- users-list - monetdb.org

[MonetDB-users] speed comparison off inserts and deletes, and db size question
by Quartz 03 Aug '05

03 Aug '05

Hi, I'm not too familiar with the BAT concept. Regardless, I want to know more about the SQL equivalents. We have need for a 300 million recors DB of about 500 GB. We insert about 1000 records per seconds. or about 100 millions record per day, for 3 days. We 'roll' the data by time, deleting the tail end of the tables, but the the 'deletes' are too slow. So, we are looking at better DB or data storage patterns (one that would allow a quick DROP-table-like or file.delete() response time). So, as I look at MonetDB, I have some questions: 1-What is the insert speed relatively to other DBs? 2-What is the delete speed relatively to other DBs? 3-What is the insert speed degradation with the addition of indexes? 4-What is the delete speed degradation with the addition of indexes? Also, in the forum, I saw some discussions about size. We may remain on a 32 bits kernel, so: 5-The 2 gigs limit on BATs, is that records count is byte size? A performance constraint was also highlighted: "the performance degradation starts when MonetDB has to access BATs larger then the available memory" 6-In our case, with 300 millions records, how big would be the BATs? Last question, lucky 7: 7-Do you think MonetDB is at all a good choice for our high-thoughput highly volatile data? Thanks! ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs

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[MonetDB-users] Using MonetDB for financial time series analysis
by Joel Reymont 28 Jul '05

28 Jul '05

Howdy! I'm looking to use the framework for high-performance storing and querying of financial time series, i.e. ticks arriving from the exchange. I need to be able to store 500-1000 (or more) ticks per second and would like to be able to quickly find similar time series given a date range. I'm looking to create a cheaper alternative to www.kx.com with their KDB and K language. For each tick I need to store the datetime, symbol, trade type (bid/ask/trade), price and volume. How would I do a similarity search? I would like to select a portion of my stock chart (for example) and find subsequences in other stocks that match the pattern. What is the best way to take differences in scale be taken into account? Would I need to calculate the Euclidian distance myself? If I am to write wavelet or Fast Fourier Transform code, should I write it in MIL or use the Python/Perl/etc interface? Thanks for your help and please use the link in my signature to read up on my project. Thanks, Joel -- http://wagerlabs.com/uptick

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[MonetDB-users] Triggers in MonetDB
by Arthur van Bunningen 17 Jul '05

17 Jul '05

Dear all, First my compliments with this piece of useful and implemented research. Second I was wondering if there is a possibility to have so-called "triggers" in MonetDB such as in for example PostgreSQL [1] or if there are other ways to use MonetDB as an "active database". If anyone has experiences in this field or can point me to the right place to look for this experience I would be very thankful. Kind regards, Arthur van Bunningen [1] http://www.postgresql.org/docs/8.0/static/triggers.html -- Ir. A.H. van Bunningen - PhD Student, Data Management Technology Univ. of Twente, Dept of EEMCS, POBox 217, 7500 AE Enschede, Netherlands Email: bunninge(a)cs.utwente.nl, Phone: +31 53 489 4290, Room: ZI3061 WWW: http://www.cs.utwente.nl/~bunninge

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[MonetDB-users] jdbc related tests fail with a : connection refused
by Arnold Reuser 16 Jul '05

16 Jul '05

Hi all, Currently I've installed MonetDB & SQL on SUSE9.2 Pro from source as it was in CVS on 15 July. The problem I have is that all my jdbc related tests fail with a : Database connect failed: Unable to connect (localhost:48016): Connection refused , MServer with sql option and MapiClient runs just fine. Another example : % java -jar share/MonetDB/lib/MonetDB_JDBC.jar -umonetdb password: <monetdb> Currenlty also fails with the given username, password. Is the documentation or are the tests outdated? Or is there something I should be aware of before I can run the java part correctly. My main focus for MonetDB is also the usage of SQL by using a JDBC connection, therefore I hope this isn't a known newbie problem. cheers, Arnold

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[MonetDB-users] bogus SQL in example + bad Mapi error reporting
by Martijn Faassen 03 Jul '05

