec 1(2, 278262503670654331);
sexec 1(805306369, 3763943296910752235);
That is, it should prepend a 's' character before an exec command.
Last, are these exec commands (with or without a prepending 's')
specific to MonetDB? In either case, is there any documentation to get
familiar with their meaning?
Thanks a lot,
Babis
hi,
I tried to compile the latest monetdb(11.5.3) on centos6 x64, but the pcre library is not found when configure. I'm sure that the pcre library has been installed via compiling the source, the libpcre.la, libpcre.a, libpcre.so has been installed in /usr/local/lib. I also configure monetdb like:
pcre_LIBS=/usr/local/lib pcre_CFLAGS=/usr/local/include ./configure, but it doesn't work. How to fix this problem?
Any reply will be apprecitated.
Hello,
I'm attempting to use monetdb for some temporal queries. Some queries
require the output to be coalesced. For example, with schema emp(empno int,
ts date, te date) the tuples (00001, '1/1/2001', '2/1/2001'), (00001,
'2/1/2001', '3/1/2001') are output as (00001, '1/1/2001', '3/1/2001').
My coalescing query works in both MS SQL Server and DB2 but MonetDB gives me
the error "SELECT: no such column 'm.ts'". 1) A leaner alternative query
form using window clauses (ROWS UNBOUNDED PRECEDING) doesn't appear to be
supported in MonetDB. So I'm stuck. Any help would be appreciated.
Query:
WITH Emps(empno, ts, te) AS
(SELECT empno, ts, te FROM emp)
SELECT DISTINCT F.empno, F.ts, L.te
FROM Emps AS F, Emps AS L
WHERE F.ts < L.te
AND F.empno = L.empno
AND NOT EXISTS
(SELECT * FROM Emps AS M
WHERE M.empno = F.empno
AND F.ts < M.ts AND M.ts < L.te
AND NOT EXISTS
(SELECT * FROM Emps AS T1
WHERE T1.empno = F.empno
AND T1.ts < M.ts AND M.ts <= T1.te)
)
AND NOT EXISTS
(SELECT * FROM Emps AS T2
WHERE T2.empno = F.empno
AND ((T2.ts < F.ts AND F.ts <= T2.te)
OR (T2.ts <= L.te AND L.te < T2.te))
);
Thanks,
Alex
--
View this message in context: http://old.nabble.com/Temporal-coalescing-query-error-tp32742108p32742108.h…
Sent from the monetdb-users mailing list archive at Nabble.com.
I'm using Monet 11.5 on Ubuntu 11.04.
Ive created a database and am attempting to run a series of queries
against it with a test script. This is in attempt to use Monet with
Apache Jena. I had earlier mailed about a problem with temp tables, but
have dodged that by using the monetdb account for now.
The first few succeed, but then I get the following error:
java.sql.SQLException: Read from localhost:50000: End of stream
reached (mserver still alive?)
Why does this happen, under what circumstances does it arise ? Is there
anything I can do to avoid it ?
This is the query that it fails on:
SELECT R_1.lex AS V_1_lex, R_1.datatype AS V_1_datatype, R_1.lang AS
V_1_lang, R_1.type AS V_1_type,
R_2.lex AS V_2_lex, R_2.datatype AS V_2_datatype, R_2.lang AS
V_2_lang, R_2.type AS V_2_type
FROM
( SELECT T_1.s AS X_1
FROM Triples AS T_1
WHERE ( T_1.p = 2004134117598721274
AND T_1.o = 435905340492217258 )
) AS T_1
LEFT OUTER JOIN
Triples AS T_2
ON ( T_2.p = 3816485599920428794
AND T_1.X_1 = T_2.s )
LEFT OUTER JOIN
Nodes AS R_1
ON ( T_1.X_1 = R_1.hash )
LEFT OUTER JOIN
Nodes AS R_2
ON ( T_2.o = R_2.hash )
Hi everyone:
How can I test if a VARCHAR field has numeric data?, at SQLServer I use
IsNumeric() clause, what can i use in MonetDB?
thanks in advance
Osmin
The MonetDB team at CWI/MonetDB BV is pleased to announce the
Aug2011-SP2 bugfix release of the MonetDB suite of programs.
