Re: [HACKERS] [PERFORM] pgbench to the MAXINT
On 28.01.2013 23:30, Gurjeet Singh wrote: On Sat, Jan 26, 2013 at 11:24 PM, Satoshi Nagayasusn...@uptime.jp wrote: 2012/12/21 Gurjeet Singhsingh.gurj...@gmail.com: The patch is very much what you had posted, except for a couple of differences due to bit-rot. (i) I didn't have to #define MAX_RANDOM_VALUE64 since its cousin MAX_RANDOM_VALUE is not used by code anymore, and (ii) I used ternary operator in DDLs[] array to decide when to use bigint vs int columns. Please review. As for tests, I am currently running 'pgbench -i -s 21474' using unpatched pgbench, and am recording the time taken;Scale factor 21475 had actually failed to do anything meaningful using unpatched pgbench. Next I'll run with '-s 21475' on patched version to see if it does the right thing, and in acceptable time compared to '-s 21474'. What tests would you and others like to see, to get some confidence in the patch? The machine that I have access to has 62 GB RAM, 16-core 64-hw-threads, and about 900 GB of disk space. I have tested this patch, and hvae confirmed that the columns for aid would be switched to using bigint, instead of int, when the scalefactor= 20,000. (aid columns would exeed the upper bound of int when sf21474.) Also, I added a few fixes on it. - Fixed to apply for the current git master. - Fixed to surpress few more warnings about INT64_FORMAT. - Minor improvement in the docs. (just my suggestion) I attached the revised one. Looks good to me. Thanks! Ok, committed. At some point, we might want to have a strtoll() implementation in src/port. - Heikki -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
On Sat, Jan 26, 2013 at 11:24 PM, Satoshi Nagayasu sn...@uptime.jp wrote: Hi, I have reviewed this patch. https://commitfest.postgresql.org/action/patch_view?id=1068 2012/12/21 Gurjeet Singh singh.gurj...@gmail.com: The patch is very much what you had posted, except for a couple of differences due to bit-rot. (i) I didn't have to #define MAX_RANDOM_VALUE64 since its cousin MAX_RANDOM_VALUE is not used by code anymore, and (ii) I used ternary operator in DDLs[] array to decide when to use bigint vs int columns. Please review. As for tests, I am currently running 'pgbench -i -s 21474' using unpatched pgbench, and am recording the time taken;Scale factor 21475 had actually failed to do anything meaningful using unpatched pgbench. Next I'll run with '-s 21475' on patched version to see if it does the right thing, and in acceptable time compared to '-s 21474'. What tests would you and others like to see, to get some confidence in the patch? The machine that I have access to has 62 GB RAM, 16-core 64-hw-threads, and about 900 GB of disk space. I have tested this patch, and hvae confirmed that the columns for aid would be switched to using bigint, instead of int, when the scalefactor = 20,000. (aid columns would exeed the upper bound of int when sf21474.) Also, I added a few fixes on it. - Fixed to apply for the current git master. - Fixed to surpress few more warnings about INT64_FORMAT. - Minor improvement in the docs. (just my suggestion) I attached the revised one. Looks good to me. Thanks! -- Gurjeet Singh http://gurjeet.singh.im/
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Hi, I have reviewed this patch. https://commitfest.postgresql.org/action/patch_view?id=1068 2012/12/21 Gurjeet Singh singh.gurj...@gmail.com: The patch is very much what you had posted, except for a couple of differences due to bit-rot. (i) I didn't have to #define MAX_RANDOM_VALUE64 since its cousin MAX_RANDOM_VALUE is not used by code anymore, and (ii) I used ternary operator in DDLs[] array to decide when to use bigint vs int columns. Please review. As for tests, I am currently running 'pgbench -i -s 21474' using unpatched pgbench, and am recording the time taken;Scale factor 21475 had actually failed to do anything meaningful using unpatched pgbench. Next I'll run with '-s 21475' on patched version to see if it does the right thing, and in acceptable time compared to '-s 21474'. What tests would you and others like to see, to get some confidence in the patch? The machine that I have access to has 62 GB RAM, 16-core 64-hw-threads, and about 900 GB of disk space. I have tested this patch, and hvae confirmed that the columns for aid would be switched to using bigint, instead of int, when the scalefactor = 20,000. (aid columns would exeed the upper bound of int when sf21474.) Also, I added a few fixes on it. - Fixed to apply for the current git master. - Fixed to surpress few more warnings about INT64_FORMAT. - Minor improvement in the docs. (just my suggestion) I attached the revised one. Regards, -- Satoshi Nagayasu sn...@uptime.jp Uptime Technologies, LLC http://www.uptime.jp/ pgbench-64-v7.patch Description: Binary data -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