03 Jul '05

Hi there, I just spent several hours scratching my head over why a piece of code didn't work. I was experimenting with Mapi and tried the example listed on the top of this page: http://monetdb.cwi.nl/TechDocs/APIs/Mapi/C/index.html This contains the following line: if ((hdl = mapi_query(dbh, "create table emp(name varchar, age int)")) == NULL) die(dbh); Unfortunately, it needs to be 'varchar(20)', not just plain 'varchar'. Just 'varchar' apparently does *not* result in an error, but instead all subsequent insert operations plus the select operation do nothing whatsoever; the fetching returns no results at all. The combination of this very bad error reporting and the mistake in the very first example given on the C API page cost me quite a bit of time, so I'm slightly grumpy. :) The bad example given is not good, but the way the error appears to be completely ignored is worse; this is not good for debuggability. The combination is terrible and not particularly conductive to the uptake of MonetDB. It may be of course that this bug is already fixed in CVS; I'm working off the latest release. Anyway, now that my test code finally works, I can hopefully make some progress hooking up XQuery to a Python API. (this is an experiment, and I realize the existing Python Mapi client code already ought to work, but we'll see..). Regards, Martijn

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[MonetDB-users] mapi and xquery
by Martijn Faassen 03 Jul '05

03 Jul '05

Hi there, I'm trying to figure out how to use mapi to do an xquery. I have been able to shred documents (using MIL), but mapi with xquery is giving me trouble. Looking at the implementation of MapiClient, I see the following piece of code which appears relevant: /* xquery options are passed via the command string (becomes first line of query) */ char *c = command ? command : XQuerydefaultMode; char *t = strstr(c, "timing-") ? "" : mark ? "timing-" : ""; char *d = strstr(c, "debug-") ? "" : trace ? "debug-" : ""; char *m = strstr(c, "-mapi") ? "" : "-mapi"; command = (char*) malloc(strlen(c) + 20); sprintf(command, "%s%s%s%s\n", t, d, c, m); as well as this code: if (command) { /* special code for XQuery: prepend command to query */ hdl = mapi_query_prep(mid); CHECK_RESULT(mid, hdl, buf, break); mapi_query_part(hdl, command, strlen(command)); what exactly is going on here? The logic is rather opaque... Is there some minimal code example somewhere out there that shows how to do an xquery using mapi? Regards, Martijn

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[MonetDB-users] xquery collection support?
by Martijn Faassen 02 Jul '05

02 Jul '05

Hi there, Another question: does the xquery implementation have collection support? It appears not, as fn:collection doesn't appear to be supported yet, but I'm a newbie to xquery so I may be missing something. I'm interested in XML content management applications, which tend to keep lots (and lots) of smaller XML documents. It'd be interesting to be able to query all of them (or sets of them) using XQuery in one go -- looping through all the stored documents and doing an XQuery on these individually would be suboptimal. Regards, Martijn

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[MonetDB-users] monetdb failing tests on FreeBSD
by Joseph McDonald 09 Jun '05

09 Jun '05

Hi, I just installed MonetDB-4.8.0_rc0 on FreeBSD 5.4-STABLE running on an opteron. To get it to compile I added this to monetdb_config.h: #define __BSD_VISIBLE 1 and I changed /* #define _POSIX_C_SOURCE 200112L */ /* XXX JOE */ #define _POSIX_C_SOURCE 200112 because a freebsd system header already had _POSIX_C_SOURCE defined without the L. when running "gmake check" I get: !ERROR: Testing FAILED SIGNIFICANTLY ! 2 out of 69 tests could not be executed 2 out of 69 tests produced slightly different output 2 out of 69 tests produced SIGNIFICANTLY different output the output is at http://theoden.vpop.net/~joe/mtest/ Any idea what this means and why? I am brand new to monetdb. thanks, -joe

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[MonetDB-users] running 'make check'
by Martijn Faassen 07 Jun '05

