As an optimization, we store "name" columns as cstrings in btree
indexes.
Here we modify it so that Index Only Scans convert these cstrings back
to names with NAMEDATALEN bytes rather than storing the cstring in the
tuple slot, as was happening previously.
Bug: #17855
Reported-by: Alexander Lakhin
Reviewed-by: Alexander Lakhin, Tom Lane
Discussion: https://postgr.es/m/17855-5f523e0f9769a566@postgresql.org
Backpatch-through: 12, all supported versions
Similar to xid, but 64 bits wide. This new type is suitable for use in
various system views and administration functions.
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Takao Fujii <btfujiitkp@oss.nttdata.com>
Reviewed-by: Yoshikazu Imai <imai.yoshikazu@fujitsu.com>
Reviewed-by: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://postgr.es/m/20190725000636.666m5mad25wfbrri%40alap3.anarazel.de
text_pattern_ops and its siblings can't be used with nondeterministic
collations, because they use the text_eq operator which will not behave
as bitwise equality if applied with a nondeterministic collation. The
initial implementation of that restriction was to insert a run-time test
in the related comparison functions, but that is inefficient, may throw
misleading errors, and will throw errors in some cases that would work.
It seems sufficient to just prevent the combination during CREATE INDEX,
so do that instead.
Lacking any better way to identify the opclasses involved, we need to
hard-wire tests for them, which requires hand-assigned values for their
OIDs, which forces a catversion bump because they previously had OIDs
that would be assigned automatically. That's slightly annoying in the
v12 branch, but fortunately we're not at rc1 yet, so just do it.
Back-patch to v12 where nondeterministic collations were added.
In passing, run make reformat-dat-files, which found some unrelated
whitespace issues (slightly different ones in HEAD and v12).
Peter Eisentraut, with small corrections by me
Discussion: https://postgr.es/m/22566.1568675619@sss.pgh.pa.us
Up to now we've not worried much about joins where the join key is a
relation's CTID column, reasoning that storing a table's CTIDs in some
other table would be pretty useless. However, there are use-cases for
this sort of query involving self-joins, so that argument doesn't really
hold water.
With larger relations, a merge or hash join is desirable. We had a btree
opclass for type "tid", allowing merge joins on CTID, but no hash opclass
so that hash joins weren't possible. Add the missing infrastructure.
This also potentially enables hash aggregation on "tid", though the
use-cases for that aren't too clear.
Discussion: https://postgr.es/m/1853.1545453106@sss.pgh.pa.us
Now that name comparison has effectively the same behavior as text
comparison, we might as well merge the name_ops opfamily into text_ops,
allowing cross-type comparisons to be processed without forcing a
datatype coercion first. We need do little more than add cross-type
operators to make the opfamily complete, and fix one or two places
in the planner that assumed text_ops was a single-datatype opfamily.
I chose to unify hash name_ops into hash text_ops as well, since the
types have compatible hashing semantics. This allows marking the
new cross-type equality operators as oprcanhash.
(Note: this doesn't remove the name_ops opclasses, so there's no
breakage of index definitions. Those opclasses are just reparented
into the text_ops opfamily.)
Discussion: https://postgr.es/m/15938.1544377821@sss.pgh.pa.us
Use the term "system catalog" rather than "system relation" in assorted
places where it's clearly referring to a table rather than, say, an
index. Use more natural word order in the header boilerplate, improve
some of the one-liner catalog descriptions, and fix assorted random
deviations from the normal boilerplate. All purely neatnik-ism, but
why not.
John Naylor, some additional cleanup by me
Discussion: https://postgr.es/m/CAJVSVGUeJmFB3h-NJ18P32NPa+kzC165nm7GSoGHfPaN80Wxcw@mail.gmail.com
Historically, the initial catalog data to be installed during bootstrap
has been written in DATA() lines in the catalog header files. This had
lots of disadvantages: the format was badly underdocumented, it was
very difficult to edit the data in any mechanized way, and due to the
lack of any abstraction the data was verbose, hard to read/understand,
and easy to get wrong.
Hence, move this data into separate ".dat" files and represent it in a way
that can easily be read and rewritten by Perl scripts. The new format is
essentially "key => value" for each column; while it's a bit repetitive,
explicit labeling of each value makes the data far more readable and less
error-prone. Provide a way to abbreviate entries by omitting field values
that match a specified default value for their column. This allows removal
of a large amount of repetitive boilerplate and also lowers the barrier to
adding new columns.
Also teach genbki.pl how to translate symbolic OID references into
numeric OIDs for more cases than just "regproc"-like pg_proc references.
It can now do that for regprocedure-like references (thus solving the
problem that regproc is ambiguous for overloaded functions), operators,
types, opfamilies, opclasses, and access methods. Use this to turn
nearly all OID cross-references in the initial data into symbolic form.
This represents a very large step forward in readability and error
resistance of the initial catalog data. It should also reduce the
difficulty of renumbering OID assignments in uncommitted patches.
Also, solve the longstanding problem that frontend code that would like to
use OID macros and other information from the catalog headers often had
difficulty with backend-only code in the headers. To do this, arrange for
all generated macros, plus such other declarations as we deem fit, to be
placed in "derived" header files that are safe for frontend inclusion.
(Once clients migrate to using these pg_*_d.h headers, it will be possible
to get rid of the pg_*_fn.h headers, which only exist to quarantine code
away from clients. That is left for follow-on patches, however.)
The now-automatically-generated macros include the Anum_xxx and Natts_xxx
constants that we used to have to update by hand when adding or removing
catalog columns.
Replace the former manual method of generating OID macros for pg_type
entries with an automatic method, ensuring that all built-in types have
OID macros. (But note that this patch does not change the way that
OID macros for pg_proc entries are built and used. It's not clear that
making that match the other catalogs would be worth extra code churn.)
Add SGML documentation explaining what the new data format is and how to
work with it.
Despite being a very large change in the catalog headers, there is no
catversion bump here, because postgres.bki and related output files
haven't changed at all.
John Naylor, based on ideas from various people; review and minor
additional coding by me; previous review by Alvaro Herrera
Discussion: https://postgr.es/m/CAJVSVGWO48JbbwXkJz_yBFyGYW-M9YWxnPdxJBUosDC9ou_F0Q@mail.gmail.com
David Rowley
Thomas Munro
Bruce Momjian
Tom Lane
Andres Freund