On Wed, Feb 16, 2011 at 8:15 AM, Greg Smith g...@2ndquadrant.com wrote: Tom Lane wrote: I think that might be a good idea --- it'd reduce the cross-platform variability of the results quite a bit, I suspect. random() is not to be trusted everywhere, but I think erand48 is pretty much the same wherever it exists at all (and src/port/ provides it elsewhere). Given that pgbench will run with threads in some multi-worker configurations, after some more portability research I think odds are good we'd get nailed by http://sourceware.org/**bugzilla/show_bug.cgi?id=10320http://sourceware.org/bugzilla/show_bug.cgi?id=10320: erand48 implementation not thread safe but POSIX says it should be. The AIX docs have a similar warning on them, so who knows how many versions of that library have the same issue. Maybe we could make sure the one in src/port/ is thread safe and make sure pgbench only uses it. This whole area continues to be messy enough that I think the patch needs to brew for another CF before it will all be sorted out properly. I'll mark it accordingly and can pick this back up later. Hi Greg, I spent some time rebasing this patch to current master. Attached is the patch, based on master couple of commits old. Your concern of using erand48() has been resolved since pgbench now uses thread-safe and concurrent pg_erand48() from src/port/. The patch is very much what you had posted, except for a couple of differences due to bit-rot. (i) I didn't have to #define MAX_RANDOM_VALUE64 since its cousin MAX_RANDOM_VALUE is not used by code anymore, and (ii) I used ternary operator in DDLs[] array to decide when to use bigint vs int columns. Please review. As for tests, I am currently running 'pgbench -i -s 21474' using unpatched pgbench, and am recording the time taken;Scale factor 21475 had actually failed to do anything meaningful using unpatched pgbench. Next I'll run with '-s 21475' on patched version to see if it does the right thing, and in acceptable time compared to '-s 21474'. What tests would you and others like to see, to get some confidence in the patch? The machine that I have access to has 62 GB RAM, 16-core 64-hw-threads, and about 900 GB of disk space. Linux host 3.2.6-3.fc16.ppc64 #1 SMP Fri Feb 17 21:41:20 UTC 2012 ppc64 ppc64 ppc64 GNU/Linux Best regards, PS: The primary source of patch is this branch: https://github.com/gurjeet/postgres/tree/64bit_pgbench -- Gurjeet Singh http://gurjeet.singh.im/ pgbencg-64-v6.patch Description: Binary data -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Tom Lane wrote: I think that might be a good idea --- it'd reduce the cross-platform variability of the results quite a bit, I suspect. random() is not to be trusted everywhere, but I think erand48 is pretty much the same wherever it exists at all (and src/port/ provides it elsewhere). Given that pgbench will run with threads in some multi-worker configurations, after some more portability research I think odds are good we'd get nailed by http://sourceware.org/bugzilla/show_bug.cgi?id=10320 : erand48 implementation not thread safe but POSIX says it should be. The AIX docs have a similar warning on them, so who knows how many versions of that library have the same issue. Maybe we could make sure the one in src/port/ is thread safe and make sure pgbench only uses it. This whole area continues to be messy enough that I think the patch needs to brew for another CF before it will all be sorted out properly. I'll mark it accordingly and can pick this back up later. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Greg Smith g...@2ndquadrant.com writes: Given that pgbench will run with threads in some multi-worker configurations, after some more portability research I think odds are good we'd get nailed by http://sourceware.org/bugzilla/show_bug.cgi?id=10320 : erand48 implementation not thread safe but POSIX says it should be. The AIX docs have a similar warning on them, so who knows how many versions of that library have the same issue. FWIW, I think that bug report is effectively complaining that if you use both drand48 and erand48, the former can impact the latter. If you use only erand48, I don't see that there's any problem. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
On Fri, Feb 11, 2011 at 8:35 AM, Stephen Frost sfr...@snowman.net wrote: Greg, * Tom Lane (t...@sss.pgh.pa.us) wrote: Greg Smith g...@2ndquadrant.com writes: Poking around a bit more, I just discovered another possible approach is to use erand48 instead of rand in pgbench, which is either provided by the OS or emulated in src/port/erand48.c That's way more resolution than needed here, given that 2^48 pgbench accounts would be a scale of 2.8M, which makes for a database of about 42 petabytes. I think that might be a good idea --- it'd reduce the cross-platform variability of the results quite a bit, I suspect. random() is not to be trusted everywhere, but I think erand48 is pretty much the same wherever it exists at all (and src/port/ provides it elsewhere). Works for me. Greg, will you be able to work on this change? If not, I might be able to. Seeing as how this patch has not been updated, I think it's time to mark this one Returned with Feedback. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Greg, * Tom Lane (t...