07 Jun '05

Hey, Thanks to Niels Nes, my compilation problems were solved. Just for others who may be reading: it was a bogus mel.yy.cc that I generated on an early compile run without bison and flex installed, and this didn't get removed by 'make clean' (something that will be fixed). Anyway, now I ran 'make check', but not very successfully: !ERROR: Testing FAILED SIGNIFICANTLY ! 3 out of 222 tests could not be executed 219 out of 222 tests produced SIGNIFICANTLY different output Basically typically the output I'd see was like this: 14:56:39> tests/suite_06/test_02.milS (<=60,60,60) ... 0.103s (Killed!) test_02.stable.out.FILTERED and test_02.test.out.FILTERED are equal. test_02.stable.err.FILTERED and test_02.test.err.FILTERED differ SIGNIFICANTLY! 14:56:40> tests/suite_08/test_01.milM (<=60,60,60) ... 0.126s (Killed!) test_01.stable.out.FILTERED and test_01.test.out.FILTERED are equal. test_01.stable.err.FILTERED and test_01.test.err.FILTERED differ SIGNIFICANTLY! 14:56:41> tests/suite_08/test_02.milS (<=60,60,60) ... 0.120s (Killed!) test_02.stable.out.FILTERED and test_02.test.out.FILTERED are equal. test_02.stable.err.FILTERED and test_02.test.err.FILTERED differ SIGNIFICANTLY! Looking at the HTML output, one set of unexpected output looks to be option information like this: # builtin opt config = ${prefix}/etc/MonetDB.conf # builtin opt gdk_arch = 32biti686-pc-linux-gnu # builtin opt gdk_version = 4.8.0 # builtin opt monet_pid = 30545 # builtin opt prefix = /home/faassen/tmp/local # builtin opt exec_prefix = ${prefix} # builtin opt gdk_dbname = tst # builtin opt gdk_dbfarm = ${prefix}/var/MonetDB More seriously, I get this: ! /home/faassen/working/monet/MonetDB-4.8.0/src/tools/Tests:: No such file or directory ! All: No such file or directory ! client.milC: No such file or directory ! client.stable.err: No such file or directory ! client.stable.out: No such file or directory ! client.stable.out.64bit: No such file or directory ! client.stable.out.64bit.monet_nostalgic.: No such file or directory ... etc Strangely enough, the directory mentioned does exist: faassen@moon:~$ cd /home/faassen/working/monet/MonetDB-4.8.0/src/tools/Tests faassen@moon:~/working/monet/MonetDB-4.8.0/src/tools/Tests$ pwd /home/faassen/working/monet/MonetDB-4.8.0/src/tools/Tests and those files, at least at a brief glance, do seem to exist too. Again I guess I'm missing something somewhere.. Regards, Martijn

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[MonetDB-users] MonetDB 4.8.0 compile problem
by Martijn Faassen 03 Jun '05

