Re: [HACKERS] [pgsql-hackers-win32] Sync vs. fsync during checkpoint

2004-02-15 Thread Florian Weimer
Tom Lane wrote: You can only fsync one FD at a time (too bad ... if there were a multi-file-fsync API it'd solve the overspecified-write-ordering issue). What about aio_fsync()? ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands

Re: [HACKERS] sql_sizing

2004-04-15 Thread Florian Weimer
Chris Bowlby [EMAIL PROTECTED] writes: I've got an issue that I've been trying to track down some results to. I've noticed that on a recent PostgreSQL server that I've been working on has a few relations that do not exist: select relname, relnamespace, reltype from pg_class where relname ~*

Re: [HACKERS] [GENERAL] Performance while loading data and indexing

2002-09-27 Thread Florian Weimer
Tom Lane [EMAIL PROTECTED] writes: We'd be happiest with a filesystem that journals its own metadata and not the user data in the file(s). I dunno if there are any. Most journalling file systems work this way. Data journalling is not very widespread, AFAIK. -- Florian Weimer

Re: [HACKERS] 7.4 Wishlist

2002-12-01 Thread Florian Weimer
correctly, so that I dont have to reorder SQL statements manually in the dump before psql can execute it. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax +49-711-685-5898

Re: [PATCHES] [HACKERS] Patch to make Turks happy.

2002-12-06 Thread Florian Weimer
on the UNIX subsystem of OS/390? ;-) (EBCDIC is a bit, uhm, strange. Only the decimal digits are consecutive the rest is a big mess.) -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax

Re: [PATCHES] [HACKERS] Patch to make Turks happy.

2002-12-07 Thread Florian Weimer
Bruce Momjian [EMAIL PROTECTED] writes: Are you 64-bit s390? The patch is for GNU/Linux on S/390 hardware. This platform is sane and it uses ASCII. Only the traditional UNIX subsystem for OS/390 uses EBCDIC. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart

Re: [HACKERS] why was libpq.so's version number bumped?

2003-01-03 Thread Florian Weimer
the more or less the whole memory image of the server process. On 7.3, this has been fixed. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax +49-711-685-5898

Re: [HACKERS] why was libpq.so's version number bumped?

2003-01-03 Thread Florian Weimer
, and quite a few things break. I wouldn't force users to switch right now. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax +49-711-685-5898 ---(end of broadcast

Re: [HACKERS] why was libpq.so's version number bumped?

2003-01-03 Thread Florian Weimer
: rusfw= SELECT byteain(134512640); byteain - \177ELF\001\001\001 (1 row) rusfw= (Of course, the address varies from machine to machine.) -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw

Re: [HACKERS] non-standard escapes in string literals

2002-05-03 Thread Florian Weimer
Bruce Momjian [EMAIL PROTECTED] writes: Added to TODO: * Allow backslash handling in quoted strings to be disabled for portability BTW, what about embedded NUL characters in text strings? ;-) -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http

Re: [HACKERS] [COMMITTERS] pgsql-server/src include/utils/timestamp.h bac ...

2002-08-04 Thread Florian Weimer
a shame to scan the strings twice: once for length for this buffer overrun protection, and once to parse the line. Are these changes available for 7.2, too? There is at least a DoS potential lurking here. :-( -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart

[SECURITY] DoS attack on backend possible (was: Re: [HACKERS][COMMITTERS] pgsql-server/src)

2002-08-09 Thread Florian Weimer
Florian Weimer [EMAIL PROTECTED] writes: Neil Conway [EMAIL PROTECTED] writes: Thomas can correct me if I'm mistaken, but I believe these changes apply to the new integer datetime code No, it's possible to crash the backend in 7.2, too. And 7.2.1, of course. Let me ask again: Do you plan

Re: [HACKERS] [SECURITY] DoS attack on backend possible (was: Re:

2002-08-11 Thread Florian Weimer
be triggered by mere data, an attacker does not have to be able to send specific SQL statements to the server. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax +49-711-685-5898