@sss.pgh.pa.us) wrote: Greg Smith g...@2ndquadrant.com writes: Poking around a bit more, I just discovered another possible approach is to use erand48 instead of rand in pgbench, which is either provided by the OS or emulated in src/port/erand48.c That's way more resolution than needed here, given that 2^48 pgbench accounts would be a scale of 2.8M, which makes for a database of about 42 petabytes. I think that might be a good idea --- it'd reduce the cross-platform variability of the results quite a bit, I suspect. random() is not to be trusted everywhere, but I think erand48 is pretty much the same wherever it exists at all (and src/port/ provides it elsewhere). Works for me. Greg, will you be able to work on this change? If not, I might be able to. Thanks, Stephen signature.asc Description: Digital signature
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Stephen Frost wrote: Just wondering, did you consider just calling random() twice and smashing the result together..? I did. The problem is that even within the 32 bits that random() returns, it's not uniformly distributed. Combining two of them isn't really going to solve the distribution problem, just move it around. Some number of lower-order bits are less random than the others, and which they are is implementation dependent. Poking around a bit more, I just discovered another possible approach is to use erand48 instead of rand in pgbench, which is either provided by the OS or emulated in src/port/erand48.c That's way more resolution than needed here, given that 2^48 pgbench accounts would be a scale of 2.8M, which makes for a database of about 42 petabytes. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us PostgreSQL 9.0 High Performance: http://www.2ndQuadrant.com/books -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Greg Smith g...@2ndquadrant.com writes: Poking around a bit more, I just discovered another possible approach is to use erand48 instead of rand in pgbench, which is either provided by the OS or emulated in src/port/erand48.c That's way more resolution than needed here, given that 2^48 pgbench accounts would be a scale of 2.8M, which makes for a database of about 42 petabytes. I think that might be a good idea --- it'd reduce the cross-platform variability of the results quite a bit, I suspect. random() is not to be trusted everywhere, but I think erand48 is pretty much the same wherever it exists at all (and src/port/ provides it elsewhere). regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Attached is an updated 64-bit pgbench patch that works as expected for all of the most common pgbench operations, including support for scales above the previous boundary of just over 21,000. Here's the patched version running against a 303GB database with a previously unavailable scale factor: $ pgbench -T 300 -j 2 -c 4 pgbench starting vacuum...end. transaction type: TPC-B (sort of) scaling factor: 25000 query mode: simple number of clients: 4 number of threads: 2 duration: 300 s number of transactions actually processed: 21681 tps = 72.24 (including connections establishing) tps = 72.250610 (excluding connections establishing) And some basic Q/A that the values it touched were in the right range: $ psql -d pgbench -c select min(aid),max(aid) from pgbench_accounts; min |max -+ 1 | 25 $ psql -d pgbench -c select min(aid),max(aid),count(*) from pgbench_accounts where abalance!=0 min |max | count ---++--- 51091 | 2499989587 | 21678 (This system was doing 300MB/s on reads while executing that count, and it still took 19 minutes) The clever way Euler updated the patch, you don't pay for the larger on-disk data (bigint columns) unless you use a range that requires it, which greatly reduces the number of ways the test results can suffer from this change. I felt the way that was coded was a bit more complicated than it needed to be though, as it made where that switch happened at get computed at runtime based on the true size of the integers. I took that complexity out and just put a hard line in there instead: if scale=2, you get bigints. That's not very different from the real limit, and it made documenting when the switch happens easy to write and to remember. The main performance concern with this change was whether using int64 more internally for computations would slow things down on a 32-bit system. I thought I'd test that on my few years old laptop. It turns out that even though I've been running an i386 Linux on here, it's actually a 64-bit CPU. (I think that it has a 32-bit install may be an artifact of Adobe Flash install issues, sadly) So this may not be as good of a test case as I'd hoped. Regardless, running a test aimed to stress simple SELECTs, the thing I'd expect to suffer most from additional CPU overhead, didn't show any difference in performance: $ createdb pgbench $ pgbench -i -s 10 pgbench $ psql -c show shared_buffers shared_buffers 256MB (1 row) $ pgbench -S -j 2 -c 4 -T 60 pgbench i386x86_64 69326924 69236926 69236922 66886772 69146791 69026916 69176909 69436837 66896744 66886744min 69436926max 68706860average