Looking at this thread - the patch is obviously right. It doesn't matter about NFS, Linux, or any host of random crap people brought up. (I unfortunately suspect if you hadn't mentioned any of that, and just said "write doesn't guarantee full writes, this handles that" it may have gone better).
The documentation (literally on every system) is quite clear:
"The return value is the number of bytes actually written. This may be size, but can always be smaller. Your program should always call write in a loop, iterating until all the data is written."
(see https://www.gnu.org/software/libc/manual/html_node/I_002fO-P...)
Literally all documentation you can find about write on all systems that implement it clearly mentions it doesn't have to write all the bytes you ask it to.
Instead of saying "yeah, that's right", people go off in every random direction, with people arguing about your NFS mount options, what things can cause write to do that and whether they are possible[1] or they should care about them.
Sigh.
[1] spoiler alert: it doesn't matter. The API allows for this, you need to handle it.
> Instead of saying "yeah, that's right", people go off in every random direction, with people arguing about your NFS mount options, what things can cause write to do that and whether they are possible[1] or they should care about them.
Given that changing the mount option solved the immediate problem for the OP, I fail to see how it's random.
> [1] spoiler alert: it doesn't matter. The API allows for this, you need to handle it.
Sure, it's not like the return value was ignored before though. I agree retrying is the better response, but erroring out is a form of handling (and will also lead to retries in several places, just with a loop that's not tightly around the write()).
It's random because pretty much anyone could volunteer that opinion. By diagnosing the problem, making a patch and reaching out the author has already made their intention of fixing the problem clear. Unless it has been established that the problem isn't valid a workaround isn't really relevant.
Effective communication and exchange of ideas needs to have a good ratio between work and value. I used to frequent meetups where people would present projects with thousands of hours or work and priorities behind them. There would almost always be someone with less experience stating their "ideas" on what should be done instead. Eventually those people would end up talking among themselves where their ideas could flow freely without any restriction of actual work being done.
Experienced people provide value. They try to understand the problem, add their own experience to it and validate the work that has already been done. They make the problem smaller and closer to a solution. They don't, or shouldn't, casually increase the scope for little reason.
I'm baffled by this. Even if the fix had been immediately committed, the workaround of using nointr still would have been valuable, because a fixed version of postgres wouldn't immediately have been released.
You seem to argue in a way that entirely counteract your own later comments.
It is often the same with software. Good feedback on software isn't random ideas, suggestions or feature requests that adds hundreds of hours of work on a whim. It is feedback that considers the work that has already been done. Anyone can come up with something else, especially in theory and with a blank slate. It doesn't really require anything other than an opinion. Hacker News certainly is proof of that.
You keep making my point. All you have is defensive, deflecting and rude comments. If you disagree with something it isn't hard to say "I disagree that x is y because z", like anyone interested in a discussion would. I will keep this in mind when interacting with the community, commissioning work or buying services related to Postgres comes across my desk.
Note that you're the one hiding behind at least the third sockpuppet account.
I am not hiding anymore than any other anonymous account and for no other reason than time management and privacy. I shouldn't frequent hacker news for reasons previously stated, but sometimes I tell myself that the decent thing is to reply. Especially as many people won't. Now it is clear that this discussion isn't going anywhere so I won't be creating any other accounts or comments. To prevent any ambiguity this won't change.
In this case it is “a form” but that specific handling is provably wrong. That is important: everybody could have tried and proved again. Therefore just dismissing the correct handling and keeping the wrong one is, let me repeat, also provably wrong.
> 1. If writes need to be retried, why not reads? (No, that's not an invitation to expand the scope of the patch; it's a question about NFS implementation.)
and
> 4. As coded, the patch behaves incorrectly if you get a zero return on a retry. If we were going to do this, I think we'd need to absorb the errno-munging currently done by callers into the writeAll function.
not review comments?
> when the problem clearly lies in the code not following the specs.
There were plenty of questions about how exactly the fix should look like below
https://www.postgresql.org/message-id/AD4A13A5-8778-4D94-BBB...
How's that not review?
Callers would still need to be informed that a partial write occurred and would need to do something about it.
Someone comes along with a patch or idea. Bunch of big Postgres people come knock it and it dies right there.
Happened to me when I suggested a more multi-tenant approach back around 2010 and today we have Citus. I was told that (paraphrased) no users were asking for that sort of thing.
I see it kind of happening with the Foreign Key Array patch that the author asked for help to rebase and no one bothered to reply.
Someone suggested replacing the Postmaster with a threaded approach so it could scale better (and showed benchmarks of their implementation handling more connections). Community response was there were already 3rd party connection pools that do the job. An outsider looking in considers this nuts - most people would not run additional components if they did not need to!
