Thread: Hstore: Query speedups with Gin index
Hey everyone,
I'm looking for feedback on a contrib/hstore patch.
We've been experiencing slow "@>" queries involving an hstore column that's covered by a Gin index. At the current postgresql git HEAD, the hstore <-> gin interface produces the following text items to be indexed:
hstore: "'a'=>'1234', 'b'=>'test'"
Produces indexed text items: "Ka", "V1234", "Kb", "Vtest"
For the size of our production table (10s of millions of rows), I observed significant query speedups by changing the index strategy to the following:
hstore: "'a'=>'1234', 'b'=>'test'"
Produces indexed text items: "Ka", "KaV1234", "Kb", "KbVtest"
The combined entry is used to support "contains (@>)" queries, and the key only item is used to support "key contains (?)" queries. This change seems to help especially with hstore keys that have high cardinalities. Downsides of this change is that it requires an index rebuild, and the index will be larger in size.
Patch attached. Any thoughts on this change?
Thanks,
Blake
Attachment
On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote: > We've been experiencing slow "@>" queries involving an hstore column that's > covered by a Gin index. At the current postgresql git HEAD, the hstore <-> > gin interface produces the following text items to be indexed: > > hstore: "'a'=>'1234', 'b'=>'test'" > Produces indexed text items: "Ka", "V1234", "Kb", "Vtest" > > For the size of our production table (10s of millions of rows), I observed > significant query speedups by changing the index strategy to the following: What is the order of the speedup? > hstore: "'a'=>'1234', 'b'=>'test'" > Produces indexed text items: "Ka", "KaV1234", "Kb", "KbVtest" I am not a gin expert, but do you see the same speedup for tables with a lower number of rows, or even a degradation in performance? > The combined entry is used to support "contains (@>)" queries, and the key > only item is used to support "key contains (?)" queries. This change seems > to help especially with hstore keys that have high cardinalities. Downsides > of this change is that it requires an index rebuild, and the index will be > larger in size. Index rebuild would be a problem only for minor releases, this patch would be applied only on the current master branch for 9.4 and above. > Patch attached. Any thoughts on this change? Please add your patch to the next commit fest that will begin in 3 weeks so as you could get more formal review. https://commitfest.postgresql.org/action/commitfest_view?id=19 Regards, -- Michael
Michael Paquier <michael.paquier@gmail.com> writes: > On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote: >> The combined entry is used to support "contains (@>)" queries, and the key >> only item is used to support "key contains (?)" queries. This change seems >> to help especially with hstore keys that have high cardinalities. Downsides >> of this change is that it requires an index rebuild, and the index will be >> larger in size. > Index rebuild would be a problem only for minor releases, That's completely false; people have expected major releases to be on-disk-compatible for several years now. While there probably will be future releases in which we are willing to break storage compatibility, a contrib module doesn't get to dictate that. What might be a practical solution, especially if this isn't always a win (which seems likely given the index-bloat risk), is to make hstore offer two different GIN index opclasses, one that works the traditional way and one that works this way. Another thing that needs to be taken into account here is Oleg and Teodor's in-progress work on extending hstore: https://www.pgcon.org/2013/schedule/events/518.en.html I'm not sure if this patch would conflict with that at all, but it needs to be considered. regards, tom lane
Michael, take a look on http://obartunov.livejournal.com/171959.html
As for the indexing stuff we already thought many times about key&value mixing, but real solution, probably, could come from spgist and gin combination. I mean, spgist (suffix array) instead of btree for avoiding key duplication, which is real stopper for key.value mixing, especially, for deep nesting structures. We'll research further and probably will develop a prototype of such hybrid search tree.
On Mon, Aug 26, 2013 at 6:11 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Michael Paquier <michael.paquier@gmail.com> writes:
> On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote:>> The combined entry is used to support "contains (@>)" queries, and the keyThat's completely false; people have expected major releases to be
>> only item is used to support "key contains (?)" queries. This change seems
>> to help especially with hstore keys that have high cardinalities. Downsides
>> of this change is that it requires an index rebuild, and the index will be
>> larger in size.
> Index rebuild would be a problem only for minor releases,
on-disk-compatible for several years now. While there probably will be
future releases in which we are willing to break storage compatibility,
a contrib module doesn't get to dictate that.