Re: [HACKERS] [SECURITY] DoS attack on backend possible (was: Re:

2002-08-11 Thread Florian Weimer
characters and formatting hacks) on the date given, then use the date as part of a SQL query, and PostgreSQL will die? It depends on the checking. If you just check that the date consists of digits (and a few additional characters), it's possible to crash the server. -- Florian Weimer

Re: [HACKERS] [SECURITY] DoS attack on backend possible (was: Re:

2002-08-12 Thread Florian Weimer
that looks like a reasonable date would *not* cause the problem. Yes, but if you just check that the date given by the user matches the regular expression [0-9]+-[0-9]+-[0-9]+, it's still possible to crash the backend. -- Florian Weimer[EMAIL PROTECTED] University

Re: [HACKERS] [SECURITY] DoS attack on backend possible (was: Re:

2002-08-12 Thread Florian Weimer
, ... ; But this requires to be able to send arbitrary SQL commands; just feeding a specially crafted date string usually does not. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax

Re: [HACKERS] [SECURITY] DoS attack on backend possible (was: Re:

2002-08-12 Thread Florian Weimer
exploit this to run arbitrary code. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax +49-711-685-5898 ---(end of broadcast)--- TIP 1

Re: [HACKERS] [SECURITY] DoS attack on backend possible (was: Re:

2002-08-12 Thread Florian Weimer
probably impose a length limit in the frontend that uses the database, but the PostgreSQL documentation does not state that this is a requirement (because the parsers in the backend are so fragile). -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni

Re: [HACKERS] [SECURITY] DoS attack on backend possible

2002-08-19 Thread Florian Weimer
of the database to guarantee data integrety. Obviously, the PostgreSQL developers disagree. If I've got to do all checking in the application anyway, I can almost use MySQL instead. ;-) -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni

Re: [HACKERS] [SECURITY] DoS attack on backend possible

2002-08-19 Thread Florian Weimer
string, yet you still believe that it keeps all the data you store, although this involves much more complex data structures and algorithms. What a strange asymmetry! -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS

Re: [HACKERS] [SECURITY] DoS attack on backend possible

2002-08-19 Thread Florian Weimer
developers. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax +49-711-685-5898 ---(end of broadcast)--- TIP 4: Don't 'kill -9

Re: [HACKERS] [SECURITY] DoS attack on backend possible

2002-08-20 Thread Florian Weimer
. This wouldn't have helped in the current case. The bug is in the datetime parser which translates strings to an external representation, not in the SQL parser. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT

Re: [HACKERS] [SECURITY] DoS attack on backend possible

2002-08-21 Thread Florian Weimer
complex) checks in the frontend. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/ RUS-CERT fax +49-711-685-5898 ---(end of broadcast)--- TIP 6

Re: [HACKERS] @(#)Mordred Labs advisory 0x0003: Buffer overflow in

2002-08-22 Thread Florian Weimer
code which consists just of letters!). See for example: http://cert.uni-stuttgart.de/archive/vuln-dev/2000/10/msg00200.html ASCII-only shellcode for RISC platforms is even harder and might be impossible. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http

Re: [HACKERS] Optimization levels when compiling PostgreSQL...

2002-09-22 Thread Florian Weimer
can't increase it further to -O3 and beyond at a slow/incremental rate. -O3 is usually slower than -O2 because of increased code size due to automatic inlining. With GCC, -O4 etc. are all equivalent to -O3. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart

[HACKERS] Escaping strings for inclusion into SQL queries

2001-08-22 Thread Florian Weimer
in a future version of PostgreSQL and libpq. A sample implementation is provided below, along with documentation. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://cert.uni-stuttgart.de/ RUS-CERT +49-711-685-5973/fax +49-711-685

Re: [HACKERS] Re: Escaping strings for inclusion into SQL queries

2001-08-23 Thread Florian Weimer
. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://cert.uni-stuttgart.de/ RUS-CERT +49-711-685-5973/fax +49-711-685-5898 ---(end of broadcast)--- TIP 5: Have you checked our