03 Jun '05

Hi there, I'm trying to get MonetDB compiled on my debian (unstable) box, but I keep running into the same snag. It's probably something stupid, but I cannot seem to solve it. The full error log is in the end, but much of it seems to point to a missing yacc/bison during linking: mel.o(.text+0x6f4): In function `main': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.mx:400: undefined reference to `yyin' mel.tab.o(.text+0x126): In function `yyparse': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:53: undefined reference to `yylineno' I have bison and flex installed, and configure picks it up, but this doesn't seem to help any... Does anyone have any clue on what I am doing wrong here, and how to fix it? Regards, Martijn /bin/sh ../../libtool --tag=CXX --mode=link g++ -g -O2 -ansi -Wall -W -o mel FileInfo.o atomops.o mil.o prelude.o bat_arg.o epilogue.o var_arg.o proto.o builtin.o glue.o mel.o mel.tab.o mel.yy.o symbol.o command.o html.o module.o symtable.o any_arg.o debug.o iterator.o object.o type_arg.o atom.o depend.o operator.o use.o atom_arg.o dependency.o link.o ops.o g++ -g -O2 -ansi -Wall -W -o mel FileInfo.o atomops.o mil.o prelude.o bat_arg.o epilogue.o var_arg.o proto.o builtin.o glue.o mel.o mel.tab.o mel.yy.o symbol.o command.o html.o module.o symtable.o any_arg.o debug.o iterator.o object.o type_arg.o atom.o depend.o operator.o use.o atom_arg.o dependency.o link.o ops.o mel.yy.o(.text+0x0): In function `main': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy.cc:2: multiple definition of `main' mel.o(.text+0x670):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.mx:388: first defined here /usr/bin/ld: Warning: size of symbol `main' changed from 1247 in mel.o to 15 in mel.yy.o mel.o(.text+0x6f4): In function `main': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.mx:400: undefined reference to `yyin' mel.tab.o(.text+0x126): In function `yyparse': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:53: undefined reference to `yylineno' mel.tab.o(.text+0x138):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:54: undefined reference to `yyin' mel.tab.o(.text+0x1e0):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:61: undefined reference to `yylineno' mel.tab.o(.text+0x265):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:64: undefined reference to `close_and_change(void*, _IO_FILE*)' mel.tab.o(.text+0x621):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:124: undefined reference to `get_cur_buffer()' mel.tab.o(.text+0x637):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:125: undefined reference to `yylineno' mel.tab.o(.text+0x691):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:129: undefined reference to `new_buffer(_IO_FILE*)' mel.tab.o(.text+0x99f):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:181: undefined reference to `get_signature(char*)' mel.tab.o(.text+0x9c0):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:182: undefined reference to `script' mel.tab.o(.text+0x15dc): In function `yyparse': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/y.tab.c:1168: undefined reference to `yylex()' mel.tab.o(.text+0x176b): In function `mel_yyerror(char const*)': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:464: undefined reference to `yylineno' mel.tab.o(.text+0x178c): In function `mel_yyerror(char const*)': /usr/include/c++/3.3/ostream:193: undefined reference to `yylineno' mel.tab.o(.text+0x17da): In function `mel_yyerror(char const*)': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:468: undefined reference to `yytext' mel.tab.o(.text+0x17f3):/home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:472: undefined reference to `yytext' mel.tab.o(.text+0x1876): In function `mel_yyerror(char const*)': /usr/include/c++/3.3/ostream:193: undefined reference to `yytext' mel.tab.o(.text+0x195b): In function `semerror()': /home/faassen/working/monet/MonetDB-4.8.0/src/mel/mel.yy:494: undefined reference to `yylineno' mel.tab.o(.text+0x197c): In function `semerror()': /usr/include/c++/3.3/ostream:193: undefined reference to `yylineno' collect2: ld returned 1 exit status make[4]: *** [mel] Error 1 make[4]: Leaving directory `/home/faassen/working/monet/MonetDB-4.8.0/src/mel' make[3]: *** [all] Error 2 make[3]: Leaving directory `/home/faassen/working/monet/MonetDB-4.8.0/src/mel' make[2]: *** [all-recursive] Error 1 make[2]: Leaving directory `/home/faassen/working/monet/MonetDB-4.8.0/src' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/home/faassen/working/monet/MonetDB-4.8.0' make: *** [all] Error 2

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[MonetDB-users] Converting a unix timestamp (bigint) to timestamp/date?
by Arjen van der Meijden 24 May '05

24 May '05

Hi List, I'm trying to have an easy way to convert some fields that where initialy (in MySQL) stored as unsigned integers. I converted them using a dump/restore to MonetDB's bigint. Currently this works: CAST("1970-01-01 01:00:00" as timestamp) + (CAST(RecordTimestamp AS STRING) || 'LL') Appearantly bigint (long) is incompatible with sec_interval (long)? But afaik this should be possible in SQL as well: CAST("1970-01-01 01:00:00" as timestamp) + INTERVAL RecordTimestamp SECONDS And of course in MySQL there is FROM_UNIXTIME(RecordTimestamp), in PostgreSQL there is: timestamp 'epoch' + RecordTimestamp * interval '1 seconds' Converting it back is also quite a bit of work: SELECT ((CAST(current_timestamp as timestamp) - CAST("1970-01-01 00:00:00" as timestamp)) / 1000); That seems to work to get the current time's epoch... Why aren't timestamptz and timestamp compatible, btw? In MySQL there is UNIX_TIMESTAMP(RecordTimestamp), in PostgreSQL EXTRACT(epoch FROM current_timestamp)::bigint I was also looking for a way to format the date/timestamp output, is that possible? Casting it to a SQL-date is rather easy of course, but other formatting will very likely become a big mess if EXTRACT where to be used. Since my client-language is php, I either need preformatted output or a unix timestamp for ease of use. In SQL it is often better to work with dates/timestamps, rather than the not really correct unix timestamp arithmetics (add 86400 seconds to get the next day and so on). Did I overlook some easy to use extentions to SQL, or do I really need to use the constructs I already found? Best regards, Arjen van der Meijden