What might be a practical solution, especially if this isn't always a
win (which seems likely given the index-bloat risk), is to make hstore
offer two different GIN index opclasses, one that works the traditional
way and one that works this way.
Another thing that needs to be taken into account here is Oleg and
Teodor's in-progress work on extending hstore:
https://www.pgcon.org/2013/schedule/events/518.en.html
I'm not sure if this patch would conflict with that at all, but it
needs to be considered.
regards, tom lane
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On Sun, Aug 25, 2013 at 10:11:50PM -0400, Tom Lane wrote: > Michael Paquier <michael.paquier@gmail.com> writes: > > On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote: > >> The combined entry is used to support "contains (@>)" queries, and the key > >> only item is used to support "key contains (?)" queries. This change seems > >> to help especially with hstore keys that have high cardinalities. Downsides > >> of this change is that it requires an index rebuild, and the index will be > >> larger in size. > > > Index rebuild would be a problem only for minor releases, > > That's completely false; people have expected major releases to be > on-disk-compatible for several years now. While there probably will be > future releases in which we are willing to break storage compatibility, > a contrib module doesn't get to dictate that. > > What might be a practical solution, especially if this isn't always a > win (which seems likely given the index-bloat risk), is to make hstore > offer two different GIN index opclasses, one that works the traditional > way and one that works this way. > > Another thing that needs to be taken into account here is Oleg and > Teodor's in-progress work on extending hstore: > https://www.pgcon.org/2013/schedule/events/518.en.html > I'm not sure if this patch would conflict with that at all, but it > needs to be considered. We can disallow in-place upgrades for clusters that use certain contrib modules --- we have done that in the past. -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. +
On 2013-08-28 13:31:22 -0400, Bruce Momjian wrote: > On Sun, Aug 25, 2013 at 10:11:50PM -0400, Tom Lane wrote: > > Michael Paquier <michael.paquier@gmail.com> writes: > > > On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote: > > >> The combined entry is used to support "contains (@>)" queries, and the key > > >> only item is used to support "key contains (?)" queries. This change seems > > >> to help especially with hstore keys that have high cardinalities. Downsides > > >> of this change is that it requires an index rebuild, and the index will be > > >> larger in size. > > > > > Index rebuild would be a problem only for minor releases, > > > > That's completely false; people have expected major releases to be > > on-disk-compatible for several years now. While there probably will be > > future releases in which we are willing to break storage compatibility, > > a contrib module doesn't get to dictate that. > > > > What might be a practical solution, especially if this isn't always a > > win (which seems likely given the index-bloat risk), is to make hstore > > offer two different GIN index opclasses, one that works the traditional > > way and one that works this way. > > > > Another thing that needs to be taken into account here is Oleg and > > Teodor's in-progress work on extending hstore: > > https://www.pgcon.org/2013/schedule/events/518.en.html > > I'm not sure if this patch would conflict with that at all, but it > > needs to be considered. > > We can disallow in-place upgrades for clusters that use certain contrib > modules --- we have done that in the past. But that really cannot be acceptable for hstore. The probably most widely used extension there is. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services
Thanks for the feedback everyone. I've attached the patch that we are now running in production to service our hstore include queries. We rebuilt the index to account for the on-disk incompatibility. I've submitted the patch to commitfest here: https://commitfest.postgresql.org/action/patch_view?id=1203
Michael: I don't have a formal benchmark, but several of our worst queries went from 10-20 seconds per query down to 50-400 ms. These are numbers we've seen when testing real production queries against our production dataset with real world access patterns.
Oleg: Thanks for your thoughts on this change. As for the spgist / gin work you're doing, is there anything you need help with or are you still in the research phase? I'd love to help get something more robust merged into mainline if you think there's collaborative work to be done (even if it's only user testing).
Thanks,
Blake
On Wed, Aug 28, 2013 at 12:40 PM, Andres Freund <andres@2ndquadrant.com> wrote:
But that really cannot be acceptable for hstore. The probably mostOn 2013-08-28 13:31:22 -0400, Bruce Momjian wrote:
> On Sun, Aug 25, 2013 at 10:11:50PM -0400, Tom Lane wrote:
> > Michael Paquier <michael.paquier@gmail.com> writes:
> > > On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote:
> > >> The combined entry is used to support "contains (@>)" queries, and the key
> > >> only item is used to support "key contains (?)" queries. This change seems
> > >> to help especially with hstore keys that have high cardinalities. Downsides
> > >> of this change is that it requires an index rebuild, and the index will be
> > >> larger in size.
