Обсуждение: Re: [HACKERS] Replication documentation addition
Dawid Kuroczko wrote: > Bruce, I've read Your documentation and I was left a bit with a feeling > that it's a bit too generic. It's almost as if it could be about just about > any major database, not PostgreSQL specific. I feel that, when I'm > reading PostgreSQL docs I would like to know how to set up multi-master > replication with PostgreSQL not an explanation what a multi-master > replication is. It's not about the actual documentation content, but rather > on accents distribution. Now it is something like: "These are the types > of replication solutions possible, some of them can be done with PostgreSQL", > I think it should be rather: "With PostgreSQL and some third-party tools you > can achieve such and such replication solutions, oh and by the way, research > is done on such and such replication method, but it's not a production quality > yet". > > And I try to think as my DBA-mates would do if they read the documentation, > I'm not sure they would end up enlighted after reading the docs -- thay would > probably say: "hey, I knew that, it's well structured there, but I > still don't know > what should I use", or maybe "where can I read something about this slony > thing anyway?". Well, the idea is to have a web site that lists all the solutions that can be updated regularly, perhaps using the categories from the documentation. -- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
On Wed, Oct 25, 2006 at 04:42:17PM -0400, Bruce Momjian wrote: > Dawid Kuroczko wrote: > > Bruce, I've read Your documentation and I was left a bit with a feeling > > that it's a bit too generic. It's almost as if it could be about just about > > any major database, not PostgreSQL specific. I feel that, when I'm > > reading PostgreSQL docs I would like to know how to set up multi-master > > replication with PostgreSQL not an explanation what a multi-master > > replication is. It's not about the actual documentation content, but rather > > on accents distribution. Now it is something like: "These are the types > > of replication solutions possible, some of them can be done with PostgreSQL", > > I think it should be rather: "With PostgreSQL and some third-party tools you > > can achieve such and such replication solutions, oh and by the way, research > > is done on such and such replication method, but it's not a production quality > > yet". > > > > And I try to think as my DBA-mates would do if they read the documentation, > > I'm not sure they would end up enlighted after reading the docs -- thay would > > probably say: "hey, I knew that, it's well structured there, but I > > still don't know > > what should I use", or maybe "where can I read something about this slony > > thing anyway?". > > Well, the idea is to have a web site that lists all the solutions that > can be updated regularly, perhaps using the categories from the > documentation. And the docs should point to that page, prominently (presumably that will happen after the page actually exists). Something else worth doing though is to have a paragraph explaining why there's no built-in replication. I don't have time to write something right now, but I can do it later tonight if no one beats me to it. -- Jim Nasby jim@nasby.net EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Jim C. Nasby wrote: > Something else worth doing though is to have a paragraph explaining why > there's no built-in replication. I don't have time to write something > right now, but I can do it later tonight if no one beats me to it. I thought that was implied in the early paragraph about why there are many solutions. -- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
On Wed, Oct 25, 2006 at 08:42:07PM -0400, Bruce Momjian wrote: > Jim C. Nasby wrote: > > Something else worth doing though is to have a paragraph explaining why > > there's no built-in replication. I don't have time to write something > > right now, but I can do it later tonight if no one beats me to it. > > I thought that was implied in the early paragraph about why there are > many solutions. I think we should explicitely spell it out, especially considering how many times people ask about it. How about... This multitude of choices is why PostgreSQL does not ship with a replication solution by default; any bundled solution would only satisfy a subset of replication needs. (sorry for the non-standard patch, but anoncvs isn't sync'd up yet). -- Jim Nasby jim@nasby.net EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Вложения
Jim C. Nasby wrote: > On Wed, Oct 25, 2006 at 08:42:07PM -0400, Bruce Momjian wrote: > > Jim C. Nasby wrote: > > > Something else worth doing though is to have a paragraph explaining why > > > there's no built-in replication. I don't have time to write something > > > right now, but I can do it later tonight if no one beats me to it. > > > > I thought that was implied in the early paragraph about why there are > > many solutions. > > I think we should explicitely spell it out, especially considering how > many times people ask about it. How about... > > This multitude of choices is why PostgreSQL does not ship with a > replication solution by default; any bundled solution would only > satisfy a subset of replication needs. The problem is that we do have some solutions in our code, like doing data partitioning in the application, warm standby, or using a shared disk for failover, so how do we spell that out? I say there are multiple solutions, but I don't see how I can say that all are external and not included. -- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
Bruce Momjian wrote:
> Jim C. Nasby wrote:
>> On Wed, Oct 25, 2006 at 08:42:07PM -0400, Bruce Momjian wrote:
>>> Jim C. Nasby wrote:
>>>> Something else worth doing though is to have a paragraph explaining why
>>>> there's no built-in replication. I don't have time to write something
>>>> right now, but I can do it later tonight if no one beats me to it.
>>> I thought that was implied in the early paragraph about why there are
>>> many solutions.
