Re: [HACKERS] SQL99 hierarchical queries stalled
On Tue, May 17, 2005 at 11:24:19PM +0300, Hannu Krosing wrote: > On T, 2005-05-17 at 11:22 -0400, Tom Lane wrote: > > Hannu Krosing <[EMAIL PROTECTED]> writes: > > > On T, 2005-05-17 at 00:42 -0400, Tom Lane wrote: > > >> I seem to recall some discussion of how to do this in the past; > > >> have you trolled the pghackers archives? > > > > > I think that Jasons inspiration for doing it came from the the fact that > > > there are already now abandoned patches for doing it. > > > > Having looked over the latest patch, my advice would be to ignore it :-( > > It's almost completely devoid of documentation, except for comments > > that he copied-and-pasted from elsewhere without modification. Wrong > > comments are even worse than none. > > ANd even worse - this is from the README on the website: > > 8<-8<-8<-8<-8<-8<-8<- > WHAT'S THIS > > This is a patch which allows PgSQL to make hierarchical queries a la > Oracle do. > > (c) Evgen Potemkin 2003,2004, < gppl at inbox dot ru >, entirely based > on PostgreSQL (http://www.postgresql.org) > Patch itself distributed under GPL. No warranty of any kind is given, > use it at your own risk. It's the notes on the CONNECT BY patch, not the WITH patch. The WITH patch, as far as I can tell, is in the public domain. Cheers, D -- David Fetter [EMAIL PROTECTED] http://fetter.org/ phone: +1 510 893 6100 mobile: +1 415 235 3778 Remember to vote! ---(end of broadcast)--- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [HACKERS] SQL99 hierarchical queries stalled
On T, 2005-05-17 at 11:22 -0400, Tom Lane wrote: > Hannu Krosing <[EMAIL PROTECTED]> writes: > > On T, 2005-05-17 at 00:42 -0400, Tom Lane wrote: > >> I seem to recall some discussion of how to do this in the past; > >> have you trolled the pghackers archives? > > > I think that Jasons inspiration for doing it came from the the fact that > > there are already now abandoned patches for doing it. > > Having looked over the latest patch, my advice would be to ignore it :-( > It's almost completely devoid of documentation, except for comments > that he copied-and-pasted from elsewhere without modification. Wrong > comments are even worse than none. ANd even worse - this is from the README on the website: 8<-8<-8<-8<-8<-8<-8<- WHAT'S THIS This is a patch which allows PgSQL to make hierarchical queries a la Oracle do. (c) Evgen Potemkin 2003,2004, < gppl at inbox dot ru >, entirely based on PostgreSQL (http://www.postgresql.org) Patch itself distributed under GPL. No warranty of any kind is given, use it at your own risk. 8<-8<-8<-8<-8<-8<-8<- So the license is also incompatible :( -- Hannu Krosing <[EMAIL PROTECTED]> ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [HACKERS] SQL99 hierarchical queries stalled
Tom Lane wrote: > Hannu Krosing <[EMAIL PROTECTED]> writes: > > On T, 2005-05-17 at 00:42 -0400, Tom Lane wrote: > >> I seem to recall some discussion of how to do this in the past; > >> have you trolled the pghackers archives? > > > I think that Jasons inspiration for doing it came from the the fact that > > there are already now abandoned patches for doing it. > > Having looked over the latest patch, my advice would be to ignore it :-( > It's almost completely devoid of documentation, except for comments > that he copied-and-pasted from elsewhere without modification. Wrong > comments are even worse than none. > > What I'd like to see before anyone writes a line of code is a text > document explaining how this is going to work: what's the plan tree > structure, what happens at execution time, how much of the SQL99 spec > is going to get implemented. If you don't have that understanding > first, you're going to get buried in irrelevant details. I have updated the developer's FAQ to cover these suggestions on how to start a patch: 1.4) What do I do after choosing an item to work on? Send an email to pgsql-hackers with a proposal for what you want to do (assuming your contribution is not trivial). Working in isolation is not advisable because others might be working on the same TODO item, or you might have misunderstood the TODO item. In the email, discuss both the internal implementation method you plan to use, and any user-visible changes (new syntax, etc). For complex patches, it is important to get community feeback on your proposal before starting work. Failure to do so might mean your patch is rejected. -- Bruce Momjian| http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup.| Newtown Square, Pennsylvania 19073 ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] SQL99 hierarchical queries stalled