> >
> > > Index rebuild would be a problem only for minor releases,
> >
> > That's completely false; people have expected major releases to be
> > on-disk-compatible for several years now. While there probably will be
> > future releases in which we are willing to break storage compatibility,
> > a contrib module doesn't get to dictate that.
> >
> > What might be a practical solution, especially if this isn't always a
> > win (which seems likely given the index-bloat risk), is to make hstore
> > offer two different GIN index opclasses, one that works the traditional
> > way and one that works this way.
> >
> > Another thing that needs to be taken into account here is Oleg and
> > Teodor's in-progress work on extending hstore:
> > https://www.pgcon.org/2013/schedule/events/518.en.html
> > I'm not sure if this patch would conflict with that at all, but it
> > needs to be considered.
>
> We can disallow in-place upgrades for clusters that use certain contrib
> modules --- we have done that in the past.
widely used extension there is.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
Blake Smith
http://blakesmith.me
@blakesmith
Attachment
On Tue, 2013-09-03 at 09:24 -0500, Blake Smith wrote: > Thanks for the feedback everyone. I've attached the patch that we are > now running in production to service our hstore include queries. We > rebuilt the index to account for the on-disk incompatibility. I've > submitted the patch to commitfest > here: https://commitfest.postgresql.org/action/patch_view?id=1203 I'm getting the attached failure from the hstore regression test.
Attachment
Hi Peter,
Thanks for checking the tests. I wasn't able to duplicate your test results. Did you run the hstore regression tests with the revised patch I attached in the thread? Attached is the output I got with the latest patch applied.
Thanks!
Blake
On Tue, Sep 3, 2013 at 8:04 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
On Tue, 2013-09-03 at 09:24 -0500, Blake Smith wrote:I'm getting the attached failure from the hstore regression test.
> Thanks for the feedback everyone. I've attached the patch that we are
> now running in production to service our hstore include queries. We
> rebuilt the index to account for the on-disk incompatibility. I've
> submitted the patch to commitfest
> here: https://commitfest.postgresql.org/action/patch_view?id=1203
Blake Smith
http://blakesmith.me
@blakesmith
Attachment
Blake,
I think it's better to implement this patch as a separate opclass, so users will have option to choose indexing.On Tue, Sep 3, 2013 at 6:24 PM, Blake Smith <blakesmith0@gmail.com> wrote:
Thanks for the feedback everyone. I've attached the patch that we are now running in production to service our hstore include queries. We rebuilt the index to account for the on-disk incompatibility. I've submitted the patch to commitfest here: https://commitfest.postgresql.org/action/patch_view?id=1203Michael: I don't have a formal benchmark, but several of our worst queries went from 10-20 seconds per query down to 50-400 ms. These are numbers we've seen when testing real production queries against our production dataset with real world access patterns.Oleg: Thanks for your thoughts on this change. As for the spgist / gin work you're doing, is there anything you need help with or are you still in the research phase? I'd love to help get something more robust merged into mainline if you think there's collaborative work to be done (even if it's only user testing).Thanks,BlakeBlake SmithOn Wed, Aug 28, 2013 at 12:40 PM, Andres Freund <andres@2ndquadrant.com> wrote:But that really cannot be acceptable for hstore. The probably mostOn 2013-08-28 13:31:22 -0400, Bruce Momjian wrote:
> On Sun, Aug 25, 2013 at 10:11:50PM -0400, Tom Lane wrote:
> > Michael Paquier <michael.paquier@gmail.com> writes:
> > > On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote:
> > >> The combined entry is used to support "contains (@>)" queries, and the key
> > >> only item is used to support "key contains (?)" queries. This change seems
> > >> to help especially with hstore keys that have high cardinalities. Downsides
> > >> of this change is that it requires an index rebuild, and the index will be
> > >> larger in size.
> >
> > > Index rebuild would be a problem only for minor releases,
> >
> > That's completely false; people have expected major releases to be
> > on-disk-compatible for several years now. While there probably will be
> > future releases in which we are willing to break storage compatibility,
> > a contrib module doesn't get to dictate that.