Re: [HACKERS] Escaping strings for inclusion into SQL queries

2001-08-30 Thread Florian Weimer
Florian Weimer [EMAIL PROTECTED] writes: We therefore suggest that a string escaping function is included in a future version of PostgreSQL and libpq. A sample implementation is provided below, along with documentation. We have now released a description of the problems which occur when

Re: [HACKERS] Escaping strings for inclusion into SQL queries

2001-08-30 Thread Florian Weimer
are already escaped before escaping them (else major breakage of existing application would occur).. You can't do this automatically because the strings needing escaping are not marked in any way at the moment. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart

Re: [HACKERS] Re: Escaping strings for inclusion into SQL queries

2001-09-03 Thread Florian Weimer
Peter Eisentraut [EMAIL PROTECTED] writes: Florian Weimer writes: The first version escaped ' with ''. I changed it when I noticed that if \' is used instead, the same function can be used for strings ('...') and identifiers (...). Last time I checked (15 seconds ago), you could

Re: [HACKERS] Escaping strings for inclusion into SQL queries

2001-09-04 Thread Florian Weimer
not to use identifiers from an untrusted source at all. Therefore, all claims of the suitability of PQescapeString() for identifiers have been removed. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://cert.uni-stuttgart.de/ RUS-CERT

Re: [HACKERS] Escaping strings for inclusion into SQL queries

2001-09-11 Thread Florian Weimer
string truncation problem occurs). We can't do that, this would require 4n + 1 bytes of storage for the result, breaking the interface. -- Florian Weimer[EMAIL PROTECTED] University of Stuttgart http://cert.uni-stuttgart.de/ RUS-CERT +49-711

Re: [HACKERS] Upcoming re-releases

2006-02-11 Thread Florian Weimer
* Tom Lane: Actually, it's because it's certain to be there and be accessible to unprivileged users. Isn't this a bit problematic because any local user can impersonate a PostgreSQL backend which has been shut down? ---(end of broadcast)--- TIP

Re: [HACKERS] Upcoming re-releases

2006-02-11 Thread Florian Weimer
* Martijn van Oosterhout: Well, I guess it's an issue. At least it's not suceptable to the standard symlink attacks. There is in general no way of knowing if the server you are connecting to is what you think it is (except via SSL maybe?). For local (i.e. UNIX domain socket) connections,

Re: [HACKERS] Upcoming re-releases

2006-02-11 Thread Florian Weimer
* Magnus Hagander: But no, it wouldn't be bad if there was a way to specify exactly which cert is used. Or at least validate the common name of it agains the hostname of the server. SSH-like leap of faith authentication would be even better. Store the certificate on the first connection

Re: [HACKERS] qsort again

2006-02-16 Thread Florian Weimer
* Neil Conway: On Wed, 2006-02-15 at 18:28 -0500, Tom Lane wrote: It seems clear that our qsort.c is doing a pretty awful job of picking qsort pivots, while glibc is mostly managing not to make that mistake. I haven't looked at the glibc code yet to see what they are doing differently.

Re: [HACKERS] possible design bug with PQescapeString()

2006-02-19 Thread Florian Weimer
* Tatsuo Ishii: Users can input value for var from a web form. The attacker inputs following string: (0x95+0x27);DELETE FROM members;-- where 0x95+0x27 is actually a SJIS mutibyte KANJI. Programmer applies PQescapeString() to it and gets: 0x95+0x27+0x27;DELETE FROM members;-- Uh-oh,

Re: [HACKERS] possible design bug with PQescapeString()

2006-02-19 Thread Florian Weimer
* Tatsuo Ishii: Uh-oh, this is my fault. PQescapeString should escape all characters greater than 126. Unfortunately, there is nothing we can do about this in the current function because tha twould need four times the lenggth of the input string (plus one). Drat. Please don't do that.