Hannu Krosing <[EMAIL PROTECTED]> writes: > On T, 2005-05-17 at 00:42 -0400, Tom Lane wrote: >> I seem to recall some discussion of how to do this in the past; >> have you trolled the pghackers archives? > I think that Jasons inspiration for doing it came from the the fact that > there are already now abandoned patches for doing it. Having looked over the latest patch, my advice would be to ignore it :-( It's almost completely devoid of documentation, except for comments that he copied-and-pasted from elsewhere without modification. Wrong comments are even worse than none. What I'd like to see before anyone writes a line of code is a text document explaining how this is going to work: what's the plan tree structure, what happens at execution time, how much of the SQL99 spec is going to get implemented. If you don't have that understanding first, you're going to get buried in irrelevant details. regards, tom lane ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
[HACKERS] SQL99 hierarchical queries stalled
David-- My boss has given me approval to put up to 8 hours per week of SourceLabs' time in on the SQL99 hierarchical query implementation. (I'm free, of course, to supplement this with whatever of my own time I can spare.) I'm willing to take on the work. What's the next step? --Jason ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
Re: [HACKERS] SQL99 hierarchical queries stalled
On T, 2005-05-17 at 00:42 -0400, Tom Lane wrote: > David Fetter <[EMAIL PROTECTED]> writes: > >> What's the next step? > > > I suppose the first thing would be to look over the patches I > > mentioned and the SQL:2003 specification, then put together a > > preliminary patch and send it to -hackers. ... > I seem to recall some discussion of how to do this in the past; > have you trolled the pghackers archives? I think that Jasons inspiration for doing it came from the the fact that there are already now abandoned patches for doing it. So studying/understanding the current patch, and describing and getting feedback from pgsql-hackers should be quite a good way of gaining insight in trickier parts of postgres. So it will not be jumping at new problem and writing a patch, but rather trying to get an existing patch into good shape for being accepted in the backend. -- Hannu Krosing <[EMAIL PROTECTED]> ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] SQL99 hierarchical queries stalled
David Fetter <[EMAIL PROTECTED]> writes: >> What's the next step? > I suppose the first thing would be to look over the patches I > mentioned and the SQL:2003 specification, then put together a > preliminary patch and send it to -hackers. You can get useful feedback long before having anything that looks like a patch --- and I'd encourage you to do so. Send us design notes, rough data structures, etc. Quite honestly, hierarchical queries aren't the easiest thing in the world and wouldn't be my recommendation of the first ... or even the second ... backend hacking project for a new posthacker to tackle. If that's where you feel you must start, OK, but try to get as much feedback as soon as you can, sooner not later. I seem to recall some discussion of how to do this in the past; have you trolled the pghackers archives? regards, tom lane ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] SQL99 hierarchical queries stalled
On Mon, May 16, 2005 at 03:09:18PM -0700, [EMAIL PROTECTED] wrote: > David-- > > My boss has given me approval to put up to 8 hours per week of > SourceLabs' time in on the SQL99 hierarchical query implementation. That's great! :) > (I'm free, of course, to supplement this with whatever of my own > time I can spare.) I'm willing to take on the work. What's the > next step? I suppose the first thing would be to look over the patches I mentioned and the SQL:2003 specification, then put together a preliminary patch and send it to -hackers. Cheers, David. -- David Fetter [EMAIL PROTECTED] http://fetter.org/ phone: +1 510 893 6100 mobile: +1 415 235 3778 Remember to vote! ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
Re: [Fwd: Re: [HACKERS] SQL99 Hierarchical queries]
On Sun, May 15, 2005 at 04:44:57PM +0800, Christopher Kings-Lynne wrote: > Looks like hierarchical queries are now officially stalled :( > > Anyone want to take this up for 8.1? Sergei and Jason, Feel like taking SQL:1999 WITH RECURSIVE? It would be a giant help to the PostgreSQL community. :) http://gppl.moonbone.ru/index.shtml has part of it, and http://candle.pha.pa.us/mhonarc/patches2/msg00175.html has others. There's also MERGE, which is covered starting on page 47 of http://wiscorp.com/sql/SQL2003Features.pdf also pp 839-845 of 5WD-02-Foundation-2003-09.pdf which is part of this: http://wiscorp.com/sql/sql_2003_standard.zip and an overview here: http://www.varlena.com/varlena/GeneralBits/73.php Cheers, D > Hi, > > I haven't done any significant progress on that way because of lack of > free time. > Beside this, I'm recently changed my job and now I'm woking for MySQL. > I think it's not possible for me to continue work on PostgreSQL. > Feel free to take the patch and develop it further as long as you > mention me as author of initial version. > > Regards, Evgen. > > On 5/5/05, Christopher Kings-Lynne <[EMAIL