Commit Graph

222 Commits

Author SHA1 Message Date
Magnus Hagander d00ca333c3 Implement array version of jsonb_delete and operator
This makes it possible to delete multiple keys from a jsonb value by
passing in an array of text values, which makes the operaiton much
faster than individually deleting the keys (which would require copying
the jsonb structure over and over again.

Reviewed by Dmitry Dolgov and Michael Paquier
2017-01-18 21:37:59 +01:00
Peter Eisentraut 323b96aa34 Register missing money operators in system catalogs
The operators money*int8, int8*money, and money/int8 were implemented in
code but not registered in pg_operator or pg_proc.

Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
2017-01-17 12:36:02 -05:00
Bruce Momjian 1d25779284 Update copyright via script for 2017 2017-01-03 13:48:53 -05:00
Tom Lane 5c80642aa8 Remove unnecessary int2vector-specific hash function and equality operator.
These functions were originally added in commit d8cedf67a to support
use of int2vector columns as catcache lookup keys.  However, there are
no catcaches that use such columns.  (Indeed I now think it must always
have been dead code: a catcache with such a key column would need an
underlying unique index on the column, but we've never had an int2vector
btree opclass.)

Getting rid of the int2vector-specific operator and function does not
lose any functionality, because operations on int2vectors will now fall
back to the generic anyarray support.  This avoids a wart that a btree
index on an int2vector column (made using anyarray_ops) would fail to
match equality searches, because int2vectoreq wasn't a member of the
opclass.  We don't really care much about that, since int2vector is not
meant as a type for users to use, but it's silly to have extra code and
less functionality.

If we ever do want a catcache to be indexed by an int2vector column,
we'd need to put back full btree and hash opclasses for int2vector,
comparable to the support for oidvector.  (The anyarray code can't be
used at such a low level, because it needs to do catcache lookups.)
But we'll deal with that if/when the need arises.

Also worth noting is that removal of the hash int2vector_ops opclass will
break any user-created hash indexes on int2vector columns.  While hash
anyarray_ops would serve the same purpose, it would probably not compute
the same hash values and thus wouldn't be on-disk-compatible.  Given that
int2vector isn't a user-facing type and we're planning other incompatible
changes in hash indexes for v10 anyway, this doesn't seem like something
to worry about, but it's probably worth mentioning here.

Amit Langote

Discussion: <d9bb74f8-b194-7307-9ebd-90645d377e45@lab.ntt.co.jp>
2016-10-12 14:54:08 -04:00
Robert Haas 4bc424b968 pgindent run for 9.6 2016-06-09 18:02:36 -04:00
Teodor Sigaev bb140506df Phrase full text search.
Patch introduces new text search operator (<-> or <DISTANCE>) into tsquery.
On-disk and binary in/out format of tsquery are backward compatible.
It has two side effect:
- change order for tsquery, so, users, who has a btree index over tsquery,
  should reindex it
- less number of parenthesis in tsquery output, and tsquery becomes more
  readable

Authors: Teodor Sigaev, Oleg Bartunov, Dmitry Ivanov
Reviewers: Alexander Korotkov, Artur Zakirov
2016-04-07 18:44:18 +03:00
Bruce Momjian ee94300446 Update copyright for 2016
Backpatch certain files through 9.1
2016-01-02 13:33:40 -05:00
Tom Lane 0dab5ef39b Fix ALTER OPERATOR to update dependencies properly.
Fix an oversight in commit 321eed5f0f7563a0: replacing an operator's
selectivity functions needs to result in a corresponding update in
pg_depend.  We have a function that can handle that, but it was not
called by AlterOperator().

To fix this without enlarging pg_operator.h's #include list beyond
what clients can safely include, split off the function definitions
into a new file pg_operator_fn.h, similarly to what we've done for
some other catalog header files.  It's not entirely clear whether
any client-side code needs to include pg_operator.h, but it seems
prudent to assume that there is some such code somewhere.
2015-12-31 17:37:31 -05:00
Tom Lane c5e86ea932 Add "xid <> xid" and "xid <> int4" operators.
The corresponding "=" operators have been there a long time, and not
having their negators is a bit of a nuisance.

Michael Paquier
2015-11-07 16:40:15 -05:00
Bruce Momjian b852dc4cbd docs: clarify JSONB operator descriptions
No catalog bump as the catalog changes are for SQL operator comments.