Re: [HACKERS] Merge algorithms for large numbers of tapes

2006-03-09 Thread Florian Weimer
* Greg Stark: That's one thing that gives me pause about the current approach of using more tapes. It seems like ideally the user would create a temporary work space on each spindle and the database would arrange to use no more than that number of tapes. Then each merge operation would

Re: [HACKERS] Is full_page_writes=off safe in conjunction with PITR?

2006-04-15 Thread Florian Weimer
* Tom Lane: I think we had originally argued that there was no problem anyway because the kernel should cause the page write to appear atomic to other processes (since we issue it in a single write() command). I doubt Linux makes any such guarantees. See this recent thread on linux-kernel:

Re: [HACKERS] Bug in signal handler

2006-05-12 Thread Florian Weimer
* Martijn van Oosterhout: The fact remains that the postmaster has *always* been coded like that, and we have *never* seen any problems. Barring proof that there is a problem, I'm uninterested in rewriting it just because someone doesn't like it. It should probably also be remembered that

Re: [HACKERS] [OT] MySQL is bad, but THIS bad?

2006-05-18 Thread Florian Weimer
* Mark Woodward: On the other hand, you shouldn't use mysql_use_result() if you are doing a lot of processing for each row on the client side, or if the output is sent to a screen on which the user may type a ^S (stop scroll). This ties up the server and prevent other threads from updating

Re: [HACKERS] PL/pgSQL 'i = i + 1' Syntax

2006-05-18 Thread Florian Weimer
* Jonah H. Harris: On 5/17/06, Hannu Krosing [EMAIL PROTECTED] wrote: Does ADA have both assignment and comparison as operators, or is assignment a statement ? Yes. Assignment is := and comparison is = And its name is spelled Ada, not ADA, even though the language itself is

Re: [HACKERS] PostgreSQL not ACID compliant?

2003-09-20 Thread Florian Weimer
scott.marlowe [EMAIL PROTECTED] writes: Postgresql supports Serializable transactions, which are 100% ACID compliant. How can I activate it? 8-) Yes, I know about SET TRANSACTION ISOLATION LEVEL SERIALIZABLE, please read on. Given the two tables: CREATE TABLE items (item INTEGER); CREATE

Re: [HACKERS] sync_file_range()

2006-06-19 Thread Florian Weimer
* Simon Riggs: Other files are fsynced at checkpoint - always all dirty blocks in the whole file. Optionally, sync_file_range does not block the calling process, so it's very easy to flush all files at once, which could in theory reduce seeking overhead. ---(end of

Re: [HACKERS] vacuum, performance, and MVCC

2006-06-23 Thread Florian Weimer
* Gavin Sherry: Tom Lane's MVCC talk: http://www.postgresql.org/files/developer/transactions.pdf Is this still up-to-date with regard to to partial page writes? I hope that has been fixed (like the fsync issue). ---(end of broadcast)--- TIP 9:

Re: [HACKERS] Block-level CRC checks

2008-10-01 Thread Florian Weimer
it to disk (= torn page). The CRC would not match, even though the page is actually valid. The non-logged hint bit writes are somewhat dangerous anyway. Maybe it's time to get rid of this peculiarity, despite the performance impact? -- Florian Weimer[EMAIL PROTECTED] BFK edv

Re: [HACKERS] Block-level CRC checks

2008-10-01 Thread Florian Weimer
. And for large blocks, Adler32 isn't that bad compared to CRC32 from a error detection POV, so maybe you could use that. I've seen faults which were uncovered by page-level checksumming, so I'd be willing to pay the performance cost. 8-/ -- Florian Weimer[EMAIL PROTECTED] BFK edv

Re: [HACKERS] Block-level CRC checks

2008-10-02 Thread Florian Weimer
). -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your

Re: [HACKERS] Block-level CRC checks

2008-10-31 Thread Florian Weimer
), and I think the text book algorithms don't assume this behavior, either. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 -- Sent via pgsql

Re: [HACKERS] Block-level CRC checks

2009-12-01 Thread Florian Weimer
, since that will happen very quickly anyway. What about putting the whole visibility information out-of-line, into its own B-tree, indexed by page number? -- Florian Weimerfwei...@bfk.de BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201