Another example: NAMEDATALEN restricts every identifier to 63 bytes - a limit that causes frequent issues (more so now that we have partitioning) and also a problem for multi-lingual table names. It’s been proposed to increase this limit a few times. Every time the answer has been: abbreviate your table names or recompile your own version of Postgres.
Could name a few other examples too I’ve noticed over the years and just sighed at. I don’t expect every idea to be accepted or even welcomed - but there is that sense of bias against change.
I even saw something similar when I went to the ER recently. Even doctors will pickup on one thing you say and draw conclusions from that and dismiss everything else.
This pattern seems really common, and is what scares me about the future in general. The 'experts' concentrate on the stuff they understand / are best to the detriment of where the actual focus needs to be. In a lot of cases, this is despite the insistence of the supposed non-expert who is the one suffering as a result.
Some of the worst cases are as a child, where you get in trouble twice. First for wasting adults time because you didn't tell them properly, and then again for pointing out that you did.
Elderly relatives writhing in pain, only to have doctors say it's indigestion (it was a perforated ulcer and an uncle had previously died from a wrongly diagnosed ulcer perforating). My partner was misdiagnosed with flu when it was pneumonia which then developed into pleurisy (I'd never seen either of the latter, but was telling the doctor that's what the symptoms looked like - 15 years later he still suffers pain from the pleurisy). I had an arm paralyzed through severe pain and the consultant doctor planned an operation "to cut the nerve" - I said I thought it was a frozen shoulder and that such a procedure was unnecessary; 6 months later the paralysis began to subside and the consultant agreed it was a frozen shoulder). Another relative died of bowel cancer that was said to be back pain (she died in the hospital where she worked). I know of several people who were telling the doctor they had cancer, only to have the doctors dismiss it as trivial, with most of these people dying because of their untreated cancer. As a child I had joint pains for years that were diagnosed as "growing pains" but turned out to a hip disease (younger cousins ended up with the same condition and because I'd already had it, they were more readily diagnosed by family members).
In both directions (treating trivial as serious and treating serious as trivial) I've seen so many mistakes. I'd be much happier to see a doctor google the symptoms rather than jump to a conclusion about what is wrong.
There's a famous anecdote where junior doctors are taught the importance of observation, by senior doctors tricking them into tasting urine. It doesn't seem to be a lesson they learn. Even when their own objective test results are contra-indicative of their pre-judgement I've seen doctors scratch their heads but stick with their incorrect pre-judgement.
When doctors I know have a family member go into hospital, you should see how attentive my doctor friends get concerning what is being said and done to their relatives. Some doctors will not even allow relatives to go into hospital for non-emergency treatment at certain times of year (because of timetabling there can be very inexperienced doctors on duty at certain times of the year).
As someone who suffered through that on _both_ shoulders I can sympathize. For me, the doctor missed it. The chiropractor I was sent to, took one look and said it was 'frozen shoulder'. I have never even heard of such a thing before. It took nearly two years to get full movement on my right shoulder. Then the left froze :-(
I'm just curious. Are these experiences in the UK?
I have seen and heard of some similar things, but my experience is only with the US healthcare system.
If I’d been in the patch submitter’s shoes, I wouldn’t have thought twice about writing off that community.
If I had gotten your reply, instead: 100% fair play, thank you for your consideration, and send my love to the dev team.
Messaging matters.
Honestly, if someone's spending time working on a high value open source project (which PG absolutely is), I'd rather they spend less time (than I do) crafting their internet comments to sound nice and more time contributing to society. And I hope people who actually use the product feel the same way, understand why every single use case can't be carefully considered every time it comes up, and don't take it personally.
People like to think they can escape politics. They can’t. Any group of >1 humans will involve politics.
Learning how to be respectful and polite is like learning how to touch type: it’s a small, painful price to pay once, for a lifetime of copious reward.
Except georgebarnett and jarym.
Or perhaps that was the point, that PostgreSQL isn’t doing much! :)
> Actually as great as Postgres is and as generally approachable the community is - my experience was the same a few times and I read it on the mailing list happening to others: - jarym
It seems that despite things not being perfect (and they never are), these people are still having positive experiences with the product and the community overall. So, to restate, some people care enough to post about it on HN, but nobody (who continues to use PG, and there are a lot of us) cares all that much.
Linus was trying to make things work, with profanity. Postgres couldn't be bothered.
Sure, performative profanity isn't everyone's cup of tea, but milquetoast passive-aggressive dismissals of people like OP who ARE TOTALLY RIGHT aren't actually nice.