PROTECTED]> wrote: > >Hi Evgen, > > > >I just keep pinging this patch thread every once in a while to make sure > >it doesn't get forgotten :) > > > >How is the syncing with 8.1 CVS coming along? > > > >Chris > > > >Evgen Potemkin wrote: > >> Hi hackers! > >> > >> I have done initial implementation of SQL99 WITH clause (attached). > >> It's now only for v7.3.4 and haven't a lot of checks and restrictions. > >> It can execute only simple WITH queries like > >> WITH tree AS (SELECT id,pnt,name,1::int AS level FROM t WHERE id=0 > >> UNION SELECT t.id,t.pnt,t.name,tree.level+1 FROM t JOIN tree ON > >> tree.id=t.pnt ) SELECT * FROM tree; > >> It would be great if someone with knowledge of Pg internals can make a > >> kind of code review and make some advices how to better implement all > >> this. > >> > >> Regards, Evgen. > >> > >> > >> > >> > >> > >> ---(end of broadcast)--- > >> TIP 3: if posting/reading through Usenet, please send an appropriate > >> subscribe-nomail command to [EMAIL PROTECTED] so that your > >> message can get through to the mailing list cleanly > > > > ---(end of broadcast)--- > TIP 7: don't forget to increase your free space map settings On Wed, May 11, 2005 at 07:01:50PM -0700, Sergey Ten wrote: > Hello all, > > We would like to contribute to the Postgresql community by implementing > the following items from the TODO list > (http://developer.postgresql.org/todo.php): > . Allow COPY to understand \x as a hex byte . Allow COPY to optionally > include column headings in the first line . Add XML output to COPY > > The changes are straightforward and include implementation of the > features as well as modification of the regression tests and documentation. > > Before sending a diff file with the changes, we would like to know if > these features have been already implemented. > > Best regards, > Jason Lucas and Sergey Ten > SourceLabs > > Dependable Open Source Systems > > > ---(end of broadcast)--- > TIP 2: you can get off all lists at once with the unregister command >(send "unregister YourEmailAddressHere" to [EMAIL PROTECTED]) -- David Fetter [EMAIL PROTECTED] http://fetter.org/ phone: +1 510 893 6100 mobile: +1 415 235 3778 Remember to vote! ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
[Fwd: Re: [HACKERS] SQL99 Hierarchical queries]
Looks like hierarchical queries are now officially stalled :( Anyone want to take this up for 8.1? Chris Original Message Subject: Re: [HACKERS] SQL99 Hierarchical queries Date: Sun, 15 May 2005 07:31:16 +0400 From: Evgen Potemkin <[EMAIL PROTECTED]> Reply-To: Evgen Potemkin <[EMAIL PROTECTED]> To: Christopher Kings-Lynne <[EMAIL PROTECTED]> References: <[EMAIL PROTECTED]> <[EMAIL PROTECTED]> Hi, I haven't done any significant progress on that way because of lack of free time. Beside this, I'm recently changed my job and now I'm woking for MySQL. I think it's not possible for me to continue work on PostgreSQL. Feel free to take the patch and develop it further as long as you mention me as author of initial version. Regards, Evgen. On 5/5/05, Christopher Kings-Lynne <[EMAIL PROTECTED]> wrote: Hi Evgen, I just keep pinging this patch thread every once in a while to make sure it doesn't get forgotten :) How is the syncing with 8.1 CVS coming along? Chris Evgen Potemkin wrote: > Hi hackers! > > I have done initial implementation of SQL99 WITH clause (attached). > It's now only for v7.3.4 and haven't a lot of checks and restrictions. > It can execute only simple WITH queries like > WITH tree AS (SELECT id,pnt,name,1::int AS level FROM t WHERE id=0 > UNION SELECT t.id,t.pnt,t.name,tree.level+1 FROM t JOIN tree ON > tree.id=t.pnt ) SELECT * FROM tree; > It would be great if someone with knowledge of Pg internals can make a > kind of code review and make some advices how to better implement all > this. > > Regards, Evgen. > > > > > > ---(end of broadcast)--- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to [EMAIL PROTECTED] so that your > message can get through to the mailing list cleanly ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
Re: [HACKERS] SQL99 Hierarchical queries
Hi Evgen, I just keep pinging this patch thread every once in a while to make sure it doesn't get forgotten :) How is the syncing with 8.1 CVS coming along? Chris Evgen Potemkin wrote: Hi hackers! I have done initial implementation of SQL99 WITH clause (attached). It's now only for v7.3.4 and haven't a lot of checks and restrictions. It can execute only simple WITH queries like WITH tree AS (SELECT id,pnt,name,1::int AS level FROM t WHERE id=0 UNION SELECT t.id,t.pnt,t.name,tree.level+1 FROM t JOIN tree ON tree.id=t.pnt ) SELECT * FROM tree; It would be great if someone with knowledge of Pg internals can make a kind of code review and make some advices how to better implement all this. Regards, Evgen. ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [HACKERS] SQL99 Hierarchical queries