Re: [HACKERS] YAML Was: CommitFest status/management

2009-12-07 Thread Florian Weimer
instantiations (and it's not possible to switch this off, or it's rather involved to do so). Plain JSON doesn't have this issue. -- Florian Weimerfwei...@bfk.de BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe

Re: [HACKERS] YAML Was: CommitFest status/management

2009-12-07 Thread Florian Weimer
* Alvaro Herrera: Florian Weimer escribió: * Dimitri Fontaine: Well we have JSON and agreed it was a good idea to have it. Now JSON is a subset of YAML and some would prefer another YAML style (me included). YAML is rather difficult to parse, and most parsers assume a trusted document

Re: [HACKERS] Update on true serializable techniques in MVCC

2009-12-16 Thread Florian Weimer
a unique constraint violation caused by a phantom from an application bug. (We currently faking this by retrying a fixed number of times and bailing out if the error returned by PostgreSQL looks like a unique constraint violation.) -- Florian Weimerfwei...@bfk.de BFK edv-consulting GmbH

Re: [HACKERS] Update on true serializable techniques in MVCC

2009-12-18 Thread Florian Weimer
, no? They are detected. In this context, serialization failure means that PostgreSQL generates a history which lacks one-copy serializability, without reporting any errors. (In the general case, the unique constraint violation which bugs me personally is a different beast and does result in an error.) -- Florian

Re: [HACKERS] MySQL-ism help patch for psql

2010-01-21 Thread Florian Weimer
, or \? for general help with psql commands ERROR: unrecognized configuration parameter databases NOTICE: use \l to list databases, or \? for general help with psql commands (I hope that this is less controversial, too.) -- Florian Weimerfwei...@bfk.de BFK edv-consulting GmbH

Re: [HACKERS] Confusion over Python drivers

2010-02-08 Thread Florian Weimer
* Jeff Davis: I have written up a set of guidelines for driver development based on what I learned working on ruby-pg: http://wiki.postgresql.org/wiki/Driver_development Interesting, thanks. I'm contemplating to create a new language binding for libpq (or, to be more precise, turn an

Re: [HACKERS] Confusion over Python drivers

2010-02-08 Thread Florian Weimer
* Andrew McNamara: Any other suggestions before I turn the above into a roadmap page on the wiki? I got sick of the constant stream of escaping bugs impacting on psycopg and pyPgSQL, and wrote my own DB-API driver, using the more modern libpq/binary/protocol 3 APIs where ever possible. The

Re: [HACKERS] Confusion over Python drivers

2010-02-14 Thread Florian Weimer
* Jeff Davis: Agreed. Ultimately, the conversion has to be done somewhere, but I don't believe the driver is the place for it. Type conversions are always going to be imperfect, and this has some important consequences: * The type conversion system will be endlessly tweaked to improve it *

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync

2010-02-14 Thread Florian Weimer
* Tom Lane: Which options would that be? I am not aware that there any for any of the recent linux filesystems. Shouldn't journaling of metadata be sufficient? You also need to enforce ordering between the directory update and the file update. The file metadata is flushed with fsync(), but

Re: [HACKERS] [GENERAL] Undetected corruption of table files

2007-08-29 Thread Florian Weimer
be pretty straightforward). Something like an Adler32 checksum (not a full CRC) on each page might be helpful. However, what I'd really like to see is something that catches missed writes, but this is very difficult to implement AFAICT. -- Florian Weimer[EMAIL PROTECTED] BFK edv

Re: [HACKERS] Something's been bugging me

2007-10-04 Thread Florian Weimer
. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 ---(end of broadcast)--- TIP 4: Have you searched our

Re: [HACKERS] Add YAML option to explain

2009-08-28 Thread Florian Weimer
* Greg Sabino Mullane: I thought the consensus was that we didn't want to get into supporting more formats. What does YAML provide that JSON does not? Readability and easy editing. All the power of JSON without the annoying quotes, braces, and brackets. But YAML is much more difficult to