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[MonetDB-users] Bug with average of decimals when an empty table is returned
by Arjen van der Meijden 24 May '05

24 May '05

Hi list, I noticed a weird result from AVG when doing one of my queries; -1.7976931348623158e+307 Appearantly it happens with this minimal testcase: monetdb-> create table emptyone (field decimal(3,1)); Operation successful monetdb-> select avg(field) from emptyone; +------------------------+ | scale_down_avg_field | +========================+ | -1.7976931348623158E307 | +------------------------+ 1 row The result should afaik be NULL, not this value. With a decimal(3) it works correctly by the way. The same behaviour is seen with numeric(3,1) vs numeric(3). Best regards, Arjen

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[MonetDB-users] Re: MonetDB Questions
by Martin Kersten 17 May '05

17 May '05

Hello Mason, thank you for your interest in using MonetDB. Enclosed a quick response to your questions. If I miss something, someone from the monetdb-users list is likely to fill in the details. M Sharp wrote: > Hello Martin, > > We are interested in evaluating MonetDB for use with our product (a > potential customer of ours told us queries ran 5-6 times faster than on That;s what we know to be true for especially decision support applications. > PostgreSQL). Basically we would install MonetDB on several nodes, and > partition data amongst them, for data warehousing usage (more info about > our product can be found at http://www.extendb.com) > > I have looked through the documentation and website, but have some > questions I was hoping you could help answer (as the project lead). If > it is not too much trouble, I would greatly appreciate it if you could > take a few minutes to answer. > > 1. Size limitation. If I understand correctly, there is no size > limitation for tables or databases, just that a single column is limited > to 2 GB. Is that correct? Also, when do you believe this restriction > will be removed? The size limitation of 2 GB holds for 32-bit platforms, it is already removed for 64 bit machines. > > 1a. I see something in the config file about 3GB of virtual memory. If > the database (or table) is larger than that, does it negatively impact > performance? The performance degradation starts when MonetDB has to access BATs larger then the available memory, but won;t become slower than what you would expect in traditional database systems. The judicious use of the BATs mean that in practice of decision support you have a much lower chance hitting an IO bottleneck. > > 2. Multiple databases. I noticed in the config file that only one > database can be used at a time. Can we start mulitple MonetDB instances > to support multiple databases, just using a different port? There can be one Mserver per database directory, and ofcourse multiple Mserver instances per platform. > > 3. Backups. Is there any backup tool? Also, can you do incremental > backups? No, we are looking forward to people interesting in developing such supportive tools. > > 4. Is there point in time recovery? The SQL frontend ensures a log of all committed transactions to ensure stability. If you use the system at the MIL layer you have to schedule that work yourself. > > 5. Do you support savepoints (or subtranscations), not just > transactions? The SQL transaction semantics is based on the requirements in SQL99 > > 6. What kind of locking capability is offered; DB, table or row? Are > there different isolation levels? There are no separate isolation levels. The policy in MonetDB is to assume a cooperative environment, which means that (SQL) compilers have to explicity lock/release resources to support concurrent use from clients. Internally, the system is fully configured to safely run with tens of concurrent threads thereby protecting the integrity of the database structures (but not their content). > > 7. Is there a separate high-speed loader utility, or must INSERTs be > used? yes there is. > > 8. Are checkpoints used? And is it configurable? No particular support for taking a checkpoint > > 9. Are there utilities by which you can determine corruption? ... And > repair corruption? The additional tools have not been needed so far. The SQL log was sufficient to deal with the rare cases during development crashes. > > > > Thank you very much in advance for taking the time to answer these > questions. Also, please feel free to provide any other thoughts you have > regarding using MonetDB and handling large databases (~ 1 TB). It is the sizes we are after, but not on 32-bit platforms. > > Regards, > > Mason Sharp > ExtenDB >

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[MonetDB-users] VOIDs and multiple BATs
by Edmund Dengler 09 May '05