> Hi Evgen, > > How's the syncing with HEAD going? > > Cheers, > > Chris I'm working on it. Regards, Evgen. ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [HACKERS] SQL99 Hierarchical queries
Hi Evgen, How's the syncing with HEAD going? Cheers, Chris Evgen Potemkin wrote: Ok, I'm started porting it to 8.0.1 and will fix this also. By the way, did you know any test suit for such queries? To make some regression test. Regards, Evgen I tested you patch, and it's good work. I would all methods in PostgreSQL. I found query which kill backand WITH t AS ( SELECT 0::int AS i UNION ALL SELECT i + 1 FROM t WHERE i < 100) SELECT * FROM t; Regards Pavel Stehule ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [HACKERS] SQL99 Hierarchical queries
Hello hackers, > Thanks very much for doing this work. Is there some way you can > summarize what you did so others can join you in working on it? If it > is easier for you to write this in some language other than English, > please do, and we'll find translators :) > > I noticed that the patch touches the parser, the optimizer and the > executor. What does it to with each? What did I miss? > This is some info about implementations. Parser. WITH aliased queries stored as list of SUBQUERY nodes. Each of them is parsed as usually. In pstate->withClause already analyzed part of WITH queries list is stored. When next WITH subquery is analyzed, it's been added to subqueries list inside withClause node, so any WITH subquery can see al prevoius WITH subqueries. In FROM clause all WITH aliases represented by special type of RangTblEntry - RTE_WITH_SUBQUERY. It stores a reference to WithClause node and index of itself in QITH subqueries list. For analyzing var added step to search in WITH aliases if they are present. Recursiveness support. Before WITH subquery analyzing in pstate->withClause->calias stored it's alias. So when transforming FROM clause item and relation name found only in pstate->withClause->calias query marked as recursive. SQL99 recursive queries are made using UNION and first UNION subquery should be non recursive (this isn't currently checked). Thus when transforming set operation statement, after analyzing of first statement it's is RTE stored in pstate->withClause->cRTE, and all checks for vars in this WITH subquery in made against this RTE. Optimizer. WithClause node transformed to With node, scan of RTEs of type RTE_WITH_SUBQUERY to WithScan nodes. Each WITH subquery is enveloped into WithSubPlan node. It stores result and working tuplestores, and some flags (used for prevent double initialization and execution) for each subquery. Nothing extraordinary is done here. Executor. When executor tries to fetch first tuple from any WithScan node, this node check whether With node have been executed, if no then it executes it and then fetches all it's tuples from it's result tuplestore. "With" node being executed is simply call ExecNode on each subplan in it's list and storing tuples in result tuplestore. Recursiveness support. It's all done in Append node. If it marked as recusrive, it changes a little it's behaviour. Tuples fetched from subplan are stored in workin table. When Append reaches the end of list of its subqueries it call nodeWithSwitchTables. This function for query being executed will append result table to final table, move working table to result table, and clean working table. After this Append begins next loop of subqueries execution, starting from 2nd subquery. Thus first Append subquery is executed only once. Execution ends when no one tuple fetched from all subqueries. This approach allows WithScan nodes to fetch data fetched by Append in previous loop. Regards, Evgen. ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [HACKERS] SQL99 Hierarchical queries
> Thanks very much for doing this work. Is there some way you can > summarize what you did so others can join you in working on it? If it > is easier for you to write this in some language other than English, > please do, and we'll find translators :) > > I noticed that the patch touches the parser, the optimizer and the > executor. What does it to with each? What did I miss? > > Cheers, > D Ok, i'll make some doc on this topic. Regards, Evgen ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] SQL99 Hierarchical queries
> > Ok, I'm started porting it to 8.0.1 and will fix this also. > > By the way, did you know any test suit for such queries? To make some > > regression test. > > > Hello, I can find some examples on internet and prepare regression tests. > I think PostgreSQL can support all syntax H.Q. Is more easy created > question via Oracle syntax, and processing is faster (maybe better > optimalisation now), than ANSI WITH syntax. Can You add support for > clausule VALUE? > > Pavel Stehule On this weekend I'll see to DB2 reference and if there some description on what is it, I'll try to implement it. Regards, Evgen. ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] SQL99 Hierarchical queries