Backpatch through 9.5
2015-10-07 09:06:49 -04:00
Andrew Dunstan 908e234733 Rename jsonb - text[] operator to #- to avoid ambiguity.
Following recent discussion  on -hackers. The underlying function is
also renamed to jsonb_delete_path. The regression tests now don't need
ugly type casts to avoid the ambiguity, so they are also removed.

Catalog version bumped.
2015-06-11 10:06:58 -04:00
Bruce Momjian 807b9e0dff pgindent run for 9.5 2015-05-23 21:35:49 -04:00
Heikki Linnakangas 35fcb1b3d0 Allow GiST distance function to return merely a lower-bound.
The distance function can now set *recheck = false, like index quals. The
executor will then re-check the ORDER BY expressions, and use a queue to
reorder the results on the fly.

This makes it possible to do kNN-searches on polygons and circles, which
don't store the exact value in the index, but just a bounding box.

Alexander Korotkov and me
2015-05-15 14:26:51 +03:00
Andrew Dunstan c6947010ce Additional functions and operators for jsonb
jsonb_pretty(jsonb) produces nicely indented json output.
jsonb || jsonb concatenates two jsonb values.
jsonb - text removes a key and its associated value from the json
jsonb - int removes the designated array element
jsonb - text[] removes a key and associated value or array element at
the designated path
jsonb_replace(jsonb,text[],jsonb) replaces the array element designated
by the path or the value associated with the key designated by the path
with the given value.

Original work by Dmitry Dolgov, adapted and reworked for PostgreSQL core
by Andrew Dunstan, reviewed and tidied up by Petr Jelinek.
2015-05-12 15:52:45 -04:00
Alvaro Herrera a2e35b53c3 Change many routines to return ObjectAddress rather than OID
The changed routines are mostly those that can be directly called by
ProcessUtilitySlow; the intention is to make the affected object
information more precise, in support for future event trigger changes.
Originally it was envisioned that the OID of the affected object would
be enough, and in most cases that is correct, but upon actually
implementing the event trigger changes it turned out that ObjectAddress
is more widely useful.

Additionally, some command execution routines grew an output argument
that's an object address which provides further info about the executed
command.  To wit:

* for ALTER DOMAIN / ADD CONSTRAINT, it corresponds to the address of
  the new constraint

* for ALTER OBJECT / SET SCHEMA, it corresponds to the address of the
  schema that originally contained the object.

* for ALTER EXTENSION {ADD, DROP} OBJECT, it corresponds to the address
  of the object added to or dropped from the extension.

There's no user-visible change in this commit, and no functional change
either.

Discussion: 20150218213255.GC6717@tamriel.snowman.net
Reviewed-By: Stephen Frost, Andres Freund
2015-03-03 14:10:50 -03:00
Tom Lane 3d660d33aa Fix assorted oversights in range selectivity estimation.
calc_rangesel() failed outright when comparing range variables to empty
constant ranges with < or >=, as a result of missing cases in a switch.
It also produced a bogus estimate for > comparison to an empty range.

On top of that, the >= and > cases were mislabeled throughout.  For
nonempty constant ranges, they managed to produce the right answers
anyway as a result of counterbalancing typos.

Also, default_range_selectivity() omitted cases for elem <@ range,
range &< range, and range &> range, so that rather dubious defaults
were applied for these operators.

In passing, rearrange the code in rangesel() so that the elem <@ range
case is handled in a less opaque fashion.

Report and patch by Emre Hasegeli, some additional work by me
2015-01-30 12:30:59 -05:00
Bruce Momjian 4baaf863ec Update copyright for 2015
Backpatch certain files through 9.0
2015-01-06 11:43:47 -05:00
Heikki Linnakangas 4520ba6769 Add point <-> polygon distance operator.
Alexander Korotkov, reviewed by Emre Hasegeli.
2014-12-15 17:06:21 +02:00
Tom Lane 866737c923 Add a #define for the inet overlaps operator.
Extracted from pending inet selectivity patch.  The rest of it isn't
quite ready to commit, but we might as well push this part so the patch
doesn't have to track the moving target of pg_operator.h.
2014-11-30 19:43:43 -05:00
Tom Lane e3f9c16838 Fix bogus commutator/negator links for JSONB containment operators.
<@ and @> are each other's commutators, but they were incorrectly marked
as being each other's negators instead.  (This was actually questioned
in a comment in the original commit, but nobody followed through :-(.)
Per bug #11178 from Christian Pronovost.