Re: [HACKERS] Cached Query Plans

2008-04-15 Thread Florian Weimer
in front of it, which breaks with temporary tables). -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 -- Sent via pgsql-hackers mailing list (pgsql

Re: [HACKERS] Protection from SQL injection

2008-05-04 Thread Florian Weimer
* Thomas Mueller: What do you think about it? Do you think it makes sense to implement this security feature in PostgreSQL as well? Can't this be implemented in the client library, or a wrapper around it? A simple approximation would be to raise an error when you encounter a query string that

Re: [HACKERS] Is mdextend really safe?

2008-08-20 Thread Florian Weimer
fragmented files on the file systems I use, and I don't see this with PostgreSQL. (It's one of my gripes with Berkeley DB.) However, I looked at the code recently and couldn't figure out *why* PostgreSQL's observed behavior is this way. 8-( -- Florian Weimer[EMAIL PROTECTED] BFK

Re: [HACKERS] [GENERAL] 8.2.3: Server crashes on Windows using Eclipse/Junit

2007-10-22 Thread Florian Weimer
* Magnus Hagander: Oh, that's interesting. That's actually a sideeffect of us increasing the stack size for the postgres.exe executable in order to work on other things. By default, it burns 1MB/thread, but ours will do 4MB. Never really thought of the problem that it'll run out of address

Re: [HACKERS] Opportunity for a Radical Changes in Database Software

2007-10-27 Thread Florian Weimer
* J. Andrew Rogers: Everything you are looking for is here: http://web.mit.edu/dna/www/vldb07hstore.pdf It is the latest Stonebraker et al on massively distributed in-memory OLTP architectures. Ruby-on-Rails compiles into standard JDBC, but hides all the complexity of that interface.

Re: [HACKERS] BK-Tree Implementation on top of GiST

2007-10-28 Thread Florian Weimer
* Volkan YAZICI: [1] Some approaches to best-match file searching http://portal.acm.org/citation.cfm?id=362003.362025 http://citeseer.ist.psu.edu/1593.html suggests that this uninteresting (too much of the database is examined) once you go past an edit distance of 1. I don't know if this

Re: [HACKERS] Hmmm ... isn't count_nondeletable_pages all wet?

2007-10-29 Thread Florian Weimer
* Tom Lane: I am fairly sure that this bug explains problems previously reported by Merlin Moncure: http://archives.postgresql.org/pgsql-general/2006-10/msg01312.php and Florian Weimer: http://archives.postgresql.org/pgsql-general/2006-11/msg00305.php In both those cases, off-list

Re: [HACKERS] Obfuscated definitions of database objects

2007-10-29 Thread Florian Weimer
* Joshua D. Drake: If you need obfuscation (and you don't, you just think you do, no offense) use C. Or put the relevant code into some package/module/whatever, stored on the file system, and include that. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http

[HACKERS] Asynchronous commit documentation gap

2007-11-02 Thread Florian Weimer
The documentation doesn't really tell how to disable synchronous commits for a single commit. I believe the correct command is SET LOCAL synchronous_commit TO OFF; just before the COMMIT statement. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http

Re: [HACKERS] Ordered Append Node

2007-11-23 Thread Florian Weimer
* Markus Schiltknecht: uses a heap to efficiently find the next value from the source tapes. Well, maybe my point here is: why do you need the heap to sort? I think you need it because there are potentially many input types. -- Florian Weimer[EMAIL PROTECTED] BFK edv

Re: [HACKERS] Ordered Append Node

2007-11-23 Thread Florian Weimer
at your zipper again, it's actually an implementation of a heap. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 ---(end

Re: [HACKERS] Ordered Append Node

2007-11-23 Thread Florian Weimer
* Markus Schiltknecht: Florian Weimer wrote: I think you need it because there are potentially many input types. Eh, tapes. Given the partitioning case, I'd expect all rows to have an equal tuple descriptor. Maybe this is a matter of what to optimize, then? Could you elaborate on what use