> >
> > What might be a practical solution, especially if this isn't always a
> > win (which seems likely given the index-bloat risk), is to make hstore
> > offer two different GIN index opclasses, one that works the traditional
> > way and one that works this way.
> >
> > Another thing that needs to be taken into account here is Oleg and
> > Teodor's in-progress work on extending hstore:
> > https://www.pgcon.org/2013/schedule/events/518.en.html
> > I'm not sure if this patch would conflict with that at all, but it
> > needs to be considered.
>
> We can disallow in-place upgrades for clusters that use certain contrib
> modules --- we have done that in the past.
widely used extension there is.
Greetings,
Andres Freund
--
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PostgreSQL Development, 24x7 Support, Training & Services--
http://blakesmith.me@blakesmith
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On 9/5/13 2:42 PM, Blake Smith wrote: > Thanks for checking the tests. I wasn't able to duplicate your test > results. Did you run the hstore regression tests with the revised patch > I attached in the thread? Attached is the output I got with the latest > patch applied. See http://pgci.eisentraut.org/jenkins/job/postgresql_commitfest_world/46/consoleFull Perhaps you didn't build with --enable-cassert?
Thanks for getting back to me about this change Oleg. I took your advice and reworked the patch by adding a new hstore gin opclass (gin_hstore_combined_ops) and leaving the functionality of the default hstore gin opclass the same. This should prevent the on-disk compatibility issues from the first patch, and allow users to select the different indexing method when they build the index. The hstore regression suite is passing for me locally with the --enable-cassert configure flag. Please let me know what you think and if there is any other work that would need to be done (style cleanups, updating documentation, etc) to get this merged.
Thanks!
Blake
On Fri, Sep 6, 2013 at 1:47 PM, Oleg Bartunov <obartunov@gmail.com> wrote:
OlegBlake,I think it's better to implement this patch as a separate opclass, so users will have option to choose indexing.On Tue, Sep 3, 2013 at 6:24 PM, Blake Smith <blakesmith0@gmail.com> wrote:Thanks for the feedback everyone. I've attached the patch that we are now running in production to service our hstore include queries. We rebuilt the index to account for the on-disk incompatibility. I've submitted the patch to commitfest here: https://commitfest.postgresql.org/action/patch_view?id=1203Michael: I don't have a formal benchmark, but several of our worst queries went from 10-20 seconds per query down to 50-400 ms. These are numbers we've seen when testing real production queries against our production dataset with real world access patterns.Oleg: Thanks for your thoughts on this change. As for the spgist / gin work you're doing, is there anything you need help with or are you still in the research phase? I'd love to help get something more robust merged into mainline if you think there's collaborative work to be done (even if it's only user testing).Thanks,BlakeBlake SmithOn Wed, Aug 28, 2013 at 12:40 PM, Andres Freund <andres@2ndquadrant.com> wrote:But that really cannot be acceptable for hstore. The probably mostOn 2013-08-28 13:31:22 -0400, Bruce Momjian wrote:
> On Sun, Aug 25, 2013 at 10:11:50PM -0400, Tom Lane wrote:
> > Michael Paquier <michael.paquier@gmail.com> writes:
> > > On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote:
> > >> The combined entry is used to support "contains (@>)" queries, and the key
> > >> only item is used to support "key contains (?)" queries. This change seems
> > >> to help especially with hstore keys that have high cardinalities. Downsides
> > >> of this change is that it requires an index rebuild, and the index will be
> > >> larger in size.
> >
> > > Index rebuild would be a problem only for minor releases,
> >
> > That's completely false; people have expected major releases to be
> > on-disk-compatible for several years now. While there probably will be
> > future releases in which we are willing to break storage compatibility,
> > a contrib module doesn't get to dictate that.
> >
> > What might be a practical solution, especially if this isn't always a
> > win (which seems likely given the index-bloat risk), is to make hstore
> > offer two different GIN index opclasses, one that works the traditional
> > way and one that works this way.
> >
> > Another thing that needs to be taken into account here is Oleg and
> > Teodor's in-progress work on extending hstore:
> > https://www.pgcon.org/2013/schedule/events/518.en.html
> > I'm not sure if this patch would conflict with that at all, but it
> > needs to be considered.
