users-list January 2012

users-list@monetdb.org

22 participants
23 discussions

[MonetDB-users] MonetDB JDBC 1.9 question

by Charalampos Nikolaou

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

10 years, 5 months

[MonetDB-users] How can I execute SQL via mclient directly?

by bai dongli

Hi guys, I'm pretty new for Monetdb, As per the introduce of the online document, I have to type the password on the command line window when I want to execute SQL via the mclient program. It there a way like this which can be used in Mysql: "mysql --user --password databasename -e SQL" in monetdb? I didn't found the argument that can used for the "password" in mclient. Thanks, Tony

10 years, 5 months

[MonetDB-users] size of table

by Pavel Stehule

Hello I can't to search in doc a way to get size of tables. Is there some function or statement how to do it? Thank you Pavel Stehule

10 years, 6 months

[MonetDB-users] Best backup strategy

by Sékine Coulibaly

Hi there, Thanks again for your last replies regarding the insertion into base. Using COPY INTO worked like a charm. A production deployment means : - Backup - High availability So my questions here, not addressed in the online docs are : - Regarding backup, is there a way to make a consistent backup (I mean putting the DB in a "backuping state", and save/archive the files) - To allow for high availability, can I use clusterization ? Can horizontal scalability be achieved through clusterization ? Thank you !

10 years, 6 months

[MonetDB-users] Announcement: New Dec2011 Feature release of MonetDB suite

by Sjoerd Mullender

The MonetDB team at CWI/MonetDB BV is pleased to announce the Dec2011 feature 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/>. Dec 2011 feature release SQL * mclient: The csv output format can now also be of the form csv=c and csv+c where c is the column separator. The form with csv+ produces a single header line with column names. * Changed a bug where the sign() function returned the same type as its argument instead of always an INTEGER. * Added a fix for bug #2834, which caused weird (failing) behaviour with PreparedStatements. * Fixed a bug when using default values for interval columns. Bug 2877. * A bug was fixed where deleted rows weren't properly accounted for in all operations. This was bug 2882. * A bug was fixed which caused an update to an internal table to happen too soon. The bug could be observed on a multicore system with a query INSERT INTO t (SELECT * FROM t) when the table t is "large enough". This was bug 2883. Java Module * Implemented getMetaData() method of PreparedStatement. * Fixed an AssertionError for special results from e.g. EXPLAIN queries. * Fixed overflow error when batching large statements, bug #2952 * Resolved a concurrency problem where ResultSet's date-related getters could cause odd stack traces when used by multiple threads at the same time, bug #2950. * JDBC now implements JDBCv4.1 which makes it possible to be built with Java 7 and up. JDBCv4.1 is a maintenance release of JDBCv4, and hence can be compiled with Java 6, although the added methods obviously are not part of the java.sql interfaces. * SQLExceptions thrown now carry a SQLSTATE. Until the server starts sending correct SQLSTATEs for all errors, server originated errors without SQLSTATE are considered generic data exceptions (22000). * Fixed a bug where closing ResultSets and PreparedStatements could lead to errors on concurrent running queries using the same Connection due to a race condition. * Changed version scheme of JDBC driver and MCL jar to be more standard, from monetdb-X.Y-<thing>.jar to monetdb-<thing>-X.Y.jar, bug #2943 * The embedded monet instance capability of MonetConnection was removed. * Bump JDBC version to 2.0 (Liberica). JDBC now implements JDBCv4 which makes it possible to be built with Java 6 and up. Java 5 and before are no longer supported, and can use the 1.x releases of the driver. * INTERVAL columns are now treated as decimals, since they can have sub-second precision. Client Package * Fix making connections with stethoscope to hosts without monetdbd. Bug #2944. * Fixed some bugs in the PHP interface affecting the mapi_ping(), monetdb_insert_id() and auto_commit() functions. Bugs #2936, #2937, #2938. * ODBC: Fixed SQLNumResultCols and SQLDescribeCol to return useful information after a call to SQLPrepare and before any SQLExecute. * mclient: The exact interpretation of the -i (--interactive) option and the - filename argument have changed. The - filename argument means read from standard input and no longer implies that no \ interpretation is done on the input. Instead, \ interpretation is done if either standard input is a terminal, or if the -i option is given. The -i option no longer causes mclient to read from standard input. It only means to do \ interpretation when reading from standard input. Use the - filename argument to read from standard input. Note that if no -s option is specified and no filename arguments are present, mclient still reads from standard input. * ODBC: Improved internal query for SQLSpecialColumns. Before, the query returned all columns taking part in a PRIMARY KEY *and* all columns taking part in a UNIQUE constraint. Now it returns only one or the other set. * ODBC: The database name is now used as the catalog name throughout. Functions that return a catalog name return the database name, and functions that match on catalog name match it with the database name. * ODBC: Implemented an easier way to create a log file of interactions with the ODBC driver. You can now add a connection attribute "LOGFILE=filename" to the connection string parameter of SQLBrowseConnect and SQLDriverConnect, and to the relevant part of the Windows registry or odbc.ini file. This value is only used if there is no environment variable ODBCDEBUG. * Quoting of object names for mclient's \d command is now more flexible and consistent with standard SQL quoting rules, bug #2846. * ODBC: Implemented SQLColumnPrivileges function. * Install new program, mnc, which provides netcat functionality, but based on MonetDB's communication libraries * Report full URI to database instead of just database when available in mclient. * The time format of the timer output can now be controlled with an optional argument to the -i option. ms, s and m force the time to be formatted as milliseconds, seconds or minutes + seconds respectively. * 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 * Fixed Perl DBD rowcount for larger results, bug #2889 * Perl: We now distinguish properly between TABLE and GLOBAL TEMPORARY (the latter are recognized by being in the "tmp" schema). * Perl: fixed a bunch of syntax errors. This fixes bug 2884. With thanks to Rémy Chibois. * Perl: Fixed DBD::monetdb table_info and tabletype_info. This fixes bug 2885. With thanks to Rémy Chibois. * mclient: fix display of varchar columns with only NULL values. * Fixed a bug in mclient/msqldump where an internal error occurred during dump when there are GLOBAL TEMPORARY tables. MonetDB5 Server * A couple of memory leaks have been plugged. * Introduced new variable max_clients that allows to define how many concurrent connections are allowed to be made against the database. * mal_interpreter.mx Protect against concurrent exceptions If multiple parallel blocks access the exception variables and perform GDKfree on old messages, then we may enter a case that one thread attempts a second free. Simple lock-based protection is the first line of defense. * bpm and partitions have been moved to the attic. It is replaced by the partition optimizer, still under construction. * The MAL debugger next/step operations semantics have been fixed. The profiler also now clearly shows entrance/exit of a MAL function. * The dataflow optimizer uses a less strict side-effect test for BAT new operations and better recognizes trivial plans. * Fixed a problem where MAL variables weren't properly cleared before reuse of the data strucutre. This problem could cause the data flow scheduler to generate dependencies between instructions that didn't actually exist, which in turn could cause circular dependencies among instructions with deadlock as a result. Bugs 2865 and 2888. Merovingian * Fixed crash in monetdb when an invalid property was retrieved using the get command, bug #2953. * monetdb get output is now grouped by database instead of by property * Unlike in previous releases, 'monetdbd get mserver' now returns the path to the mserver5 binary only for dbfarms that have a running monetdbd, instead of only for those that are not served by a monetdbd. * Add nclients property that controls the maximum number of concurrent clients allowed to access the database * Starting monetdbd without any arguments or without dbfarm is no longer supported. A dbfarm now must be provided for each command. * The control passphrase has been turned into a hash of the password, for a more stronger authorisation model as used by mclients. On upgrade, any existing passphrase is converted to the hashed version of the passphrase. * The monetdbd controlport option has been removed in favour of a boolean control option. On upgrade, when controlport was set to a non-zero value and a passphrase was set, control is set to true, or false otherwise. * The monetdbd discoveryport option has been removed in favour of a boolean discovery option. On upgrade, when discoveryport was set to a non-zero value, discovery is set to true, or false otherwise. * Fixed a bug where monetdbd's socket files from /tmp were removed when a second monetdbd was attempted to be started using the same port. * 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. MonetDB Common * Fixed memory detection on 32-bits Solaris systems with more memory than can be addressed in 32-bits mode, bug #2935 Bug Fixes

