AW: BLERe: AW: AW: [HACKERS] relation ### modified while in use
Are there many applications which have many SELECT statements(without FOR UPDATE) in one tx ? Why not ? It seems to me that multiple SELECT statements in a tx has little meaning unless the tx is executed in SERIALIZABLE isolation level. E.g. a table is accessed multiple times to select different data in an inner application loop. No need for serializable here. Andreas
Re: AW: BLERe: AW: AW: [HACKERS] relation ### modified while in use
Zeugswetter Andreas SB wrote: Are there many applications which have many SELECT statements(without FOR UPDATE) in one tx ? Why not ? It seems to me that multiple SELECT statements in a tx has little meaning unless the tx is executed in SERIALIZABLE isolation level. E.g. a table is accessed multiple times to select different data in an inner application loop. No need for serializable here. And seems no need to execute in one tx. Hmm,we seems to be able to call a cleanup procedure internally which is equivalent to 'commit' after each consecutive read-only statement. Is it a problem ? Regards. Hiroshi Inoue
Re: AW: AW: BLERe: AW: AW: [HACKERS] relation ### modified while in use
Zeugswetter Andreas SB wrote: [snip] Also the result would be, that the first readonly statements are allowed to see schema changes, but selects after the first DML would not :-( Does it mean that even read-only statements aren't allowed to release locks after other DMLs ? Regards. Hiroshi Inoue
[HACKERS] Two-phase commit
Hello, anyone thought about implementing two-phase commit to be able to support distributed transactions ? I have no clue how complex it would be, someone knows ? devik
[HACKERS] Re: how to access backend pid from libpq ?
Hannu Krosing wrote: I was unable to find the way to access the backend pid from libpq It is probably saved somewhere as part of BackendKeyData message but there seems to be no function to access it ? I'm using a temporary solution (my own 'C' function) but I'd like to use the info already received. Ok, I found it from the libpq source: PQbackendPID I still think it could be documented ;) Hannu
[HACKERS] Re: [COMMITTERS] pgsql/src/backend/access/transam (xact.c xlog.cxlogutils.c)
Vadim B. Mikheev - CVS writes: Date: Tuesday, October 24, 2000 @ 05:56:09 Author: vadim Update of /home/projects/pgsql/cvsroot/pgsql/src/backend/access/transam from hub.org:/home/projects/pgsql/tmp/cvs-serv70071/backend/access/transam Modified Files: xact.c xlog.c xlogutils.c - Log Message - WAL misc We seem to be missing a file "src/include/access/xlogutils.h". -- Peter Eisentraut [EMAIL PROTECTED] http://yi.org/peter-e/
[HACKERS] RE: [INTERFACES] RE: JDBC now needs updates for large objects
Yes, the joins were one of the reasons I was going to do it. If no one starts a list by Saturday, then I'll start one when I go through JDBC. Peter -- Peter Mount Enterprise Support Officer, Maidstone Borough Council Email: [EMAIL PROTECTED] WWW: http://www.maidstone.gov.uk All views expressed within this email are not the views of Maidstone Borough Council -Original Message- From: Tom Lane [mailto:[EMAIL PROTECTED]] Sent: Tuesday, October 24, 2000 1:44 PM To: Peter Mount Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: Re: [INTERFACES] RE: JDBC now needs updates for large objects Peter Mount [EMAIL PROTECTED] writes: Idea: As we have this type of query in more than one part of the source tree (ie: psql, jdbc, probably odbc), should we have a section in the documentation containing common queries, like: retrieving a list of tables, views etc? That's a good thought. It'd be a useful practice to review such standard queries from time to time anyway. For example, now that outer joins work, a lot of psql's backslash-command queries could be simplified (don't need the UNION ALL WITH SELECT NULL hack). Anyone have time to work up a list? regards, tom lane
Re: [HACKERS] relation ### modified while in use
In my understanding,locking levels you provided contains an implicit share/exclusive lock on the corrsponding pg_class tuple i.e. AccessExclusive Lock acquires an exclusive lock on the corresping pg_class tuple and other locks acquire a share lock, Is it right ? No. Access...Locks are acquired over target table (table' oid is used as key for lmgr hash table), not over corresponding pg_class tuple, in what case we would use pg_clas' oid + table' oid as key (possibility I've described below). Yes,I know that "lock table" doesn't touch the correpon ding pg_class tuple at all. However isn't it equivalent ? From what POV? Lock manager will allow two simultaneous exclusive locks using these different methods (keys) and so we can interpret (use) them differently. Vadim