It's ten years too soon to conclude that Torvalds backing away from abrasive behaviour didn't kill Linux.
That said, I feel that a strong and positive community around a project is always an asset. I’ve seen many more projects fail due to community interaction being bad than I have from it being good.
The patch author does the "initial" work. But then it's up to the team to learn the patch, understand it and keep maintaining it.
Every line of code is baggage.
If there is no demand for something at the time, it makes sense for maintainers to reject that. It's up to them to maintain that patch from now on.
No one is asking them to. An open source project is not a corporation, it has no shareholders who require growth at all costs. So someone doesn't contribute to the project, if there's enough other contributors to keep it healthy then who care? No need to try and get every single potential contributor to contribute code to the project.
It's not hard.
A second, separate thought. Perhaps it's not quite as easy as you think it is, and perhaps you're not as good at it as you think you are. Case in point, the comment you just made was not exactly the nicest I've read today.
- technical: E-mail is not a particularly good medium to convey emotions (in either way). For example someone with a naturally terse communication style may be perceived as harsh, while in person he's actually a very friendly bloke. And there's no way to communicate this impression back.
- cultural: Often what is quite polite in one culture may be seen as quite impolite or even rude in another. It's not just country vs. country, but even region vs. region (like for example East Coast vs. West Coast).
- personal: People in the community may know each other pretty well, in which case the communication style may be quite a bit more direct. But others may lack the context.
It's almost impossible to get it right all the time, without resorting to entirely mechanical corporate communication style. Which is not fut at all.
Of course, this does not mean there are no truly harsh / rude / WTF posts (even on PostgreSQL lists). But I'd say most of the time it's not meant that way.
> Another example: NAMEDATALEN restricts every identifier to 63 bytes - a limit that causes frequent issues (more so now that we have partitioning) and also a problem for multi-lingual table names. It’s been proposed to increase this limit a few times. Every time the answer has been: abbreviate your table names or recompile your own version of Postgres.
I think if it were easy, it'd immediately be fixed, but there's a fair bit of complexity in fixing it nicely. For partially historical and partially good reasons object names are allocated with NAMEDATALEN space, even for shorter names. So just increasing it would further waste memory... We're going to have to fix this properly one of these days.
Agreeing that there is something worthy of fixing is a first step. It should have happened with this NFS patch and imo some other stuff. The considerations for how and when should be dear with separately.
But there were like multiple people agreeing that it needs to be changed. Including the first two responses that the thread got. And there were legitimate questions around how interrupts need to be handled, about errors ought to be signaled if writes partially succeed and everything. Do you really expect us to integrate patches without thinking about that? And then the author vanished...
Whoa! You made huge leap there. At what point was it suggested that patches be recklessly applied?
That didn't happen. Your quote actually suggests a reasonable progression and at no point is there any suggestion, implied or otherwise, that changes be integrated without due consideration.
Not irrationally dismissing criticism != abandoning sound design and development.
That's not how well run projects function.
Which is why people are not enthusiastic about changing it, when there are fairly simple workarounds (assuming keeping the names short is considered to be a workaround).
Very likely many years, or even never. People don't use large names because they like it, they always prefer small ones.
How much memory are we talking about?
Well, we don't have exactly a barrage of complaints about the current limit either.
> How much memory are we talking about?
Good question.
The thing is - it's not just about table names. NameData is used for any object name, so it affects pretty much any system catalog storing name. A simple grep on the repo says it affects about 40 catalogs (out of 80), including pg_attribute, pg_class, pg_operator, pg_proc, pg_type (which tend to be fairly large).
So the amount of additional memory may be quite significant, because all of this is cached in various places.
The impact of doubling NameData size would be quite a bit worse, though, thanks to doubling of chunk-size in allocset. At the moment it fits into a 128B chunk (so just ~16B wasted), but by doubling NameData to 128B the struct would suddenly be 176B, which requires 256B chunk (so 80B wasted). Yuck.
Well, but on-disk varlena data is included. pg_column_size() averages 144 bytes for pg_attribute on my system.
> The impact of doubling NameData size would be quite a bit worse, though, thanks to doubling of chunk-size in allocset. At the moment it fits into a 128B chunk (so just ~16B wasted), but by doubling NameData to 128B the struct would suddenly be 176B, which requires 256B chunk (so 80B wasted). Yuck.
I'm not sure that actually matters that much. Most attributes are allocated as part of TupleDescData, but that allocates all attributes together.
Sure, but I thought we're talking about in-memory stuff as you've been talking about tuple descriptors. I don't think the on-disk size matters all that much, TBH, it's likely just a tiny fraction of data stored in the cluster.