More information about MonetDB can be found on our website at
http://www.monetdb.org/.
For details on this release, please see the release notes at
<http://www.monetdb.org/Downloads/ReleaseNotes>.
As usual, the download location is <http://dev.monetdb.org/downloads/>.
Aug 2011-SP2 bugfix release
Client Package * ODBC: Implemented a workaround in SQLTables for bug
2908.
* Small improvement to mclient's table rendering for
tables without any rows. Previously, the column names
in the header could be squeezed to very small widths,
degrading readability.
* Python DB API connect() function now supports PEP
249-style arguments user and host, bug #2901
* mclient now checks the result of encoding conversions
using the iconv library.
* Fixed a source of crashes in mclient when a query on
the command line using the -s option is combined with
input on standard input (e.g. in the construct mclient
-s 'COPY INTO t FROM STDIN ...' < file.csv).
* Fixed bug 2897 where slow (network) reads could cause
blocks to not be fully read in one go, causing errors
in the subsequent use of those blocks. With thanks to
Rémy Chibois.
* Fixed a bug in mclient where processing queries from
files could result in ghost empty results to be
reported in the output
Merovingian * Resolved problem where monetdbd would terminate
abnormally when databases named 'control', 'discovery'
or 'merovingian' were stopped.
* monetdbd get status now also reports the version of the
running monetdbd
* Improved response time of 'monetdb start' when the
database fails to start.
* Fixed a bug in monetdbd where starting a failing
database could incorrectly be reported as a 'running
but dead' database.
* To avoid confusion, all occurrences of merovingian were
changed into monetdbd for error messages sent to a
client.
Bug Fixes * 2346: mkey.bulk_rotate_xor_hash MAL exception
* 2712: un-rolled-back savepoints cause crash upon
scenario exit
* 2774: COPY INTO of double (~1.0e-310) cannot be
imported.
* 2890: Slow execution of COUNT in combination with
DISTINCT
* 2894: No consistent behavior of implicit cast of
integer to double
* 2897: Mapi.pm: short reads not handled when reading
blocks from server
* 2898: order by for multiple (two) columns fails for
large tables when second ordering is 'desc':
"mat.refine_reverse' undefined"
* 2900: rand(int) should not return NULL
* 2901: Make keyword arguments in Python DB API connect()
function more standard
* 2904: TypeException after calling UDF in other than sys
schema (when it is initialised)
* 2906: "ALTER TABLE mytable SET READ ONLY" results in
server segfault
* 2908: SQL query produces error with MAL statements
* 2909: query result is not displayed when history = true
Hi guys,
I just joined this amazing group, May I asking a stupid question about Monetdb if I haven't run out my 'ask stupid question' budget?
My question are as following:
* Regarding to the work cluster, Does Monetdb support smoothly expand while I have to add new server to the work cluster in necessary? How to add a new server to a work cluster?
* Does Monetdb supply any analytical functions? Do we have any documents or materials related to what kind of analytical functions can be used?
BTW: Any advices or suggestions regarding building data mart with Monetdb would be highly appreciated!
Thanks in advance,
Tony
Hello,
I am presently evaluating MonetDB's performance for a client using big data sets. We are very happy with the impressive results. Something that is harder to evaluate is how wide spread is MonetDB's usage. There are some references on the home page, but as it says in the introductory passage, most usage applications are anonymous. Would anyone like to share examples of applications that are using MonetDB ?
Regards,
Jeremy
Hello,
The log file, merovingian.log, contains many occurrences of the below:
2011-10-21 17:20:47 ERR discovery[4680]: error while sending broadcast message: Network is unreachable
The database seems to be performing ok. What causes this issue, would this affect the performance of the database ?
Regards,
Jeremy