[HACKERS] Fallback behavior for UNKNOWN types -- proposed change
The parser has some heuristics to try to match up existing functions and operators when not all types are known apriori. We've had this capability since v6.4, with some modest evolution since then. Currently, if there is more than one function, say, which *could* match the specified query, and if the arguments with unspecified types (typically looking like a bare SQL9x string) come from different "categories" of types (e.g. integer and string, or float and date) then the parser throws an error about not finding the function. I propose that we modify the heuristic slightly, so that if there are function matches with arguments from different categories, and if one or more of the possible matches comes from the "string" category, then that category is preferred. There are two good reasons for this, and one bad reason ;) : 1) the original query carries "string" semantics, so it is a reasonable fallback interpretation for the query. 2) a string fallback will make things like select tstampfield at time zone 'pst' from t1; and select tstampfield at time zone interval '-08:00' from t1; possible (oh, btw, I've got patches to implement "at time zone..."), where currently select tstampfield at time zone 'pst' from t1; fails and requires that 'pst' be specified as "text 'pst'". 3) some braindead "compatibility tests" from some competing open-source database projects have poorly designed queries which interpret this lack of fallback as a lack of support for database features. So instead of getting extra points for having *more* capabilities in a particular area, they claim that we don't support anything in that area. Most annoying, and it is not likely to change. Comments? I've got code which implements the fallback for functions, and presumably the same for operators will be easy to do... - Thomas
Re: [HACKERS] Two-phase commit
i'm developing one. a library for batch transactions, so you can continue processing in the middle of the file(or table) in case an abort happens. it can support multi-databases. i think i can share it to freshmeat. On Tue, 24 Oct 2000 13:52:38 +0200, [EMAIL PROTECTED] wrote: Hello, anyone thought about implementing two-phase commit to be able to support distributed transactions ? I have no clue how complex it would be, someone knows ? devik ___ Say Bye to Slow Internet! http://www.home.com/xinbox/signup.html
[HACKERS] Re: [PATCHES] add darwin/osxpb support to cvs
Bruce Hartzler writes: this patch and tar archive will add support for the darwin/osxpb to the current cvs tree. Next time you can make your patch with "diff -crN" so that you don't have to create a separate tarball. - the config.guess and config.sub files have been updated by apple to support their new os. i don't think these changes have been folded back in to the main archive yet I installed the latest ones from GNU which claim to support it according to the ChangeLog. - the situation with darwin's implementation of sysv semaphores is in progress at the moment (the shm/ipc support *is* there and seems to work fine). so this patch uses HAVE_SYS_SEM_H to conditionally build HAVE_SYS_SEM_H is a preprocessor symbol, not a makefile variable. the src/backend/port/darwin semaphore code (borrowed from qnx4). If you could arrange it, could you use the same files as QNX, perhaps with an #ifdef here or there I've followed the BeOS example of including the necessary sem.h declarations in src/include/port/darwin.h. this is rather messy at the moment and can be dumped once apple releases a version of PB with sysv sem built into the kernel. The include/port/beos.h isn't really a shining example of how to do this. This file is include *everywhere*, but we don't want to know about semaphores everywhere. I'd prefer it if you use the QNX approach and symlink sem.h into an include directory (e.g., /usr/local/include/sys), since it's only temporary anyway. Also, overriding configure results (à la #undef HAVE_UNION_SEMUN) isn't cool. I'm also somewhat concerned about the dynloader.c because it's under the Apache license which has a funny advertisement clause. Comments from someone? - i'm a bit confused over the __powerpc__ tas function in s_lock.c (there i assume for the ppc-linux port). it doesn't compile at all on darwin so i just added a version that does work on darwin under DARWIN_OS. it's potentially a bit confusing and s_lock.c should probably be changed to include a better conditional. The compiler probably predefines something like __darwin__, which you should use. You can find out with touch foo.h cc -E -dM foo.h rm foo.h And finally, what's up with this: CFLAGS='-O0 -g -traditional-cpp' ? What's wrong with the "modern-cpp"? -- Peter Eisentraut [EMAIL PROTECTED] http://yi.org/peter-e/