In passing, fix some JSONB operator descriptions that were randomly
different from the phrasing of every other similar description.

catversion bump for pg_catalog contents change.
2014-08-16 12:53:54 -04:00
Tom Lane f71136eeeb Get rid of bogus separate pg_proc entries for json_extract_path operators.
These should not have existed to begin with, but there was apparently some
misunderstanding of the purpose of the opr_sanity regression test item
that checks for operator implementation functions with their own comments.
The idea there is to check for unintentional violations of the rule that
operator implementation functions shouldn't be documented separately
.... but for these functions, that is in fact what we want, since the
variadic option is useful and not accessible via the operator syntax.
Get rid of the extra pg_proc entries and fix the regression test and
documentation to be explicit about what we're doing here.
2014-06-26 16:22:15 -07:00
Tom Lane 4c8ab1b91d Add btree and hash opclasses for pg_lsn.
This is needed to allow ORDER BY, DISTINCT, etc to work as expected for
pg_lsn values.

We had previously decided to put this off for 9.5, but in view of commit
eeca4cd35e there's no reason to avoid a
catversion bump for 9.4beta2, and this does make a pretty significant
usability difference for pg_lsn.

Michael Paquier, with fixes from Andres Freund and Tom Lane
2014-06-04 20:45:56 -04:00
Tom Lane f23a5630eb Add an in-core GiST index opclass for inet/cidr types.
This operator class can accelerate subnet/supernet tests as well as
btree-equivalent ordered comparisons.  It also handles a new network
operator inet && inet (overlaps, a/k/a "is supernet or subnet of"),
which is expected to be useful in exclusion constraints.

Ideally this opclass would be the default for GiST with inet/cidr data,
but we can't mark it that way until we figure out how to do a more or
less graceful transition from the current situation, in which the
really-completely-bogus inet/cidr opclasses in contrib/btree_gist are
marked as default.  Having the opclass in core and not default is better
than not having it at all, though.

While at it, add new documentation sections to allow us to officially
document GiST/GIN/SP-GiST opclasses, something there was never a clear
place to do before.  I filled these in with some simple tables listing
the existing opclasses and the operators they support, but there's
certainly scope to put more information there.

Emre Hasegeli, reviewed by Andreas Karlsson, further hacking by me
2014-04-08 15:46:43 -04:00
Andrew Dunstan d9134d0a35 Introduce jsonb, a structured format for storing json.
The new format accepts exactly the same data as the json type. However, it is
stored in a format that does not require reparsing the orgiginal text in order
to process it, making it much more suitable for indexing and other operations.
Insignificant whitespace is discarded, and the order of object keys is not
preserved. Neither are duplicate object keys kept - the later value for a given
key is the only one stored.

The new type has all the functions and operators that the json type has,
with the exception of the json generation functions (to_json, json_agg etc.)
and with identical semantics. In addition, there are operator classes for
hash and btree indexing, and two classes for GIN indexing, that have no
equivalent in the json type.

This feature grew out of previous work by Oleg Bartunov and Teodor Sigaev, which
was intended to provide similar facilities to a nested hstore type, but which
in the end proved to have some significant compatibility issues.

Authors: Oleg Bartunov,  Teodor Sigaev, Peter Geoghegan and Andrew Dunstan.
Review: Andres Freund
2014-03-23 16:40:19 -04:00
Robert Haas 7d03a83f4d Add a pg_lsn data type, to represent an LSN.
Robert Haas and Michael Paquier
2014-02-19 08:35:23 -05:00
Bruce Momjian 7e04792a1c Update copyright for 2014
Update all files in head, and files COPYRIGHT and legal.sgml in all back
branches.
2014-01-07 16:05:30 -05:00
Tom Lane 8b49a6044d Cache catalog lookup data across groups in ordered-set aggregates.
The initial commit of ordered-set aggregates just did all the setup work
afresh each time the aggregate function is started up.  But in a GROUP BY
query, the catalog lookups need not be repeated for each group, since the
column datatypes and sort information won't change.  When there are many
small groups, this makes for a useful, though not huge, performance
improvement.  Per suggestion from Andrew Gierth.