Mike, > I'm curious what kind of performance differences there would be over > using something like the nested-set model? > > Would this be faster, or slower? The answer is "yes".;-) Which tree structures you use depends on what you're trying to accomplish and what your use case is. There are some structures (for example, heirarchical org charts) for which nested sets can't be beat. There are plenty of reasons to implement other tree structures, such as graphs, cycles, and delimited lists depending on what you're trying to depict. What WITH is going to "replace", if anything, is the simple adjacency list structure. -- Josh Berkus Aglio Database Solutions San Francisco ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] SQL99 Hierarchical queries
On Mon, 28 Feb 2005, Evgen Potemkin wrote: > Ok, I'm started porting it to 8.0.1 and will fix this also. > By the way, did you know any test suit for such queries? To make some > regression test. > Hello, I can find some examples on internet and prepare regression tests. I think PostgreSQL can support all syntax H.Q. Is more easy created question via Oracle syntax, and processing is faster (maybe better optimalisation now), than ANSI WITH syntax. Can You add support for clausule VALUE? Pavel Stehule ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
Re: [HACKERS] SQL99 Hierarchical queries
I'm curious what kind of performance differences there would be over using something like the nested-set model? Would this be faster, or slower? On Thu, 2005-02-24 at 13:02 +0300, Evgen Potemkin wrote: > Hi hackers! > > I have done initial implementation of SQL99 WITH clause (attached). > It's now only for v7.3.4 and haven't a lot of checks and restrictions. > It can execute only simple WITH queries like > WITH tree AS (SELECT id,pnt,name,1::int AS level FROM t WHERE id=0 > UNION SELECT t.id,t.pnt,t.name,tree.level+1 FROM t JOIN tree ON > tree.id=t.pnt ) SELECT * FROM tree; > It would be great if someone with knowledge of Pg internals can make a > kind of code review and make some advices how to better implement all > this. > > Regards, Evgen. > ---(end of broadcast)--- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to [EMAIL PROTECTED] so that your > message can get through to the mailing list cleanly -- Mike Benoit <[EMAIL PROTECTED]> signature.asc Description: This is a digitally signed message part
Re: [HACKERS] SQL99 Hierarchical queries
On Mon, Feb 28, 2005 at 11:07:51AM +0300, Evgen Potemkin wrote: > Ok, I'm started porting it to 8.0.1 and will fix this also. By the > way, did you know any test suit for such queries? To make some > regression test. Evgen, Thanks very much for doing this work. Is there some way you can summarize what you did so others can join you in working on it? If it is easier for you to write this in some language other than English, please do, and we'll find translators :) I noticed that the patch touches the parser, the optimizer and the executor. What does it to with each? What did I miss? Cheers, D -- David Fetter [EMAIL PROTECTED] http://fetter.org/ phone: +1 510 893 6100 mobile: +1 415 235 3778 Remember to vote! ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [HACKERS] SQL99 Hierarchical queries
Ok, I'm started porting it to 8.0.1 and will fix this also. By the way, did you know any test suit for such queries? To make some regression test. Regards, Evgen > I tested you patch, and it's good work. I would all methods in PostgreSQL. > I found query which kill backand > > WITH t AS ( > SELECT 0::int AS i > UNION ALL SELECT i + 1 FROM t WHERE i < 100) > SELECT * FROM t; > > Regards > Pavel Stehule > > ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [HACKERS] SQL99 Hierarchical queries
hello, I tested you patch, and it's good work. I would all methods in PostgreSQL. I found query which kill backand WITH t AS ( SELECT 0::int AS i UNION ALL SELECT i + 1 FROM t WHERE i < 100) SELECT * FROM t; Regards Pavel Stehule ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] SQL99 Hierarchical queries
> > I have done initial implementation of SQL99 WITH clause (attached). > > It's now only for v7.3.4 and haven't a lot of checks and restrictions. > > What kind of restrictions are on it? Main restriction is that the query inside WITH alias can refer only to back and to itself. For example WITH a as (...),b as (...)select ...; a can refer only to itself, b - to a and b. Its needed to restrict WITH aliased query not to use WITH aliasing itself, i.e. avoid situation of WITH inside WITH. And make also some other checks. But this isn't done yet. Regards, Evgen. ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [HACKERS] SQL99 Hierarchical queries
I have done initial implementation of SQL99 WITH clause (attached). It's now only for v7.3.4 and haven't a lot of checks and restrictions. What kind of restrictions are on it? Chris ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