>
> We can disallow in-place upgrades for clusters that use certain contrib
> modules --- we have done that in the past.
widely used extension there is.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services--
http://blakesmith.me@blakesmith--
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Blake Smith
http://blakesmith.me
@blakesmith
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Blake,
Teodor will review your patch, but I have one consideration about the patch in context of future hstore, which supports hierarchical structures. In that case overhead of composite keys will be enormous and the only way in this direction is to think about idea suffix array instead of btree to store keys. But this is another big task and I afraid to think about this now. On Mon, Sep 9, 2013 at 6:55 PM, Blake Smith <blakesmith0@gmail.com> wrote:
Thanks for getting back to me about this change Oleg. I took your advice and reworked the patch by adding a new hstore gin opclass (gin_hstore_combined_ops) and leaving the functionality of the default hstore gin opclass the same. This should prevent the on-disk compatibility issues from the first patch, and allow users to select the different indexing method when they build the index. The hstore regression suite is passing for me locally with the --enable-cassert configure flag. Please let me know what you think and if there is any other work that would need to be done (style cleanups, updating documentation, etc) to get this merged.Thanks!BlakeOn Fri, Sep 6, 2013 at 1:47 PM, Oleg Bartunov <obartunov@gmail.com> wrote:OlegBlake,I think it's better to implement this patch as a separate opclass, so users will have option to choose indexing.On Tue, Sep 3, 2013 at 6:24 PM, Blake Smith <blakesmith0@gmail.com> wrote:Thanks for the feedback everyone. I've attached the patch that we are now running in production to service our hstore include queries. We rebuilt the index to account for the on-disk incompatibility. I've submitted the patch to commitfest here: https://commitfest.postgresql.org/action/patch_view?id=1203Michael: I don't have a formal benchmark, but several of our worst queries went from 10-20 seconds per query down to 50-400 ms. These are numbers we've seen when testing real production queries against our production dataset with real world access patterns.Oleg: Thanks for your thoughts on this change. As for the spgist / gin work you're doing, is there anything you need help with or are you still in the research phase? I'd love to help get something more robust merged into mainline if you think there's collaborative work to be done (even if it's only user testing).Thanks,BlakeBlake SmithOn Wed, Aug 28, 2013 at 12:40 PM, Andres Freund <andres@2ndquadrant.com> wrote:But that really cannot be acceptable for hstore. The probably mostOn 2013-08-28 13:31:22 -0400, Bruce Momjian wrote:
> On Sun, Aug 25, 2013 at 10:11:50PM -0400, Tom Lane wrote:
> > Michael Paquier <michael.paquier@gmail.com> writes:
> > > On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith <blakesmith0@gmail.com> wrote:
> > >> The combined entry is used to support "contains (@>)" queries, and the key
> > >> only item is used to support "key contains (?)" queries. This change seems
> > >> to help especially with hstore keys that have high cardinalities. Downsides
> > >> of this change is that it requires an index rebuild, and the index will be
> > >> larger in size.
> >
> > > Index rebuild would be a problem only for minor releases,
> >
> > That's completely false; people have expected major releases to be
> > on-disk-compatible for several years now. While there probably will be
> > future releases in which we are willing to break storage compatibility,
> > a contrib module doesn't get to dictate that.
> >
> > What might be a practical solution, especially if this isn't always a
> > win (which seems likely given the index-bloat risk), is to make hstore
> > offer two different GIN index opclasses, one that works the traditional
> > way and one that works this way.
> >
> > Another thing that needs to be taken into account here is Oleg and
> > Teodor's in-progress work on extending hstore:
> > https://www.pgcon.org/2013/schedule/events/518.en.html
> > I'm not sure if this patch would conflict with that at all, but it
> > needs to be considered.
>
> We can disallow in-place upgrades for clusters that use certain contrib
> modules --- we have done that in the past.
widely used extension there is.
