Re: Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-08 Thread Hans-Jürgen Schönig
Jim Buttafuoco wrote: >Is this NOT what I have been after for many months now. I dropped the >tablespace/location idea before 7.2 because that >didn't seem to be any interest. Please see my past email's for the SQL commands and >on disk directory layout I have >proposed. I have a working 7.2

Re: Parallel Executors [was RE: [HACKERS] Threaded Sorting]

2002-10-07 Thread Curtis Faith
> Curtis Faith wrote: > > > The current transaction/user state seems to be stored in process > > global space. This could be changed to be a sointer to a struct > > stored in a back-end specific shared memory area which would be > > accessed by the executor process at execution start. The backend

Re: Parallel Executors [was RE: [HACKERS] Threaded Sorting]

2002-10-07 Thread Jan Wieck
Curtis Faith wrote: > The current transaction/user state seems to be stored in process > global space. This could be changed to be a sointer to a struct > stored in a back-end specific shared memory area which would be > accessed by the executor process at execution start. The backend > would des

Re: Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-07 Thread Jim Buttafuoco
Is this NOT what I have been after for many months now. I dropped the tablespace/location idea before 7.2 because that didn't seem to be any interest. Please see my past email's for the SQL commands and on disk directory layout I have proposed. I have a working 7.2 system with tablespaces/loc

Re: Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-07 Thread Hans-Jürgen Schönig
> > Quotas are handled differently on ever platform (if available). >>>Yeah. But that's sysadmins responsibility not DBA's. >>> >>> >>Maybe many people ARE the sysadmins of their PostgreSQL box ... >>When developing a database with an open mind people should try to see

Re: Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-07 Thread Tom Lane
=?ISO-8859-1?Q?Hans-J=FCrgen_Sch=F6nig?= <[EMAIL PROTECTED]> writes: > how would you handle table spaces? The plan that's been discussed simply defines a tablespace as being a directory somewhere; physical storage of individual tables would remain basically the same, one or more files under the c

Re: Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-07 Thread Shridhar Daithankar
On 7 Oct 2002 at 16:49, Hans-Jürgen Schönig wrote: > >Mount a directory on a partition. If the data exceeds on that partition, there > >would be disk error. Like tablespace getting overflown. I have seen both the > >scenarios in action.. > Of course it can be done somehow. However, with tablesp

Re: Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-07 Thread Hans-Jürgen Schönig
>>>2) What a directory structure does not offer that table space does? >>> >>> >>You need to the command line in order to manage quotas - you might not >>want that. >> >> > >Mount a directory on a partition. If the data exceeds on that partition, there >would be disk error. Like table

Re: Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-07 Thread Shridhar Daithankar
On 7 Oct 2002 at 15:52, Hans-Jürgen Schönig wrote: > >Can anybody please tell me in detail.(Not just a pointing towards TODO items) > >1) What a table space supposed to offer? > They allow you to define a maximum amount of storage for a certain set > of data. Use quota > They help you to defin

Re: Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-07 Thread Hans-Jürgen Schönig
> > >Can anybody please tell me in detail.(Not just a pointing towards TODO items) > >1) What a table space supposed to offer? > They allow you to define a maximum amount of storage for a certain set of data. They help you to define the location of data. They help you to define how much data can

Table spaces again [was Re: [HACKERS] Threaded Sorting]

2002-10-07 Thread Shridhar Daithankar
On 4 Oct 2002 at 21:13, Hans-Jürgen Schönig wrote: > Bingo = great :). > The I/O problem seems to be solved :). > > A table space concept would be top of the histlist :). > > The symlink version is not very comfortable and I think it would be a > real hack. > Also: If we had a clean table spac

Re: [HACKERS] Threaded Sorting

2002-10-07 Thread Hans-Jürgen Schönig
Threads are bad - I know ... I like the idea of a pool of processes instead of threads - from my point of view this would be useful. I am planning to run some tests (GEQO, AIX, sorts) as soon as I have time to do so (still too much work ahead before :( ...). If I had time I'd love to do somethi

Re: [HACKERS] Threaded Sorting

2002-10-07 Thread Hans-Jürgen Schönig
Threads are not the best solutions when it comes to portability. A prefer a process model as well. My concern was that a process model might be a bit too slow for that but if we had processes in memory this would be wonderful thing. Using it for small amounts of data is pretty useless - I totall

Re: [HACKERS] Threaded Sorting

2002-10-07 Thread Hans-Jürgen Schönig
Greg Copeland wrote: >I wouldn't hold your breath for any form of threading. Since PostgreSQL >is process based, you might consider having a pool of sort processes >which address this but I doubt you'll get anywhere talking about threads >here. > >Greg > > > I came across the problem yesterda

Re: [HACKERS] Threaded Sorting

2002-10-07 Thread Hans-Jürgen Schönig
Bingo = great :). The I/O problem seems to be solved :). A table space concept would be top of the histlist :). The symlink version is not very comfortable and I think it would be a real hack. Also: If we had a clean table space concept it would be real advantage. In the first place it would be

Parallel Executors [was RE: [HACKERS] Threaded Sorting]

2002-10-06 Thread Curtis Faith
tom lane wrote: > "Curtis Faith" <[EMAIL PROTECTED]> writes: > > What about splitting out parsing, optimization and plan generation from > > execution and having a separate pool of exececutor processes. > > > As an optimizer finished with a query plan it would initiate execution > > by grabbing a

Re: [HACKERS] Threaded Sorting

2002-10-05 Thread Tom Lane
"Curtis Faith" <[EMAIL PROTECTED]> writes: > What about splitting out parsing, optimization and plan generation from > execution and having a separate pool of exececutor processes. > As an optimizer finished with a query plan it would initiate execution > by grabbing an executor from a pool and p

Re: [HACKERS] Threaded Sorting

2002-10-05 Thread Curtis Faith
tom lane writes: >The notion of a sort process pool seems possibly attractive. I'm >unconvinced that it's going to be a win though because of the cost of >shoving data across address-space boundaries. What about splitting out parsing, optimization and plan generation from execution and having

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
Tom Lane wrote: > Bruce Momjian <[EMAIL PROTECTED]> writes: > > Tom Lane wrote: > >> ... But ISTM that if this makes sense for > >> our internal temp files, it makes sense for user-created temp tables > >> as well. > > > Yes, I was thinking that, but of course, those are real tables, rather > >

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Greg Copeland
On Fri, 2002-10-04 at 15:07, Tom Lane wrote: > the sort comparison function can be anything, including user-defined > code that does database accesses or other interesting stuff. This This is something that I'd not considered. > would mean that the sort auxiliary process would have to adopt the

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Tom Lane
Greg Copeland <[EMAIL PROTECTED]> writes: > ... I can understand why > addressing the seemingly more common I/O bound case would receive > priority, however, I'm at a loss as to why the other would be completely > ignored. Bruce already explained that we avoid threads because of portability and r

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Tom Lane
Bruce Momjian <[EMAIL PROTECTED]> writes: > Tom Lane wrote: >> ... But ISTM that if this makes sense for >> our internal temp files, it makes sense for user-created temp tables >> as well. > Yes, I was thinking that, but of course, those are real tables, rather > than just files. Not sure how c

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Greg Copeland
On Fri, 2002-10-04 at 14:31, Bruce Momjian wrote: > We use tape sorts, ala Knuth, meaning we sort in memory as much as > possible, but when there is more data than fits in memory, rather than > swapping, we write to temp files then merge the temp files (aka tapes). Right, which is what I original

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
Tom Lane wrote: > Bruce Momjian <[EMAIL PROTECTED]> writes: > > Tom, what temp files do we use that aren't for sorting; I forgot. > > MATERIALIZE plan nodes are the only thing I can think of offhand that > uses a straight temp file. But ISTM that if this makes sense for > our internal temp file

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
Greg Copeland wrote: -- Start of PGP signed section. > Well, that's why I was soliciting developer input as to exactly what > goes on with sorts. From what I seem to be hearing, all sorts result in > temp files being created and/or used. If that's the case then yes, I > can understand the fixati

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Tom Lane
Bruce Momjian <[EMAIL PROTECTED]> writes: > Tom, what temp files do we use that aren't for sorting; I forgot. MATERIALIZE plan nodes are the only thing I can think of offhand that uses a straight temp file. But ISTM that if this makes sense for our internal temp files, it makes sense for user-c

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Greg Copeland
Well, that's why I was soliciting developer input as to exactly what goes on with sorts. From what I seem to be hearing, all sorts result in temp files being created and/or used. If that's the case then yes, I can understand the fixation. Of course that opens the door for it being a horrible im

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
Greg Copeland wrote: -- Start of PGP signed section. > I see. I just always assumed that it would be done as part of table > space effort as it's such a defacto feature. > > I am curious as to why no one has commented on the other rather obvious > performance enhancement which was brought up in

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Greg Copeland
I see. I just always assumed that it would be done as part of table space effort as it's such a defacto feature. I am curious as to why no one has commented on the other rather obvious performance enhancement which was brought up in this thread. Allowing for parallel sorting seems rather obviou

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
Greg Copeland wrote: -- Start of PGP signed section. > On Fri, 2002-10-04 at 12:26, Bruce Momjian wrote: > > Added to TODO: > > > > * Allow sorting to use multiple work directories > > Why wouldn't that fall under the table space effort??? Yes, but we make it a separate item so we are sure

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
Tom Lane wrote: > Bruce Momjian <[EMAIL PROTECTED]> writes: > > Bingo! Want to increase sorting performance, give it more I/O > > bandwidth, and it will take 1/100th of the time to do threading. > > > Added to TODO: > > * Allow sorting to use multiple work directories > > Yeah, I like that.

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Greg Copeland
On Fri, 2002-10-04 at 12:26, Bruce Momjian wrote: > Added to TODO: > > * Allow sorting to use multiple work directories Why wouldn't that fall under the table space effort??? Greg signature.asc Description: This is a digitally signed message part

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Tom Lane
Bruce Momjian <[EMAIL PROTECTED]> writes: > Bingo! Want to increase sorting performance, give it more I/O > bandwidth, and it will take 1/100th of the time to do threading. > Added to TODO: > * Allow sorting to use multiple work directories Yeah, I like that. Actually it should apply to

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Justin Clift
Bruce Momjian wrote: > > scott.marlowe wrote: > > It seems like sometimes we consider these issues more from the one or two > > SCSI drives perspective insted of the big box o drives perspective. > > Yes, it is mostly for non-RAID drives, but also, sometimes single drives > can be faster. When

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
scott.marlowe wrote: > > We haven't thought about it yet because there are too many buggy thread > > implementations. We are probably just now getting to a point where we > > can consider it. However, lots of databases have moved to threads for > > all sorts of things and ended up with a royal m

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
Hans-Jürgen Schönig wrote: > Threads are bad - I know ... > I like the idea of a pool of processes instead of threads - from my > point of view this would be useful. > > I am planning to run some tests (GEQO, AIX, sorts) as soon as I have > time to do so (still too much work ahead before :( ...

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread scott.marlowe
On Fri, 4 Oct 2002, Bruce Momjian wrote: > Hans-Jürgen Schönig wrote: > > Did anybody think about threaded sorting so far? > > Assume an SMP machine. In the case of building an index or in the case > > of sorting a lot of data there is just one backend working. Therefore > > just one CPU is use

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Bruce Momjian
Hans-Jürgen Schönig wrote: > Did anybody think about threaded sorting so far? > Assume an SMP machine. In the case of building an index or in the case > of sorting a lot of data there is just one backend working. Therefore > just one CPU is used. > What about starting a thread for every temporar

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Greg Copeland
On Fri, 2002-10-04 at 10:37, Hans-Jürgen Schönig wrote: > My concern was that a process model might be a bit too slow for that but > if we had processes in memory this would be wonderful thing. Yes, that's the point of having a pool. The idea is not only do you avoid process creation and destru

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Greg Copeland
On Fri, 2002-10-04 at 09:40, Hans-Jürgen Schönig wrote: > > I had a brief look at the code used for sorting. It is very well > documented so maybe it is worth thinking about a parallel algorithm. > > When talking about threads: A pool of processes for sorting? Maybe this > could be useful but

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Greg Copeland
I wouldn't hold your breath for any form of threading. Since PostgreSQL is process based, you might consider having a pool of sort processes which address this but I doubt you'll get anywhere talking about threads here. Greg On Fri, 2002-10-04 at 02:46, Hans-Jürgen Schönig wrote: > Did anybody

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Tom Lane
=?ISO-8859-1?Q?Hans-J=FCrgen_Sch=F6nig?= <[EMAIL PROTECTED]> writes: > Did anybody think about threaded sorting so far? > Assume an SMP machine. In the case of building an index or in the case > of sorting a lot of data there is just one backend working. Therefore > just one CPU is used. > What

Re: [HACKERS] Threaded Sorting

2002-10-04 Thread Shridhar Daithankar
On 4 Oct 2002 at 9:46, Hans-Jürgen Schönig wrote: > Did anybody think about threaded sorting so far? > Assume an SMP machine. In the case of building an index or in the case > of sorting a lot of data there is just one backend working. Therefore > just one CPU is used. > What about starting a t

[HACKERS] Threaded Sorting

2002-10-04 Thread Hans-Jürgen Schönig
Did anybody think about threaded sorting so far? Assume an SMP machine. In the case of building an index or in the case of sorting a lot of data there is just one backend working. Therefore just one CPU is used. What about starting a thread for every temporary file being created? This way CREAT