Re: [HACKERS] Re: Add support for xti.h
This is an IRIX bug but I think that we need to work around it. Roger, will do. I have changed configure in the CVS repository to test for netinet/tcp.h per your recommendation. At your convenience, please verify that it really does do the right thing on IRIX. regards, tom lane
Re: [HACKERS] Re: Add support for xti.h
Pete Forman [EMAIL PROTECTED] writes: On IRIX 6.5.5m I get the following error. The header standards.h is included by (nearly!) all of the standard headers. It is the IRIX equivalent of config.h if you will. configure:4349: checking for netinet/tcp.h configure:4359: cc -E conftest.c /dev/null 2conftest.out cc-1035 cc: WARNING File = /usr/include/sys/endian.h, Line = 32 #error directive: "standards.h must be included before sys/endian.h." #error "standards.h must be included before sys/endian.h." ^ configure: failed program was: #line 4354 "configure" #include "confdefs.h" #include netinet/tcp.h How bizarre. One would think it'd make more sense to just include the desired file, instead of going belly-up like that. In order to preprocess this test on IRIX a system header such as stdio.h must precede netinet/tcp.h. The logical choice of header to use is netinet/in.h as tcp.h is supplying values for levels defined in in.h. This is an IRIX bug but I think that we need to work around it. Roger, will do. regards, tom lane
Re: [HACKERS] Re: Add support for xti.h
Tom Lane writes: Actually, given your description of the problem, I'm half inclined to revert the whole patch and instead make configure's test for availability of netinet/tcp.h first include netinet/in.h, so that that configure test will succeed on IRIX etc. Pete, After looking at this I'm confused again. The configure test consists of seeing whether cpp will process #include netinet/tcp.h without complaint. I can well believe that the full C compilation process will generate errors if netinet/tcp.h is included without also including netinet/in.h, but it's a little harder to believe that cpp alone will complain. Could you double-check this? It would be useful to look at the config.log file generated by the configure run that's reporting tcp.h isn't found. It should contain the error messages generated by failed tests. On IRIX 6.5.5m I get the following error. The header standards.h is included by (nearly!) all of the standard headers. It is the IRIX equivalent of config.h if you will. In order to preprocess this test on IRIX a system header such as stdio.h must precede netinet/tcp.h. The logical choice of header to use is netinet/in.h as tcp.h is supplying values for levels defined in in.h. This is an IRIX bug but I think that we need to work around it. configure:4349: checking for netinet/tcp.h configure:4359: cc -E conftest.c /dev/null 2conftest.out cc-1035 cc: WARNING File = /usr/include/sys/endian.h, Line = 32 #error directive: "standards.h must be included before sys/endian.h." #error "standards.h must be included before sys/endian.h." ^ configure: failed program was: #line 4354 "configure" #include "confdefs.h" #include netinet/tcp.h -- Pete Forman -./\.- Disclaimer: This post is originated Western Geophysical -./\.- by myself and does not represent [EMAIL PROTECTED] -./\.- the opinion of Baker Hughes or http://www.crosswinds.net/~petef -./\.- its divisions.
Re: [HACKERS] Mailing list archives available?
On Tue, 24 Oct 2000, Vince Vielhaber wrote:
On Tue, 24 Oct 2000, The Hermit Hacker wrote:
http://www.postgresql.org/mhonarc has them all listed .. not sure how to
get there from the Web site ... Vince?
There are links from both the Developer's Corner and User's Lounge -
General Info.
Ya know, I've gone in and looked several times and my eye always gets draw
down to the section titled ' Mailing Lists '? :) Can you put lnks from
the 'pgsql-{admin,announce,general,etc}' in that section to the archives
as well, so its a bit easier to find? And maybe 'bold' the words "mailing
lists" in the General Info section, so that it stands out a bit more? :)
Vince.
On Mon, 23 Oct 2000, Krzysztof Kowalczyk wrote:
Are mailing list archives of various postgresql mailing list available
anywhere?
I know they were some time ago but I couldn't find any link on
www.postgresql.org now. I subscribed to a list mainly because I want to
monitor the progress but the amount of messages kills my inbox. It would
be really convenient for me if I could just browse the archives on web
once in a while.