Re: [HACKERS] [GENERAL] SHA1 on postgres 8.3

2008-01-20 Thread Florian Weimer
additional security. (Sorry if this is what you've said.) -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 ---(end

Re: [HACKERS] [GENERAL] SHA1 on postgres 8.3

2008-01-21 Thread Florian Weimer
matter for many application). It's a bit like justifying that you don't need a virus scanner on your non-Windows server or database server. 8-P BTW, I'd like to see MD5/SHA-1 for BYTEA, not just TEXT, and with a BYTEA return value. Does pgcrypto provide that? -- Florian Weimer

[HACKERS] plperl: Documentation on BYTEA decoding is wrong

2008-01-25 Thread Florian Weimer
because pre-escaped backslashes like like '\\101' cause problems otherwise. (All ''-delimited strings in this posting use strict SQL syntax, i.e. no escaped backslashes.) -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100

Re: [HACKERS] plperl: Documentation on BYTEA decoding is wrong

2008-01-28 Thread Florian Weimer
* Robert Treat: Note we've been using Theo's plperl bytea patch on one of our production servers for some time; if anyone wants access to that lmk. I'm interested. Could you post a pointer to this code, please? -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH

Re: [HACKERS] [GENERAL] SHA1 on postgres 8.3

2008-01-29 Thread Florian Weimer
function in pgcrypto should be used instead? Yes, that would probably help those folks doing checklist-based security audits. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe

Re: [HACKERS] configurability of OOM killer

2008-02-02 Thread Florian Weimer
if the sysadmin hasn't configured it. How much does that help? Postmaster c still need to be shut down when a regular backend dies due to SIGKILL. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D

Re: [HACKERS] configurability of OOM killer

2008-02-02 Thread Florian Weimer
thanks to COW), and the child runs into the same OOM condition. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99

Re: [HACKERS] configurability of OOM killer

2008-02-02 Thread Florian Weimer
with this mode (SBCL, for instance, and the Sun JVM doesn't perform as well as it could, either), but there are astonishingly few problems with vm.overcommit_memory=2. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49

Re: [HACKERS] Read-ahead and parallelism in redo recovery

2008-02-29 Thread Florian Weimer
does not result in lots of random I/O (with 8.3 and full page writes active; this is a relatively recent change). In the end, I wouldn't be surprised if for most loads, cache warming effects dominated recovery times, at least when the machine is not starved on RAM. -- Florian Weimer

Re: [HACKERS] [BUGS] Invalid YAML output from EXPLAIN

2010-06-07 Thread Florian Weimer
before that YAML is a superset of JSON, so why can't the YAML folks use the existing JSON output instead? -- Florian Weimerfwei...@bfk.de BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721

Re: [HACKERS] [BUGS] Invalid YAML output from EXPLAIN

2010-06-08 Thread Florian Weimer
* Greg Smith: Florian Weimer wrote: It has been claimed before that YAML is a superset of JSON, so why can't the YAML folks use the existing JSON output instead? Because JSON just crosses the line where it feels like there's so much markup that people expect a tool is necessary to read

Re: [HACKERS] antisocial things you can do in git (but not CVS)

2010-07-23 Thread Florian Weimer
accidentally push a merge commit, either because they forgot to squash locally, or because of a conflict between their local git repo's master branch and origin/master. Can we forbid this? It's possible to do this with some scripting on the server side. -- Florian Weimerfwei...@bfk.de

Re: [HACKERS] UTF16 surrogate pairs in UTF8 encoding

2010-08-23 Thread Florian Weimer
, I really question the sense of this. Usually, people want CESU-8 to preserve ordering between languages such as C# and Java and their database, and conversion destroys this property. -- Florian Weimerfwei...@bfk.de BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße

Re: [HACKERS] renaming storage parameters

2009-02-09 Thread Florian Weimer
* Alvaro Herrera: Euler Taveira is arguing in an autovacuum thread that we should give storage parameters a different name; his argument is that autovacuum_enabled is not really a parameter that relates to storage. He is proposing relation parameters. They also apply to indices, right? I