Greetings,
Andres Freund
--
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http://blakesmith.me@blakesmith--
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Blake Smith
http://blakesmith.me@blakesmith
Blake, I've taken the liberty of adding this patch to the current Commitfest. In future, please continue to send patches both to this thread and to the commitfest application when you have a message ID for them :) Cheers, David. On Mon, Sep 09, 2013 at 09:55:01AM -0500, Blake Smith wrote: > Thanks for getting back to me about this change Oleg. I took your advice > and reworked the patch by adding a new hstore gin opclass > (gin_hstore_combined_ops) and leaving the functionality of the default > hstore gin opclass the same. This should prevent the on-disk compatibility > issues from the first patch, and allow users to select the different > indexing method when they build the index. The hstore regression suite is > passing for me locally with the --enable-cassert configure flag. Please let > me know what you think and if there is any other work that would need to be > done (style cleanups, updating documentation, etc) to get this merged. > > Thanks! > > Blake > > > > > > > On Fri, Sep 6, 2013 at 1:47 PM, Oleg Bartunov <obartunov@gmail.com> wrote: > > > Blake, > > > > I think it's better to implement this patch as a separate opclass, so > > users will have option to choose indexing. > > > > Oleg > > > > > > On Tue, Sep 3, 2013 at 6:24 PM, Blake Smith <blakesmith0@gmail.com> wrote: > > > >> Thanks for the feedback everyone. I've attached the patch that we are now > >> running in production to service our hstore include queries. We rebuilt the > >> index to account for the on-disk incompatibility. I've submitted the patch > >> to commitfest here: > >> https://commitfest.postgresql.org/action/patch_view?id=1203 > >> > >> Michael: I don't have a formal benchmark, but several of our worst > >> queries went from 10-20 seconds per query down to 50-400 ms. These are > >> numbers we've seen when testing real production queries against our > >> production dataset with real world access patterns. > >> Oleg: Thanks for your thoughts on this change. As for the spgist / gin > >> work you're doing, is there anything you need help with or are you still in > >> the research phase? I'd love to help get something more robust merged into > >> mainline if you think there's collaborative work to be done (even if it's > >> only user testing). > >> > >> Thanks, > >> > >> Blake > >> > >> > >> > >> > >> On Wed, Aug 28, 2013 at 12:40 PM, Andres Freund <andres@2ndquadrant.com>wrote: > >> > >>> On 2013-08-28 13:31:22 -0400, Bruce Momjian wrote: > >>> > On Sun, Aug 25, 2013 at 10:11:50PM -0400, Tom Lane wrote: > >>> > > Michael Paquier <michael.paquier@gmail.com> writes: > >>> > > > On Thu, Aug 22, 2013 at 11:55 PM, Blake Smith < > >>> blakesmith0@gmail.com> wrote: > >>> > > >> The combined entry is used to support "contains (@>)" queries, > >>> and the key > >>> > > >> only item is used to support "key contains (?)" queries. This > >>> change seems > >>> > > >> to help especially with hstore keys that have high cardinalities. > >>> Downsides > >>> > > >> of this change is that it requires an index rebuild, and the > >>> index will be > >>> > > >> larger in size. > >>> > > > >>> > > > Index rebuild would be a problem only for minor releases, > >>> > > > >>> > > That's completely false; people have expected major releases to be > >>> > > on-disk-compatible for several years now. While there probably will > >>> be > >>> > > future releases in which we are willing to break storage > >>> compatibility, > >>> > > a contrib module doesn't get to dictate that. > >>> > > > >>> > > What might be a practical solution, especially if this isn't always a > >>> > > win (which seems likely given the index-bloat risk), is to make > >>> hstore > >>> > > offer two different GIN index opclasses, one that works the > >>> traditional > >>> > > way and one that works this way. > >>> > > > >>> > > Another thing that needs to be taken into account here is Oleg and > >>> > > Teodor's in-progress work on extending hstore: > >>> > > https://www.pgcon.org/2013/schedule/events/518.en.html > >>> > > I'm not sure if this patch would conflict with that at all, but it > >>> > > needs to be considered. > >>> > > >>> > We can disallow in-place upgrades for clusters that use certain contrib > >>> > modules --- we have done that in the past. > >>> > >>> But that really cannot be acceptable for hstore. The probably most > >>> widely used extension there is. > >>> > >>> Greetings, > >>> > >>> Andres Freund > >>> > >>> -- > >>> Andres Freund http://www.2ndQuadrant.com/ > >>> PostgreSQL Development, 24x7 Support, Training & Services > >>> > >> > >> > >> > >> -- > >> Blake Smith > >> http://blakesmith.me > >> @blakesmith > >> > >> > >> -- > >> Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > >> To make changes to your subscription: > >> http://www.postgresql.org/mailpref/pgsql-hackers > >> > >> > > > > > -- > Blake Smith > http://blakesmith.me > @blakesmith > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! 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Are you still working on this patch?