> I'm not sure that actually matters that much. Most attributes are allocated as part of TupleDescData, but that allocates all attributes together.
Ah. Good point.
I've seen pg_attribute take up very significant fractions of the database numerous times, so I do think the on-disk size can matter. And there's plenty places, e.g. catcache, where we store the full on-disk tuple (rather than just the fixed-length prefix); so the on-disk size is actually quite relevant for the in-memory bit too.
not just bias against change. while there are some very talented and friendly people in the pg community, there are a few bad actors that are openly hostile and aggressive, that feel that they must be part of every discussion. it gets worse when it is a change that they made that is causing an issue, as ego takes a front seat.
unfortunately, these few bad actors make dealing with the pg mailing lists in general very unpleasant, and have made myself (a popular extension maintainer) and others try to keep interaction to an absolute minimum. that's not good for the community.
I'm sure there were cases of inappropriate / rude communication, but AFAICS those were rare one-off incidents. While you're apparently talking about long-term and consistent behavior. So I wonder who you're talking about? I can't think of anyone who'd consistently behave like that - particularly not among senior community members.
my comment, which is based on the multiple interactions I've had with the community, stands as is: some fantastic people, and a few aggressive bad actors that spoil things.
(Putting tenant_id as a column was not an option because for each tenant, a third-party software was started that wanted to have its own DB.)
This is not unique to Postgres. I've seen this behavior on many development mailing lists (e.g. Mutt-dev).
The core team has also to prioritize, deal with already planned features, and shoot down tons of people with inane ideas as well (not just good ones).
After reading this, I have been wondering if the other requests/ideas are not startup ideas
If you look at https://wiki.postgresql.org/wiki/PostgreSQL_derived_database..., it's a pretty long list - some of the product are successful, some are dead. And then there are products adding some extra sauce on top of PostgreSQL (e.g. timescaleDB).
There's literally one person saying that NFS is crapshot anyway, and several +1s for retries. And the former was accompanied with several questions about the concrete implementation.
Many others were as you note bikeshedding the commit.
Only one, if I recall, questioned why it was a controversial patch at all.
If you check the patch that was committed eventually, IIRC it’s identical to what I proposed.
As I said, I don’t look back particularly favourably on my interactions with the community.
It seems like a fairly good example of an engineering discussion. Even if the patch is correct and conforming and solves a problem, that doesn't mean there is no use for further discussion, and the surrounding discussion does seem to have merit.
Things like:
* Are there closely-related problems still left unsolved (e.g. retrying reads)?
* Is something not configured according to best practices known by other community members?
* Expressing an opinion that the use case is dangerous, so that nobody (including other people reading the thread in the future) will take it as an endorsement for running postgres on NFS.
* Some legitimate-sounding questions about the specifics of the patch (around zero returns, what writeAll handles versus its callers, etc.).
* At least one person agreed with you that it's a reasonable thing to do.
I don't think HN is really the right place to assess the technical merits of a postgres patch, but the discussion itself seems well within reasonable bounds.
Thinking about the social structure for a minute, I honestly think you might have done better to leave out some of the content of your patch submission, let people push back on the more obvious stuff, and have ready answers. There's a phenomena where curators feel they must push back, and they feel weird when there's nothing to criticize - you can get around this by giving them something to criticize, with a ready-at-hand response!
Sorry this happened.
> The artist working on the queen animations for Battle Chess... did the animations for the queen the way that he felt would be best, with one addition: he gave the queen a pet duck. He animated this duck through all of the queen’s animations, had it flapping around the corners. He also took great care to make sure that it never overlapped the “actual” animation.
> As expected, he was asked to remove the duck, which he did, without altering the real Queen animation.
In fact in open source I can imagine a strategy to get an underhanded bug accepted by pairing it with an obvious, trivial bug. The obvious one gets caught and submitter apologizes and resubmits. Then the dev merges the underhanded bug, comforted that a fairly common iteration cycle has been completed with a newbie.
One of the interesting points I’ve relfected on over time has been how _my_ issue was solved with the patch, however for others it wasn’t.
When I think about this I of course recognise that Postgres owes me nothing, however we both had similarly aligned objectives (fix bugs, do good), but because of our inability to successfully communicate, we didn’t get to a productive outcome and so a fixable bug sat in the release for some time.
I do wonder how we go about improving that kind of circumstance.
In Morgan LLywelyn's Finn Mac Cool ( https://www.amazon.com/dp/0312877374/ ), Finn is a man with no family from an inferior tribe, and he's a troop leader in a band of scummy soldiers of no social standing whatever. On the other hand, his potential is obvious -- he will eventually work his way up to self-made king.