>> I think we should explicitely spell it out, especially considering how
>> many times people ask about it. How about...
>>
>> This multitude of choices is why PostgreSQL does not ship with a
>> replication solution by default; any bundled solution would only
>> satisfy a subset of replication needs.
>
> The problem is that we do have some solutions in our code, like doing
> data partitioning in the application, warm standby, or using a shared
> disk for failover, so how do we spell that out? I say there are
> multiple solutions, but I don't see how I can say that all are external
> and not included.
None of those are replication solutions. So I would have to agree with
Jim here.
This isn't about what people do with their app, so that is not relevant.
Warm standby is PITR which is a backup and recovery solution. It does
not include a failover solution and is *not* replication. It technically
does not provide an HA solution either as it will be almost always
farther behind than a replication solution.
Shared disk for failover could be used by anything it isn't special to a
replication scenario it is standard for many HA.
Sincerely,
Joshua D. Drake
--
=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/
Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate
Joshua D. Drake wrote: > Bruce Momjian wrote: > > Jim C. Nasby wrote: > >> On Wed, Oct 25, 2006 at 08:42:07PM -0400, Bruce Momjian wrote: > >>> Jim C. Nasby wrote: > >>>> Something else worth doing though is to have a paragraph explaining why > >>>> there's no built-in replication. I don't have time to write something > >>>> right now, but I can do it later tonight if no one beats me to it. > >>> I thought that was implied in the early paragraph about why there are > >>> many solutions. > >> I think we should explicitely spell it out, especially considering how > >> many times people ask about it. How about... > >> > >> This multitude of choices is why PostgreSQL does not ship with a > >> replication solution by default; any bundled solution would only > >> satisfy a subset of replication needs. > > > > The problem is that we do have some solutions in our code, like doing > > data partitioning in the application, warm standby, or using a shared > > disk for failover, so how do we spell that out? I say there are > > multiple solutions, but I don't see how I can say that all are external > > and not included. > > None of those are replication solutions. So I would have to agree with > Jim here. > > This isn't about what people do with their app, so that is not relevant. > > Warm standby is PITR which is a backup and recovery solution. It does > not include a failover solution and is *not* replication. It technically > does not provide an HA solution either as it will be almost always > farther behind than a replication solution. > > Shared disk for failover could be used by anything it isn't special to a > replication scenario it is standard for many HA. The section is no longer titled only "replication", but is now "Failover, Replication, Load Balancing, and Clustering Options", so it is more a catch-all, and hence saying nothing is included doesn't make sense. You could say no "replication" is included, but replication is only one part of the section, so where do you put that, and why is it worth it? -- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
On Thu, Oct 26, 2006 at 11:59:57AM -0400, Bruce Momjian wrote: > Jim C. Nasby wrote: > > On Wed, Oct 25, 2006 at 08:42:07PM -0400, Bruce Momjian wrote: > > > Jim C. Nasby wrote: > > > > Something else worth doing though is to have a paragraph explaining why > > > > there's no built-in replication. I don't have time to write something > > > > right now, but I can do it later tonight if no one beats me to it. > > > > > > I thought that was implied in the early paragraph about why there are > > > many solutions. > > > > I think we should explicitely spell it out, especially considering how > > many times people ask about it. How about... > > > > This multitude of choices is why PostgreSQL does not ship with a > > replication solution by default; any bundled solution would only > > satisfy a subset of replication needs. > > The problem is that we do have some solutions in our code, like doing > data partitioning in the application, warm standby, or using a shared > disk for failover, so how do we spell that out? I say there are > multiple solutions, but I don't see how I can say that all are external > and not included. Good point... how about this? -- Jim Nasby jim@nasby.net EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Вложения
Jim C. Nasby wrote: > On Thu, Oct 26, 2006 at 11:59:57AM -0400, Bruce Momjian wrote: > > Jim C. Nasby wrote: > > > On Wed, Oct 25, 2006 at 08:42:07PM -0400, Bruce Momjian wrote: > > > > Jim C. Nasby wrote: > > > > > Something else worth doing though is to have a paragraph explaining why > > > > > there's no built-in replication. I don't have time to write something > > > > > right now, but I can do it later tonight if no one beats me to it. > > > > > > > > I thought that was implied in the early paragraph about why there are > > > > many solutions. > > > > > > I think we should explicitely spell it out, especially considering how > > > many times people ask about it. How about... > > > > > > This multitude of choices is why PostgreSQL does not ship with a > > > replication solution by default; any bundled solution would only > > > satisfy a subset of replication needs. > > > > The problem is that we do have some solutions in our code, like doing > > data partitioning in the application, warm standby, or using a shared > > disk for failover, so how do we spell that out? I say there are > > multiple solutions, but I don't see how I can say that all are external > > and not included. > > Good point... how about this? Sorry, that is too preachy, and I have the extensibility issue addressed in the commerical solutions section. -- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +