REINDEX checking of index constraints

Started by Noah Mischabout 13 years ago7 messageshackers
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#1Noah Misch
noah@leadboat.com

Historically, REINDEX would always revalidate any uniqueness enforced by the
index. An EDB customer reported that this is not happening, and indeed I
broke it way back in commit 8ceb24568054232696dddc1166a8563bc78c900a.
Specifically, REINDEX TABLE and REINDEX DATABASE no longer revalidate
constraints, but REINDEX INDEX still does so. As a consequence, REINDEX INDEX
is the only form of REINDEX that fixes a failed CREATE INDEX CONCURRENTLY.

Attached patch just restores the old behavior. Would it be worth preserving
the ability to fix an index consistency problem with a REINDEX independent
from related heap consistency problems such as duplicate keys?

Thanks,
nm

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Noah Misch
EnterpriseDB http://www.enterprisedb.com

Attachments:

reindex-constraints-v1.patchtext/plain; charset=us-asciiDownload+45-29
#2Josh Berkus
josh@agliodbs.com
In reply to: Noah Misch (#1)
Re: REINDEX checking of index constraints

Noah,

Attached patch just restores the old behavior. Would it be worth preserving
the ability to fix an index consistency problem with a REINDEX independent
from related heap consistency problems such as duplicate keys?

I would love to have two versions of REINDEX, one which validated and
one which didn't. Maybe a ( validate off ) type check?

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PostgreSQL Experts Inc.
http://pgexperts.com

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#3Josh Berkus
josh@agliodbs.com
In reply to: Noah Misch (#1)
Re: REINDEX checking of index constraints

On 07/21/2013 11:30 AM, Josh Berkus wrote:

Noah,

Attached patch just restores the old behavior. Would it be worth preserving
the ability to fix an index consistency problem with a REINDEX independent
from related heap consistency problems such as duplicate keys?

I would love to have two versions of REINDEX, one which validated and
one which didn't. Maybe a ( validate off ) type check?

Cancel this. I just did some tests, and there amount of time required
for the validation (at least, in simple two-column table test) is < 10%
of the time required to reindex in general. At that difference, we
don't need two options.

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#4Josh Berkus
josh@agliodbs.com
In reply to: Noah Misch (#1)
Re: REINDEX checking of index constraints

On 07/21/2013 11:30 AM, Josh Berkus wrote:

Noah,

Attached patch just restores the old behavior. Would it be worth preserving
the ability to fix an index consistency problem with a REINDEX independent
from related heap consistency problems such as duplicate keys?

I would love to have two versions of REINDEX, one which validated and
one which didn't. Maybe a ( validate off ) type check?

Cancel this. I just did some tests, and there amount of time required
for the validation (at least, in simple two-column table test) is < 10%
of the time required to reindex in general. At that difference, we
don't need two options.

Unless you're asking if we want a command to check the index validity
without rebuilding it? That might be more valuable ...

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#5Kenneth Marshall
ktm@rice.edu
In reply to: Josh Berkus (#2)
Re: REINDEX checking of index constraints

On Sun, Jul 21, 2013 at 11:30:54AM -0700, Josh Berkus wrote:

Noah,

Attached patch just restores the old behavior. Would it be worth preserving
the ability to fix an index consistency problem with a REINDEX independent
from related heap consistency problems such as duplicate keys?

I would love to have two versions of REINDEX, one which validated and
one which didn't. Maybe a ( validate off ) type check?

+1 There are reasons to reindex that do not involve its validity and it would
be great to not need to visit the heap for that.

Regards,
Ken

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#6Noah Misch
noah@leadboat.com
In reply to: Josh Berkus (#4)
Re: REINDEX checking of index constraints

On Sun, Jul 21, 2013 at 01:47:00PM -0700, Josh Berkus wrote:

On 07/21/2013 11:30 AM, Josh Berkus wrote:

Attached patch just restores the old behavior. Would it be worth preserving
the ability to fix an index consistency problem with a REINDEX independent
from related heap consistency problems such as duplicate keys?

I would love to have two versions of REINDEX, one which validated and
one which didn't. Maybe a ( validate off ) type check?

Cancel this. I just did some tests, and there amount of time required
for the validation (at least, in simple two-column table test) is < 10%
of the time required to reindex in general. At that difference, we
don't need two options.

Unless you're asking if we want a command to check the index validity
without rebuilding it? That might be more valuable ...

I meant to ask whether, instead of reverting the accidental behavior change,
we should do something like leave the behavior and change the documentation
instead. I personally vote "no", but that alternative seemed credible enough
to justify mentioning it. Something more radical, like a new UI, would be a
separate patch.

Thanks,
nm

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Noah Misch
EnterpriseDB http://www.enterprisedb.com

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#7Alvaro Herrera
alvherre@2ndquadrant.com
In reply to: Noah Misch (#6)
Re: REINDEX checking of index constraints

Noah Misch wrote:

I meant to ask whether, instead of reverting the accidental behavior change,
we should do something like leave the behavior and change the documentation
instead. I personally vote "no", but that alternative seemed credible enough
to justify mentioning it. Something more radical, like a new UI, would be a
separate patch.

separate patch++. I agree some use cases probably justify new UI.

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PostgreSQL Development, 24x7 Support, Training & Services

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