Profiling of these cases suggests that it might be profitable to avoid
duplicate lookups within tuplesort startup as well; but changing the
tuplesort APIs would have much broader impact, so I left that for
another day.
2014-01-05 12:28:39 -05:00
Tom Lane 8d65da1f01 Support ordered-set (WITHIN GROUP) aggregates.
This patch introduces generic support for ordered-set and hypothetical-set
aggregate functions, as well as implementations of the instances defined in
SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(),
percent_rank(), cume_dist()).  We also added mode() though it is not in the
spec, as well as versions of percentile_cont() and percentile_disc() that
can compute multiple percentile values in one pass over the data.

Unlike the original submission, this patch puts full control of the sorting
process in the hands of the aggregate's support functions.  To allow the
support functions to find out how they're supposed to sort, a new API
function AggGetAggref() is added to nodeAgg.c.  This allows retrieval of
the aggregate call's Aggref node, which may have other uses beyond the
immediate need.  There is also support for ordered-set aggregates to
install cleanup callback functions, so that they can be sure that
infrastructure such as tuplesort objects gets cleaned up.

In passing, make some fixes in the recently-added support for variadic
aggregates, and make some editorial adjustments in the recent FILTER
additions for aggregates.  Also, simplify use of IsBinaryCoercible() by
allowing it to succeed whenever the target type is ANY or ANYELEMENT.
It was inconsistent that it dealt with other polymorphic target types
but not these.

Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing,
and rather heavily editorialized upon by Tom Lane
2013-12-23 16:11:35 -05:00
Tom Lane 784e762e88 Support multi-argument UNNEST(), and TABLE() syntax for multiple functions.
This patch adds the ability to write TABLE( function1(), function2(), ...)
as a single FROM-clause entry.  The result is the concatenation of the
first row from each function, followed by the second row from each
function, etc; with NULLs inserted if any function produces fewer rows than
others.  This is believed to be a much more useful behavior than what
Postgres currently does with multiple SRFs in a SELECT list.

This syntax also provides a reasonable way to combine use of column
definition lists with WITH ORDINALITY: put the column definition list
inside TABLE(), where it's clear that it doesn't control the ordinality
column as well.

Also implement SQL-compliant multiple-argument UNNEST(), by turning
UNNEST(a,b,c) into TABLE(unnest(a), unnest(b), unnest(c)).

The SQL standard specifies TABLE() with only a single function, not
multiple functions, and it seems to require an implicit UNNEST() which is
not what this patch does.  There may be something wrong with that reading
of the spec, though, because if it's right then the spec's TABLE() is just
a pointless alternative spelling of UNNEST().  After further review of
that, we might choose to adopt a different syntax for what this patch does,
but in any case this functionality seems clearly worthwhile.

Andrew Gierth, reviewed by Zoltán Böszörményi and Heikki Linnakangas, and
significantly revised by me
2013-11-21 19:37:20 -05:00
Kevin Grittner f566515192 Add record_image_ops opclass for matview concurrent refresh.
REFRESH MATERIALIZED VIEW CONCURRENTLY was broken for any matview
containing a column of a type without a default btree operator
class.  It also did not produce results consistent with a non-
concurrent REFRESH or a normal view if any column was of a type
which allowed user-visible differences between values which
compared as equal according to the type's default btree opclass.
Concurrent matview refresh was modified to use the new operators
to solve these problems.

Documentation was added for record comparison, both for the
default btree operator class for record, and the newly added
operators.  Regression tests now check for proper behavior both
for a matview with a box column and a matview containing a citext
column.

Reviewed by Steve Singer, who suggested some of the doc language.
2013-10-09 14:26:09 -05:00
Bruce Momjian 9af4159fce pgindent run for release 9.3
This is the first run of the Perl-based pgindent script.  Also update
pgindent instructions.
2013-05-29 16:58:43 -04:00
Andrew Dunstan a570c98d7f Add new JSON processing functions and parser API.
The JSON parser is converted into a recursive descent parser, and
exposed for use by other modules such as extensions. The API provides
hooks for all the significant parser event such as the beginning and end
of objects and arrays, and providing functions to handle these hooks
allows for fairly simple construction of a wide variety of JSON
processing functions. A set of new basic processing functions and
operators is also added, which use this API, including operations to
extract array elements, object fields, get the length of arrays and the
set of keys of a field, deconstruct an object into a set of key/value
pairs, and create records from JSON objects and arrays of objects.

Catalog version bumped.