Krzysztof Kowalczyk
Marc G. Fournier ICQ#7615664 IRC Nick: Scrappy
Systems Administrator @ hub.org
primary: [EMAIL PROTECTED] secondary: scrappy@{freebsd|postgresql}.org
--
==
Vince Vielhaber -- KA8CSHemail: [EMAIL PROTECTED]http://www.pop4.net
128K ISDN from $22.00/mo - 56K Dialup from $16.00/mo at Pop4 Networking
Online Campground Directoryhttp://www.camping-usa.com
Online Giftshop Superstorehttp://www.cloudninegifts.com
==
Marc G. Fournier ICQ#7615664 IRC Nick: Scrappy
Systems Administrator @ hub.org
primary: [EMAIL PROTECTED] secondary: scrappy@{freebsd|postgresql}.org
[HACKERS] Re: [PATCHES] binary operators on integers
Peter Eisentraut [EMAIL PROTECTED] writes: This patch was installed, with xor as "#". The parser still needs work. Besides the known issue of "|", this also parses funny: = select 5 ~ 6; ERROR: Unable to identify a right operator '' for type 'int4' I think we're kind of stuck on that, at least in terms of a solution specifically for ~ --- I don't think we should be wiring knowledge of whether specific operators are prefix/suffix/infix into the grammar. It might perhaps be possible to tweak the grammar so that operand operator operator operand is generically resolved as operand infix-op (prefix-op operand) and not (operand postfix-op) infix-op operand the way it is now. Given that postfix operators are relatively seldom used, this seems a more sensible default --- but I suppose somewhere out there is an application that will break. (At least it probably won't break silently.) Comments anyone? regards, tom lane
[HACKERS] Bogus-looking SSL code in postmaster wait loop
The postmaster contains this code just before it waits for input:
#ifdef USE_SSL
for (curr = DLGetHead(PortList); curr; curr = DLGetSucc(curr))
{
if (((Port *) DLE_VAL(curr))-ssl
SSL_pending(((Port *) DLE_VAL(curr))-ssl) 0)
{
no_select = true;
break;
}
}
if (no_select)
FD_ZERO(rmask);/* So we don't accept() anything below */
#endif
I am not sure exactly what SSL_pending() is defined to mean, but as
near as I can tell, whenever SSL_pending() returns true, the postmaster
will completely ignore every other input-ready condition. This spells
"denial of service" from where I sit: a nonresponsive SSL client will
cause the postmaster to freeze up for all other clients.
Can anyone who knows about SSL defend or even explain the above code?
I am strongly inclined to just dike it out.
regards, tom lane
[HACKERS] Re: [PATCHES] add darwin/osxpb support to cvs
Next time you can make your patch with "diff -crN" so that you don't have to create a separate tarball. No problem. I tried just doing a diff with cvs but wasn't able to get the -N option to work. This is the first time I've ever tried patching unix software so I'm sorry if it's a bit messy. Thanks for you help in getting it right. - the config.guess and config.sub files have been updated by apple to support their new os. i don't think these changes have been folded back in to the main archive yet I installed the latest ones from GNU which claim to support it according to the ChangeLog. I'll try checking out the new versions and see if they work. I can send you a diff with the ones I have here if you want to see the additions Apple made. I've followed the BeOS example of including the necessary sem.h declarations in src/include/port/darwin.h. this is rather messy at the moment and can be dumped once apple releases a version of PB with sysv sem built into the kernel. The include/port/beos.h isn't really a shining example of how to do this. This file is include *everywhere*, but we don't want to know about semaphores everywhere. I'd prefer it if you use the QNX approach and symlink sem.h into an include directory (e.g., /usr/local/include/sys), since it's only temporary anyway. I agree it's rather messy. I originally had just used the sym link in /usr/local/include, but as I said, some of the newer Darwin kernels have the sysv sem.h file already there and I was worried about people overwriting it. If you think it's fair to put this responsibility on the end user, I'm ok with that. I just thought it might be nice to check and see if the semaphore implementation was already there, and if not, build the necessary parts. I'll switch it back to the way it was. I'm also somewhat concerned about the dynloader.c because it's under the Apache license which has a funny advertisement clause. Comments from someone? I wondering about this too. I'll try emailing Wilfredo Sanchez and see if I can get the code outside the Apache license. This would probably be easiest. The compiler probably predefines something like __darwin__, which you should use. You can find out with It doesn't actually provide __darwin__ but as I mentioned in a previous post, Apple is suggesting people use __APPLE__ combined with __ppc__ or __i386__ for the different darwin builds. The section in s_lock.c should probably be changed to reflect this instead of using DARWIN_OS. And finally, what's up with this: CFLAGS='-O0 -g -traditional-cpp' ? What's wrong with the "modern-cpp"? Apple's "modern-cpp" called cpp-precomp uses some strange parsing that breaks on several files in the postgresql build. They are still working on it apparently and are suggesting people simply use the -traditional-cpp flag when this happens instead of trying to update the files. Thanks again for all your comments and suggestions. Bruce