09 May '05

Greetings! Just doing some more digging around MonetDB, and have a couple of questions. (1) If I am managing multiple BATs that are (supposedly) synced, how do I manage appends and the syncing? For example, I have a_p1 = BAT[void, int] and a_p2 = BAT[void, int] (a_p1 = <a> type things with property p1) (a_p2 = <a> type things with property p2) I wish to insert a new <a>=(1,2) thing. Do I do? bat("a_p1").append(1); bat("a_p2").append(2); How do I ensure that the "voids" are always synced? Is this just "assumed"? What if I fail in the middle of operations (such that a_p1 has an extra row) and stuck with dirty tables? Do I do a global "abort();" or a "clean();" to get back to a safe state? Will this reset the seqbase? (Is this documented someplace? I am trying to look at the architecture docs but cannot find anything that concretely answers similar questions.) (2) How does sync() work? Do I do a: sync(bat("a_p1"), bat("a_p2")); once and only once? After every update/append to the tables? There is the phrase "When two BATs effectively contain the same sequence of head elements, we call them 'synced'. This is implemented by storing a very large OID for each column. An update to the column destroys this OID.". This sounds as if any update/append breaks the correspondence, and also that it will limit the number of rows in the table (as an OID is a 32-bit number of 32-bit systems). If I have 10 properties I am tracking, would I pick one as the "primary" BAT, and sync() all others to it? Regards! Ed

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[MonetDB-users] Counting open BATs
by Edmund Dengler 05 May '05

05 May '05

Greetings! In the architectural overview, I find the text: "Most memory resource problems in MonetDB are easily avoidable by minimizing your open BAT references (as discussed above) and making your access patterns cache friendly (see the radix module)." Is there anyplace that actually describes when a BAT is considered open? Is it a scope thing (BATs are closed as soon as they are out of scope)? Is a BAT open when I append/update? Does it close when I perform a commit? If not, is there a way to specify "I am done, clean it out"? I am noticing a large amount of open memory (approximately 500MB out of a 1GB system) being used by MonetDB. I have hand partitioned my BATs into groups using a naming convention, but I am wondering if during inserts I am somehow keeping open references to the BATs which may cause issues. Is there a way to find out where memory is being allocated? Which BATs are open? Also, I am setting some of the larger BATs to STORE_MMAP. I notice in the documentation that if I compress the heaps, then these must be set to STORE_MEM. Is there a reason that when uncompressing the heap, that the uncompressed version cannot be STORE_MMAP to avoid memory problems? Regards! Ed

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[MonetDB-users] Use of C/C++ prepare statements
by Edmund Dengler 21 Apr '05

21 Apr '05

Greetings! Does anybody have any working example code using mapi_prepare/map_prepare_array/mapi_execute_array showing the use of a prepare along with array substitution? I can get a sample piece working using mapi_execute. Trying mapi_execute_array causes the test program to exit with an error code of 139 (the function does not seem to return, but causes an immediate exit). Using mapi_prepare/mapi_execute_array, the program runs, but nothing is changing in the database. Regards! Ed

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[MonetDB-users] Questions
by Edmund Dengler 21 Apr '05

21 Apr '05

Howdy all! I had posted some questions regarding MonetDB, but have not received feedback on any of them. Is there a more appropriate list I should be posting to? Regards! Ed

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[MonetDB-users] Crashing server
by Edmund Dengler 18 Apr '05

18 Apr '05

Greetings! Having some problems with the MonetDB server crashing. - Start a server - Have a client perform a lot of operations (_lots_ of BATs creation, bun insertions, etc). - Every 10,000 or so operations, perform a <commit();> on the client. Total operations: approximately 7500 BATs, 17,000,000 BUNs. - Do an <ls();> on the server to confirm all tables are clean. - Now perform an <abort();> on the server with every table clean. MonetDB>abort(); #GDKmmap(6553600) fail => BBPtrim(enter) usage[mem=736705664,vm=2137835808] # !mallinfo.arena = 35753984 !mallinfo.ordblks = 4454 !mallinfo.smblks = 0 !mallinfo.hblkhd = 122863616 !mallinfo.hblks = 33 !mallinfo.usmblks = 0 !mallinfo.fsmblks = 0 !mallinfo.uordblks = 15990816 !mallinfo.fordblks = 19763168 #GDKmmap(6553600) fail => BBPtrim(ready) usage[mem=736705664,vm=2137835808] # !mallinfo.arena = 35753984 ... (and so on) Doing a <ulimit -a> shows: core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited file size (blocks, -f) unlimited max locked memory (kbytes, -l) 32 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 14336 virtual memory (kbytes, -v) unlimited Anybody have any ideas on why the server died? If I do it with less (_much_ less) operations, it at least succeeds (even though there is a lot of I/O occurring). Regards! Ed