10 years, 6 months

[MonetDB-users] measure performance time

by jfergar

Hi, I need to measure the sql query execution time of several queries. The mclient "-t" option does not exist in the newer version, and the "\< file_with_queries" SQL command does not seem to show the time when importing from a file. Any ideas?? -- View this message in context: http://old.nabble.com/measure-performance-time-tp33201681p33201681.html Sent from the monetdb-users mailing list archive at Nabble.com.

10 years, 6 months

[MonetDB-users] Strange disk I/O behavior

by Viktor Rosenfeld

Hi, I'm observing disk I/O when evaluating some queries which I am unable to explain. I have two datasets, one relatively small with the BATs taking up 1.6 MB on disk and one fairly large with 283 MB on disk. According to iostat, when I evaluate the attached query on the small dataset, 100 MB are written to disk, but none are read. This is on a Linux machine with 4 GB RAM running the Aug2011-SP3 release. I don't understand why data is written on disk, that (a) is never read again and (b) would easily fit into main memory. I am unable to evaluate the queries on the large dataset because MonetDB writes so much data that the disk fills up after a few minutes (more than 22GB). Please let me know if I can provide more information. Cheers, Viktor

10 years, 6 months

[MonetDB-users] MonetDB to X100 relations

by Pavel Stehule

Hello I am interested about current state of MonetDB/X100 project? It is freely available? It is part of current MonetDB 5 project? Can we expect some progress and possible availability under some open source licence? Thank you for information Best regards Pavel Stehule

10 years, 6 months

[MonetDB-users] ODBC Error

by Luiz Gustavo de Souza

Greetings MonetDB developers! I'm preparing MonetDB for an application, and I got the current error from the ODBC: [MonetDB][ODBC Driver 11.5.9]Cannot return the number of output columns. Query must be executed first. I'm using Windows 7 Ultimate 64bits with both ODBC x86 and x64, but the system and also the Microsoft Excel only find the x86 driver. How can I overcome this? Thank you very much.

10 years, 6 months

[MonetDB-users] Slow import from a SQL (20 tps)

by Sékine Coulibaly

I'm evaluating MonetDB and importing an SQL file containing INSERT statements, so that I can populate the following table : CREATE TABLE session ( cmd character varying(25), date bigint, session_id character varying(64), score integer, src_ip character varying(25), dst_ip character varying(25), tx_bytes integer, rx_bytes integer, retx_bytes integer, scrambling character varying(16), url character varying(64), country character varying(32), orig character varying(3), status integer ) No index was created. >From what I can see, I'm somewhere between 20 and 40 insertions per second (Core i5, 4GB RAM, Windows7, MonetDb MonetDB5-SQL-Installer-i386-20111021.msi). The Windows task manager shows a disk write throughput of 300 kB/s which looks like very small, processor usage around 5%. I imported the file with mclient -u monetdb < myfile.sql I expected to import at 200 rows/second minimum. Am I doing something wrong ? What can be done to improve the loading speed ? Thank you SC

10 years, 6 months

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users-list January 2012