Andrew Dunstan, with some documentation assistance from Merlin Moncure.
2013-03-29 14:12:13 -04:00
Heikki Linnakangas 59d0bf9dca Add cost estimation of range @> and <@ operators.
The estimates are based on the existing lower bound histogram, and a new
histogram of range lengths.

Bump catversion, because the range length histogram now needs to be present
in statistic slot kind 6, or you get an error on @> and <@ queries. (A
re-ANALYZE would be enough to fix that, though)

Alexander Korotkov, with some refactoring by me.
2013-03-14 15:36:56 +02:00
Bruce Momjian bd61a623ac Update copyrights for 2013
Fully update git head, and update back branches in ./COPYRIGHT and
legal.sgml files.
2013-01-01 17:15:01 -05:00
Robert Haas c504513f83 Adjust many backend functions to return OID rather than void.
Extracted from a larger patch by Dimitri Fontaine.  It is hoped that
this will provide infrastructure for enriching the new event trigger
functionality, but it seems possibly useful for other purposes as
well.
2012-12-23 18:37:58 -05:00
Heikki Linnakangas 918eee0c49 Collect and use histograms of lower and upper bounds for range types.
This enables selectivity estimation of the <<, >>, &<, &> and && operators,
as well as the normal inequality operators: <, <=, >=, >. "range @> element"
is also supported, but the range-variant @> and <@ operators are not,
because they cannot be sensibly estimated with lower and upper bound
histograms alone. We would need to make some assumption about the lengths of
the ranges for that. Alexander's patch included a separate histogram of
lengths for that, but I left that out of the patch for simplicity. Hopefully
that will be added as a followup patch.

The fraction of empty ranges is also calculated and used in estimation.

Alexander Korotkov, heavily modified by me.
2012-08-27 15:58:46 +03:00
Bruce Momjian 927d61eeff Run pgindent on 9.2 source tree in preparation for first 9.3
commit-fest.
2012-06-10 15:20:04 -04:00
Tom Lane 0e5e167aae Collect and use element-frequency statistics for arrays.
This patch improves selectivity estimation for the array <@, &&, and @>
(containment and overlaps) operators.  It enables collection of statistics
about individual array element values by ANALYZE, and introduces
operator-specific estimators that use these stats.  In addition,
ScalarArrayOpExpr constructs of the forms "const = ANY/ALL (array_column)"
and "const <> ANY/ALL (array_column)" are estimated by treating them as
variants of the containment operators.

Since we still collect scalar-style stats about the array values as a
whole, the pg_stats view is expanded to show both these stats and the
array-style stats in separate columns.  This creates an incompatible change
in how stats for tsvector columns are displayed in pg_stats: the stats
about lexemes are now displayed in the array-related columns instead of the
original scalar-related columns.

There are a few loose ends here, notably that it'd be nice to be able to
suppress either the scalar-style stats or the array-element stats for
columns for which they're not useful.  But the patch is in good enough
shape to commit for wider testing.

Alexander Korotkov, reviewed by Noah Misch and Nathan Boley
2012-03-03 20:20:57 -05:00
Robert Haas cc53a1e7cc Add bitwise AND, OR, and NOT operators for macaddr data type.
Brendan Jurd, reviewed by Fujii Masao
2012-01-19 15:25:14 -05:00
Bruce Momjian e126958c2e Update copyright notices for year 2012. 2012-01-01 18:01:58 -05:00
Tom Lane a4ffcc8e11 More code review for rangetypes patch.
Fix up some infelicitous coding in DefineRange, and add some missing error
checks.  Rearrange operator strategy number assignments for GiST anyrange
opclass so that they don't make such a mess of opr_sanity's table of
operator names associated with different strategy numbers.  Assign
hopefully-temporary selectivity estimators to range operators that didn't
have one --- poor as the estimates are, they're still a lot better than the
default 0.5 estimate, and they'll shut up the opr_sanity test that wants to
see selectivity estimators on all built-in operators.
2011-11-21 16:19:53 -05:00
Tom Lane 709aca5960 Declare range inclusion operators as taking anyelement not anynonarray.
Use of anynonarray was a crude hack to get around ambiguity versus the
array inclusion operators of the same names.  My previous patch to extend
the parser's type resolution heuristics makes that unnecessary, so use
the more general declaration instead.  This eliminates a wart that these
operators couldn't be used with ranges over arrays, which are otherwise
supported just fine.