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[MonetDB-users] Question about OIDs and scaling
by Christopher Petrilli 31 Mar '05

31 Mar '05

I have been reading about MonetDB for a few days now, and have played around with it some and it seems to solve some of the ultra complex queries that I'd like to do in a time that is amazing. Congrats! One thing, though, that confuses me is some scaling issues. The data set that I'm looking at is potentially in the billions of traditional rows, with about 50 columns, so from my understanding that'd be 50 different BATs each with a billion or more items. My concern is that OIDs seem to be restricted to 2^32-1, although from looking at virtual OIDs, it's unclear whether in my situation that would be useful? Any thoughts on stuffing that much data into the system, especially how it might impact dealing with VM issues? I'm more than happy to say "this is the wrong approach" or system for this problem, as this is obviously a non-normal case. Chris -- | Christopher Petrilli | petrilli(a)gmail.com

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[MonetDB-users] Bulk load to MonetDB
by Juan José van der Linden 24 Mar '05

24 Mar '05

Hi, I've compiled MonetDB and the SQL front-end on my PowerMac 2x2 G5. I've used fink to install the libraries needed. I would like to perform the query test that are available from http://benchw.sourceforge.net . How can I use the acsii_io module to bulk load the data files from the benchw project? Thanks in advance. Regards, Juan José.

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[MonetDB-users] Compilation issue on OS X Panther
by Fabian 20 Mar '05

20 Mar '05

(I am not the one with the problem here, but reporting on behalf to stick to the protocol. Please ignore your user agent's default reply to address and send replies to the list, not to me.) The following build error appears for a user that compiles on a Mac: gcc -g -O2 -std=c99 -Wall -W -Werror-implicit-function-declaration -Werror -Wno-format -Wno-unused-function -Wno-unused-label -Wno-uninitialized -D_REENTRANT -o .libs/MapiClient MapiClient.o ReadlineTools.o -L/sw/lib ./.libs/libMapi.dylib /Users/rvjansen/Desktop/MonetDB/src/common/.libs/libstream.dylib -lreadline ../../../common/.libs/libmutils.dylib ../../../common/.libs/libstream.dylib /Users/rvjansen/Desktop/MonetDB/src/common/.libs/libmutils.dylib -lz /sw/lib/libiconv.dylib ld: Undefined symbols: _BZ2_bzclose _BZ2_bzflush _BZ2_bzopen _BZ2_bzread _BZ2_bzwrite make[7]: *** [MapiClient] Error 1 make[6]: *** [all] Error 2 make[5]: *** [all-recursive] Error 1 make[4]: *** [all-recursive] Error 1 make[3]: *** [all] Error 2 make[2]: *** [all-recursive] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 The user's tools versions: automake 1.9.3 aclocal 1.9.3 autoconf 2.59 libtool ? (there is no --version: default Apple distribution one)

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[MonetDB-users] [Fwd: Re: cvs lock]
by Fabian 20 Mar '05

20 Mar '05

Here find attached the config.status file of the OSX compilation issue. about the mailing list settings stuff (which should be off the list, IMHO): there is a weird distinction between what developers think is useful and what users think is useful. For the sourceforge/Mailman case it seems to me that the former one is considered instead of the latter, which is -- if you expect users to use it -- a wrong assumption. Since SF is made for developers (you have to have a developers account for instance), SF is clearly NOT the place for user interaction. Proof of this theorem can be found in many projects that host a forum like structure on their main website, that often allows guest posting, which is clearly geared towards user usability. (how big do you want to have the barrier that prevents someone from reporting a problem today?)