While stationed in the capital, he falls in love with a respectable, middle-class blacksmith's daughter. She won't give him the time of day because of the difference in social class, but over time, as his respectability steadily climbs, she warms up to him.
They have a failed sexual encounter, and everything falls apart. She feels too awkward to approach him anymore. He believes (incorrectly) that they've become married at a level inappropriate to her class, and eventually comes to her home to propose a much higher grade of marriage. But she doesn't know how to accept without -- in her own eyes -- suffering a loss of dignity. A painful scene follows in which it's obvious that he wants to marry her, she wants to marry him, her mother wants her to marry him, but somehow none of them can see how to actually get to that point.
People really don't go for innovation in social protocols, even when the protocols they know are failing them.
So you suggest that the patches should be obviously “worse” in order to have better chance to be accepted?
IMHO it's a bit strange to assume everyone will agree with your patch from the very beginning. People may lack proper understanding of the issue, or they may see it from a different angle, and so on. Convincing others that your solution is the right one is an important part of getting patch done. I don't see anything wrong with that.
> 2. What is the rationale for supposing that a retry a nanosecond later will help? If it will help, why didn't the kernel just do that?
https://www.postgresql.org/message-id/223BF4DE-B274-4428-832...
The "asshole reviewer" is definitely a thing.
I've only submitted one patch (\pset linestyle unicode for psql), and with a few rounds of review and revision it made it in. Overall I found this process nitpicky but productive. However, there is a point at which the harshly critical review can be detrimental, and from the other comments mentioned here, it sounds like this has been the case in the past.
With regard to the semantics of write(2) and fwrite(3) these are clearly documented in SUS and other standards, and the "valid disagreement" in this case may have been very counter-productive if it killed off proper review and acceptance of a genuine bug. There are, of course, problems with fsync(2) which have had widespread discussion for years.
Can you share an example of a review that you consider harsh? (feel free to share privately, I'm simply interested in what you consider harsh)
I admit some of the reviews may be a bit more direct, particularly between senior hackers who know each other, and from time to time there are arguments. It's not just rainbows and unicorns all the time, but in general I find the discussion extremely civilized (particularly for submissions from new contributors). But maybe that's just survivor bias, and the experience is much worse for others ...
> I've only submitted one patch (\pset linestyle unicode for psql), and with a few rounds of review and revision it made it in. Overall I found this process nitpicky but productive. However, there is a point at which the harshly critical review can be detrimental, and from the other comments mentioned here, it sounds like this has been the case in the past.
Oh, 2009 - good old days ;-) Thanks for the patch, BTW.
There's a fine line between nitpicking and attention to detail. We do want to accept patches, but OTOH we don't want to make the code worse (not just by introducing bugs, even code style matters too). At some point the committer may decide the patch is in "good enough" shape and polish it before the commit, but most of that should happen during the review.
> Can you share an example of a review that you consider harsh? (feel free to share privately, I'm simply interested in what you consider harsh)
I wouldn't use the word harsh, but I do think there's plenty reviews where too much bikeshedding happens.
What the hell is wrong with people?
With a lot of people you will never need this. But especially in larger projects where any number of people might latch on and review submissions, the chances for someone to find something to complain about goes up rapidly.
And when one person has found something to complain about, all kinds of other social dysfunction quickly becomes an issue too.
In most corporate projects, odds are you're dealing with a much smaller pool of reviewers.
It's a pity a lot developers out there do not have an ingrained awareness about this.
> 2011-07-31 22:13:35 EST postgres postgres [local] LOG: connection authorized: user=postgres database=postgres
> 2011-07-31 22:13:35 EST ERROR: could not write block 1 of relation global/2671: wrote only 4096 of 8192 bytes
> 2011-07-31 22:13:35 EST HINT: Check free disk space.
> 2011-07-31 22:13:35 EST CONTEXT: writing block 1 of relation global/2671
> 2011-07-31 22:13:35 EST [unknown] [unknown] LOG: connection received: host=[local]
The proposed patch retries rather than throwing an error.
http://habitatchronicles.com/2004/04/you-cant-tell-people-an...
If you can just give us the anecdote rather than making a vague, sweeping critique of MS OSS projects, you might avoid the downvotes.
I've given up on both :/
I patched my own systems (wrap the calls in a loop as per standard practice) and then proceeded to run literally hundreds of thousands of PostgreSQL instances on NFS for many more years with no problems.
The patch was eventually integrated it seems but I never found out why because I lost interest in trying to work with the community after that experience.