Given the noise level of pgbench tests, I'm happy saying that is the same speed. I suspect the real overhead in pgbench's processing relates to how it is constantly parsing text to turn them into statements, and that how big the integers it uses are is barley detectable over that. So...where does that leave this patch? I feel that pgbench will become less relevant very quickly in 9.1 unless something like this is committed. And there don't seem to be significant downsides to this in terms of performance. There are however a few rough points left in here that might raise concern: 1) A look into the expected range of the rand() function suggests the glibc implementation normally proves 30 bits of resolution, so about 1 billion numbers. You'll have 1B rows in a pgbench database once the scale goes over 10,000. So without a major overhaul of how random number generation is treated here, people can expect the distribution of rows touched by a test run to get less even once the database scale gets very large. I added another warning paragraph to the end of the docs in this update to mention this. Long-term, I suspect we may need to adopt a superior 64-bit RNG approach, something like a Mersenne Twister perhaps. That's a bit more than can be chewed on during 9.1 development though. 2) I'd rate odds are good there's one or more corner-case bugs in \setrandom or \setshell I haven't found yet, just from the way that code was converted. Those have some changes I haven't specifically tested exhaustively yet. I don't see any issues when running the most common two pgbench tests, but that's doesn't mean every part of that 32 - 64 bit conversion was done correctly. Given how I use pgbench, for data generation and rough load testing, I'd say neither of those concerns outweights the need to expand the size range of this program. I would be happy to see this go in, followed by some alpha and beta testing aimed to see if any of the rough spots I'm concerned about actually appear. Unfortunately I can't fit all of those tests in right now, as throwing around one of these 300GB data sets is painful--when you're only
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Greg, * Greg Smith (g...@2ndquadrant.com) wrote: I took that complexity out and just put a hard line in there instead: if scale=2, you get bigints. That's not very different from the real limit, and it made documenting when the switch happens easy to write and to remember. Agreed completely on this. It turns out that even though I've been running an i386 Linux on here, it's actually a 64-bit CPU. (I think that it has a 32-bit install may be an artifact of Adobe Flash install issues, sadly) So this may not be as good of a test case as I'd hoped. Actually, I would think it'd still be sufficient.. If you're under a 32bit kernel you're not going to be using the extended registers, etc, that would be available under a 64bit kernel.. That said, the idea that we should care about 32-bit systems these days, in a benchmarking tool, is, well, silly, imv. 1) A look into the expected range of the rand() function suggests the glibc implementation normally proves 30 bits of resolution, so about 1 billion numbers. You'll have 1B rows in a pgbench database once the scale goes over 10,000. So without a major overhaul of how random number generation is treated here, people can expect the distribution of rows touched by a test run to get less even once the database scale gets very large. Just wondering, did you consider just calling random() twice and smashing the result together..? I added another warning paragraph to the end of the docs in this update to mention this. Long-term, I suspect we may need to adopt a superior 64-bit RNG approach, something like a Mersenne Twister perhaps. That's a bit more than can be chewed on during 9.1 development though. I tend to agree that we should be able to improve the random number generation in the future. Additionally, imv, we should be able to say pg_bench version X isn't comparable to version Y in the release notes or something, or have seperate version #s for it which make it clear what can be compared to each other and what can't. Painting ourselves into a corner by saying we can't ever make pgbench generate results that can't be compared to every other released version of pgbench just isn't practical. 2) I'd rate odds are good there's one or more corner-case bugs in \setrandom or \setshell I haven't found yet, just from the way that code was converted. Those have some changes I haven't specifically tested exhaustively yet. I don't see any issues when running the most common two pgbench tests, but that's doesn't mean every part of that 32 - 64 bit conversion was done correctly. I'll take a look. :) Thanks, Stephen signature.asc Description: Digital signature
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
The update on the work to push towards a bigger pgbench is that I now
have the patch running and generating databases larger than any
previously possible scale:
$ time pgbench -i -s 25000 pgbench
...
25 tuples done.