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[MonetDB-users] SQL Support
by Smits.Dolf 08 Mar '05

08 Mar '05

Hi, I downloaded and installed version 4.6 and am adapting some SQL scripts to the preferred syntax from MonetDB. However, I cannot find any document about what features are implemented, and what is not yet ready. for example, the "if exists" clause, using when dropping a table seems not to be supported. Is any documentation available on the supported syntax, datatypes etc? Thanks, Regards, Dolf Smits Dolf Smits Senior Consultant Meta Directory Solutions Siemens Nederland N.V. Siemens Business Services Bezoekadres Prinses Beatrixlaan 26 Den Haag Correspondentieadres Postbus 16068 NL-2500 BB Den Haag 070 333 3654 070 333 2511 06 55844837 Dolf.Smits(a)siemens.com www.siemens.nl Deze e-mail is uitsluitend bedoeld voor kennisneming door de geadresseerde(n), en mag niet aan anderen worden doorgestuurd of op andere wijze ter kennis worden gebracht. Indien u niet de geadresseerde bent, verzoek ik u om de afzender te waarschuwen en de e-mail direct te verwijderen/vernietigen. De afzender wijst elke aansprakelijkheid voor (de inhoud van) deze e-mail af.

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[MonetDB-users] questions regarding mil-sql interoperation and savepoint behavior
by Kinzer, Jason M (Jason) 26 Feb '05

26 Feb '05

Hi, I'm exploring Monet, and it's a very pleasant experience. I have a few questions however; please forgive the parade of ignorance that follows: - If one creates persistent void-head BATs via MIL, is there a way to them as columns of a SQL table/view. I noticed the parser had a rule allowing "CREATE VIEW ... AS BATS", but wasn't quite sure how to use it. - Conversely, if one has a set of tables, is there any easy way to find that mapping of columns to bat ids (e.g. so that one can lookup individual bats in MIL)? It appears this information is really only persisted in the log file, is that correct? If so, I assume the only other option would be to have the sql module loaded, and then access the temporary bats it creates that hold this metadata (I didn't notice that the module exported any MIL-accessible functions for grabbing the sql_column data)? - I am wondering how transaction chains are supposed to behave w.r.t. memory consumption. Specifically, I noticed that when executing "savepoint x" in the mapiclient, the heap size of the Monet process climbs almost monotonically upwards - jumping perhaps 350K per savepoint (every tx is completely empty) and hardly falling at all following releases or rollbacks (or even client disconnect for that matter). My understanding is that a savepoint is essentially a child transaction (thus copied from the parent), in which case I'm worried it may not be releasing all resources related to the tx and therefore leaking memory? Or is it simply that monet is allocating additional space from the OS, say for BATs related to the transaction, and this memory is becoming part of the internal pool and thus not being release back to the OS? I'd assume the second except that I thought it would reuse the space so that the heap size would stop climbing after a while, and I never did reach that poi! nt even after 100's of savepoints and an 30-fold increase in heap size. (BTW, I'm running the pre-build MonetDB 4.6.0/SQL 2.6.0 on Win2K). Many thanks for your time, and any responses. Cheers, Jason

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[MonetDB-users] compile on Windows - pthread version
by Michael Schmid 24 Feb '05

24 Feb '05

Hello, i am a new user of MonetDB and want to share my problems and solutions with you. I try'ed to compile the source code version on Windows and run in a problem: the comiler give out an error: can not convert from pthread_t to int ...... After study some source code, and read the history of changes in the pthread distro, i read about changing this structure. I downloaded older versions of the Pthread lib, and finally: it compiles well. But only with pthreads-2004-06-22.exe or older, all newer version give the above error. From the Pthreads news "SNAPSHOT 2004-11-03 ------------------- DLLs produced from this snapshot cannot be used with older applications without recompiling the application, due to a change to pthread_t to provide unique POSIX thread IDs." i guess, this is the reason. You should make a hint in the HowToStart-Win32.txt to this, so that other users dont have the same problem. This problem occors on Win2000 and WinXP, with the the release and the CVS code. Do you have plans to change the code the new pthread_t structure, so that newer versions of the PThread distro can be used? Best regards, Michael Schmid

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