Re: [HACKERS] Index Tuning Features

2006-10-12 Thread Florian Weimer
hard to gather from a sample, e.g. the number of distinct values in a column. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Durlacher Allee 47tel: +49-721-96201-1 D-76131 Karlsruhe fax: +49-721-96201-99

Re: [HACKERS] Asynchronous I/O Support

2006-10-17 Thread Florian Weimer
* Neil Conway: [1] http://lse.sourceforge.net/io/aio.html Last Modified Mon, 07 Jun 2004 12:00:09 GMT But you are right -- it seems that io_submit still blocks without O_DIRECT. *sigh* -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de

Re: [HACKERS] [PERFORM] EXPLAIN ANALYZE on 8.2

2006-12-15 Thread Florian Weimer
) are acceptable, you should assume that the problem will eventually fix itself. FWIW, I see the 9x overhead on something that is close to 2.6.17 (on AMD64/Opteron), so this could be wishful thinking. 8-( -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de

Re: [HACKERS] TODO: GNU TLS

2007-01-03 Thread Florian Weimer
* Stephen Frost: Ah, this does sound rather ugly and not something we'd want. The particular library doesn't make a whole heck of alot of difference to me provided it has the general functionality necessary and a compatible license (where 'compatible' in this case really means 'Debian feels

Re: [HACKERS] [PATCHES] wal_checksum = on (default) | off

2007-01-04 Thread Florian Weimer
* Simon Riggs: Surely not. Otherwise even the on setting is not really a defense. Only when the CRC is exactly zero, which happens very very rarely. Have you tried switching to Adler32 instead of CRC32? -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http

Re: [HACKERS] [PATCHES] wal_checksum = on (default) | off

2007-01-04 Thread Florian Weimer
* Tom Lane: Florian Weimer [EMAIL PROTECTED] writes: Have you tried switching to Adler32 instead of CRC32? Is anything known about the error detection capabilities of Adler32? There's a lot of math behind CRCs but AFAIR Adler's method is pretty much ad-hoc. Correct me if I'm wrong

Re: [HACKERS] [PATCHES] wal_checksum = on (default) | off

2007-01-04 Thread Florian Weimer
* Tom Lane: I think short burst errors are fairly likely: the kind of scenario I'm worried about is a wild store corrupting a word of a WAL entry while it's waiting around to be written in the WAL buffers. Ah, does this mean that each WAL entry gets its own checksum? In this case, Adler32 is

Re: [HACKERS] SCMS question

2007-02-23 Thread Florian Weimer
* Bruce Momjian: The fact that you're still thinking in patch application means you're still stuck in the CVS worldview. To apply a patch in a distributed SCM(*) really means to merge a branch into the main development branch. Of course, you can still see the entire diff -c if you want.

Re: [HACKERS] Bug: Buffer cache is not scan resistant

2007-03-05 Thread Florian Weimer
. Uhm, if it's not in the cache, you typically need to evict some cache lines to make room for the data, so I'd expect an indirect performance hit. I could be mistaken, though. -- Florian Weimer[EMAIL PROTECTED] BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100

Re: [HACKERS] Copyrights on files

2007-03-26 Thread Florian Weimer
* Bruce Momjian: src/backend/port/dynloader/aix.c * This is an unpublished work copyright (c) 1992 HELIOS Software GmbH * 30159 Hannover, Germany The company still exists, it seems. Have you tried to contact them? See http://www.helios.de/about/email.phtml. -- Florian

Re: [HACKERS] [PATCH v2] Add bit operations util header

2009-06-03 Thread Florian Weimer
* Jeremy Kerr: +#if defined(__GNUC__) \ + (defined(__ppc__) || defined(__powerpc__) || \ + defined(__ppc64__) || defined (__powerpc64__)) If you require GCC anyway, you can use __builtin_clz instead. (It's been available since GCC 4.1 at least.) -- Florian Weimer

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