...
real258m46.350s
user14m41.970s
sys0m21.310s
$ psql -d pgbench -c select
pg_size_pretty(pg_relation_size('pgbench_accounts'));
pg_size_pretty
313 GB
$ psql -d pgbench -c select
pg_size_pretty(pg_relation_size('pgbench_accounts_pkey'));
pg_size_pretty
52 GB
$ time psql -d pgbench -c select count(*) from pgbench_accounts
count
25
real18m48.363s
user0m0.010s
sys0m0.000s
The only thing wrong with the patch sent already needed to reach this
point was this line:
for (k = 0; k naccounts * scale; k++)
Which needed a (int64) cast for the multiplied value in the middle there.
Unfortunately the actual test itself doesn't run yet. Every line I see
when running the SELECT-only test says:
client 0 sending SELECT abalance FROM pgbench_accounts WHERE aid = 1;
So something about the updated random generation code isn't quite right
yet. Now that I have this monster built, I'm going to leave it on the
server until I can sort that out, which hopefully will finish up in the
next day or so.
--
Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
PostgreSQL 9.0 High Performance: http://www.2ndQuadrant.com/books
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Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Robert Haas wrote: At least in my book, we need to get this committed in the next two weeks, or wait for 9.2. Yes, I was just suggesting that I was not going to get started in the first week or two given the other pgbench related tests I had queued up already. Those are closing up nicely, and I'll start testing performance of this change over the weekend. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us PostgreSQL 9.0 High Performance: http://www.2ndQuadrant.com/books -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
On Tue, Jan 18, 2011 at 1:42 PM, Greg Smith g...@2ndquadrant.com wrote: Thanks for picking this up again and finishing the thing off. I'll add this into my queue of performance tests to run and we can see if this is worth applying. Probably take a little longer than the usual CF review time. But as this doesn't interfere with other code people are working on and is sort of a bug fix, I don't think it will be a problem if it takes a little longer to get this done. At least in my book, we need to get this committed in the next two weeks, or wait for 9.2. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Euler Taveira de Oliveira wrote: (i) If we want to support and scale factor greater than 21474 we have to convert some columns to bigint; it will change the test. From the portability point it is a pity but as we have never supported it I'm not too worried about it. Why? Because it will use bigint columns only if the scale factor is greater than 21474. Is it a problem? I don't think so because generally people compare tests with the same scale factor. (ii) From the performance perspective, we need to test if the modifications don't impact performance. I don't create another code path for 64-bit modifications (it is too ugly) and I'm afraid some modifications affect the 32-bit performance. I'm in a position to test it though because I don't have a big machine ATM. Greg, could you lead these tests? (iii) I decided to copy scanint8() (called strtoint64 there) from backend (Robert suggestion [1]) because Tom pointed out that strtoll() has portability issues. I replaced atoi() with strtoint64() but didn't do any performance tests. (i): Completely agreed. (ii): There is no such thing as a big machine that is 32 bits now; anything that's 32 is a tiny system here in 2011. What I can do is check for degredation on the only 32-bit system I have left here, my laptop. I'll pick a sensitive test case and take a look. (iii) This is an important thing to test, particularly given it has the potential to impact 64-bit results too. Thanks for picking this up again and finishing the thing off. I'll add this into my queue of performance tests to run and we can see if this is worth applying. Probably take a little longer than the usual CF review time. But as this doesn't interfere with other code people are working on and is sort of a bug fix, I don't think it will be a problem if it takes a little longer to get this done. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us PostgreSQL 9.0 High Performance: http://www.2ndQuadrant.com/books -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] pgbench to the MAXINT
Em 10-01-2011 05:25, Greg Smith escreveu:
Euler Taveira de Oliveira wrote:
Em 07-01-2011 22:59, Greg Smith escreveu:
setrandom: invalid maximum number -2147467296
It is failing at atoi() circa pgbench.c:1036. But it just the first
one. There are some variables and constants that need to be converted
to int64 and some functions that must speak 64-bit such as getrand().
Are you working on a patch?
http://archives.postgresql.org/pgsql-hackers/2010-01/msg02868.php
http://archives.postgresql.org/message-id/4c326f46.4050...@2ndquadrant.com
Greg, I just improved your patch. I tried to work around the problems pointed
out in the above threads. Also, I want to raise some points:
(i) If we want to support and scale factor greater than 21474 we have to
convert some columns to bigint; it will change the test. From the portability
point it is a pity but as we have never supported it I'm not too worried about
it. Why? Because it will use bigint columns only if the scale factor is
greater than 21474. Is it a problem? I don't think so because generally people
compare tests with the same scale factor.