Also, mark range_before and range_after as commutator operators,
per discussion with Jeff Davis.
2011-11-17 18:56:33 -05:00
Tom Lane 4509033a00 Code review for range-types catalog entries.
Fix assorted infelicities, such as dependency on OIDs that aren't
hardwired, as well as outright misdeclaration of daterange_canonical(),
which resulted in crashes if you invoked it directly.  Add some more
regression tests to try to catch similar mistakes in future.
2011-11-16 18:21:34 -05:00
Heikki Linnakangas 4429f6a9e3 Support range data types.
Selectivity estimation functions are missing for some range type operators,
which is a TODO.

Jeff Davis
2011-11-03 13:42:15 +02:00
Tom Lane ea8e42f3a0 Fix failure to check whether a rowtype's component types are sortable.
The existence of a btree opclass accepting composite types caused us to
assume that every composite type is sortable.  This isn't true of course;
we need to check if the column types are all sortable.  There was logic
for this for the case of array comparison (ie, check that the element
type is sortable), but we missed the point for rowtypes.  Per Teodor's
report of an ANALYZE failure for an unsortable composite type.

Rather than just add some more ad-hoc logic for this, I moved knowledge of
the issue into typcache.c.  The typcache will now only report out array_eq,
record_cmp, and friends as usable operators if the array or composite type
will work with those functions.

Unfortunately we don't have enough info to do this for anonymous RECORD
types; in that case, just assume it will work, and take the runtime failure
as before if it doesn't.

This patch might be a candidate for back-patching at some point, but
given the lack of complaints from the field, I'd rather just test it in
HEAD for now.

Note: most of the places touched in this patch will need further work
when we get around to supporting hashing of record types.
2011-06-03 15:39:17 -04:00
Bruce Momjian bf50caf105 pgindent run before PG 9.1 beta 1. 2011-04-10 11:42:00 -04:00
Tom Lane 908ab80286 Further refine patch for commenting operator implementation functions.
Instead of manually maintaining the "implementation of XXX operator"
comments in pg_proc.h, delete all those entries and let initdb create
them via a join.  To let initdb figure out which name to use when there
is a conflict, change the comments for deprecated operators to say they
are deprecated --- which seems like a good thing to do anyway.
2011-03-03 15:55:47 -05:00
Tom Lane 94133a9354 Mark operator implementation functions as such in their comments.
Historically, we've not had separate comments for built-in pg_operator
entries, but relied on the comments for the underlying functions.  The
trouble with this approach is that there isn't much of anything to suggest
to users that they'd be better off using the operators instead.  So, move
all the relevant comments into pg_operator, and give each underlying
function a comment that just says "implementation of XXX operator".
There are only about half a dozen cases where it seems reasonable to use
the underlying function interchangeably with the operator; in these cases
I left the same comment in place on the function as on the operator.

While at it, establish a policy that every built-in function and operator
entry should have a comment: there are now queries in the opr_sanity
regression test that will complain if one doesn't.  This only required
adding a dozen or two more entries than would have been there anyway.

I also spent some time trying to eliminate gratuitous inconsistencies in
the style of the comments, though it's hopeless to suppose that more won't
creep in soon enough.

Per my proposal of 2010-10-15.
2011-03-03 01:34:17 -05:00
Bruce Momjian 5d950e3b0c Stamp copyrights for year 2011. 2011-01-01 13:18:15 -05:00
Tom Lane 186cbbda8f Provide hashing support for arrays.
The core of this patch is hash_array() and associated typcache
infrastructure, which works just about exactly like the existing support
for array comparison.

In addition I did some work to ensure that the planner won't think that an
array type is hashable unless its element type is hashable, and similarly
for sorting.  This includes adding a datatype parameter to op_hashjoinable
and op_mergejoinable, and adding an explicit "hashable" flag to
SortGroupClause.  The lack of a cross-check on the element type was a
pre-existing bug in mergejoin support --- but it didn't matter so much
before, because if you couldn't sort the element type there wasn't any good
alternative to failing anyhow.  Now that we have the alternative of hashing
the array type, there are cases where we can avoid a failure by being picky
at the planner stage, so it's time to be picky.

The issue of exactly how to combine the per-element hash values to produce
an array hash is still open for discussion, but the rest of this is pretty
solid, so I'll commit it as-is.
2010-10-30 21:56:11 -04:00