btree index maximum row size

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btree index maximum row size

apt.postgresql.org Repository Update
The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/12/limits.html
Description:

Appendix K (PostgreSQL Limits) - doesn't mention the (btree) index row size
limits. I think that it should.
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Re: btree index maximum row size

Bruce Momjian
On Mon, Feb  3, 2020 at 07:09:19PM +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
>
> Page: https://www.postgresql.org/docs/12/limits.html
> Description:
>
> Appendix K (PostgreSQL Limits) - doesn't mention the (btree) index row size
> limits. I think that it should.

Sorry for the delay in replying.  We do get questions about the btree
length limit occasionally, but practically the length limit usually
isn't a problem.  Unless you need ordered data, a hash index is a better
choice for long values than btree because the hashes are much shorter.
Expression indexes can also help.

What is your use-case for indexing very long values?

--
  Bruce Momjian  <[hidden email]>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

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Re: btree index maximum row size

Peter Geoghegan-4
On Thu, Mar 12, 2020 at 5:17 PM Bruce Momjian <[hidden email]> wrote:
> Sorry for the delay in replying.  We do get questions about the btree
> length limit occasionally, but practically the length limit usually
> isn't a problem.

Technically the limitation is documented elsewhere, since it is a
limitation of the B-Tree access method specifically. However, I think
that there is a good practical argument to be made for including it
here as well.

--
Peter Geoghegan