(ii) From the performance perspective, we need to test if the modifications
don't impact performance. I don't create another code path for 64-bit
modifications (it is too ugly) and I'm afraid some modifications affect the
32-bit performance. I'm in a position to test it though because I don't have a
big machine ATM. Greg, could you lead these tests?
(iii) I decided to copy scanint8() (called strtoint64 there) from backend
(Robert suggestion [1]) because Tom pointed out that strtoll() has portability
issues. I replaced atoi() with strtoint64() but didn't do any performance tests.
Comments?
[1] http://archives.postgresql.org/pgsql-hackers/2010-07/msg00173.php
--
Euler Taveira de Oliveira
http://www.timbira.com/
diff --git a/contrib/pgbench/pgbench.c b/contrib/pgbench/pgbench.c
index 7c2ca6e..e9eb720 100644
*** a/contrib/pgbench/pgbench.c
--- b/contrib/pgbench/pgbench.c
***
*** 60,65
--- 60,67
#define INT64_MAX INT64CONST(0x7FFF)
#endif
+ #define MAX_RANDOM_VALUE64 INT64_MAX
+
/*
* Multi-platform pthread implementations
*/
*** usage(const char *progname)
*** 364,378
progname, progname);
}
/* random number generator: uniform distribution from min to max inclusive */
! static int
! getrand(int min, int max)
{
/*
* Odd coding is so that min and max have approximately the same chance of
* being selected as do numbers between them.
*/
! return min + (int) (((max - min + 1) * (double) random()) / (MAX_RANDOM_VALUE + 1.0));
}
/* call PQexec() and exit() on failure */
--- 366,451
progname, progname);
}
+ /*
+ * strtoint64 -- convert a string to 64-bit integer
+ *
+ * this function is a modified version of scanint8() from
+ * src/backend/utils/adt/int8.c.
+ *
+ * XXX should it have a return value?
+ *
+ */
+ static int64
+ strtoint64(const char *str)
+ {
+ const char *ptr = str;
+ int64 result = 0;
+ int sign = 1;
+
+ /*
+ * Do our own scan, rather than relying on sscanf which might be broken
+ * for long long.
+ */
+
+ /* skip leading spaces */
+ while (*ptr isspace((unsigned char) *ptr))
+ ptr++;
+
+ /* handle sign */
+ if (*ptr == '-')
+ {
+ ptr++;
+
+ /*
+ * Do an explicit check for INT64_MIN. Ugly though this is, it's
+ * cleaner than trying to get the loop below to handle it portably.
+ */
+ if (strncmp(ptr, 9223372036854775808, 19) == 0)
+ {
+ result = -INT64CONST(0x7fff) - 1;
+ ptr += 19;
+ goto gotdigits;
+ }
+ sign = -1;
+ }
+ else if (*ptr == '+')
+ ptr++;
+
+ /* require at least one digit */
+ if (!isdigit((unsigned char) *ptr))
+ fprintf(stderr, invalid input syntax for integer: \%s\\n, str);
+
+ /* process digits */
+ while (*ptr isdigit((unsigned char) *ptr))
+ {
+ int64 tmp = result * 10 + (*ptr++ - '0');
+
+ if ((tmp / 10) != result) /* overflow? */
+ fprintf(stderr, value \%s\ is out of range for type bigint\n, str);
+ result = tmp;
+ }
+
+ gotdigits:
+
+ /* allow trailing whitespace, but not other trailing chars */
+ while (*ptr != '\0' isspace((unsigned char) *ptr))
+ ptr++;
+
+ if (*ptr != '\0')
+ fprintf(stderr, invalid input syntax for integer: \%s\\n, str);
+
+ return ((sign 0) ? -result : result);
+ }
+
/* random number generator: uniform distribution from min to max inclusive */
! static int64
! getrand(int64 min, int64 max)
{
/*
* Odd coding is so that min and max have approximately the same chance of
* being selected as do numbers between them.
*/
! return min + (int64) (((max - min + 1) * (double) random()) / (MAX_RANDOM_VALUE64 + 1.0));
}
/* call PQexec() and exit() on failure */
*** top:
*** 887,893
if (commands[st-state] == NULL)
{
st-state = 0;
! st-use_file = getrand(0,
