Add a hash opclass for type "tid".

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

7 files changed, 23 insertions, 4 deletions

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 0e89b303650..588a110093a 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201812202
+#define CATALOG_VERSION_NO	201812301
 
 #endif
diff --git a/src/include/catalog/pg_amop.dat b/src/include/catalog/pg_amop.dat
index e689c9b160a..436f1bd0762 100644
--- a/src/include/catalog/pg_amop.dat
+++ b/src/include/catalog/pg_amop.dat
@@ -1013,6 +1013,10 @@
 { amopfamily => 'hash/cid_ops', amoplefttype => 'cid', amoprighttype => 'cid',
   amopstrategy => '1', amopopr => '=(cid,cid)', amopmethod => 'hash' },
 
+# tid_ops
+{ amopfamily => 'hash/tid_ops', amoplefttype => 'tid', amoprighttype => 'tid',
+  amopstrategy => '1', amopopr => '=(tid,tid)', amopmethod => 'hash' },
+
 # text_pattern_ops
 { amopfamily => 'hash/text_pattern_ops', amoplefttype => 'text',
   amoprighttype => 'text', amopstrategy => '1', amopopr => '=(text,text)',
diff --git a/src/include/catalog/pg_amproc.dat b/src/include/catalog/pg_amproc.dat
index bbcee26fa8b..8ddb6991121 100644
--- a/src/include/catalog/pg_amproc.dat
+++ b/src/include/catalog/pg_amproc.dat
@@ -340,6 +340,10 @@
   amprocrighttype => 'cid', amprocnum => '1', amproc => 'hashint4' },
 { amprocfamily => 'hash/cid_ops', amproclefttype => 'cid',
   amprocrighttype => 'cid', amprocnum => '2', amproc => 'hashint4extended' },
+{ amprocfamily => 'hash/tid_ops', amproclefttype => 'tid',
+  amprocrighttype => 'tid', amprocnum => '1', amproc => 'hashtid' },
+{ amprocfamily => 'hash/tid_ops', amproclefttype => 'tid',
+  amprocrighttype => 'tid', amprocnum => '2', amproc => 'hashtidextended' },
 { amprocfamily => 'hash/text_pattern_ops', amproclefttype => 'text',
   amprocrighttype => 'text', amprocnum => '1', amproc => 'hashtext' },
 { amprocfamily => 'hash/text_pattern_ops', amproclefttype => 'text',
diff --git a/src/include/catalog/pg_opclass.dat b/src/include/catalog/pg_opclass.dat
index 5178d04337f..c451d365a6f 100644
--- a/src/include/catalog/pg_opclass.dat
+++ b/src/include/catalog/pg_opclass.dat
@@ -167,6 +167,8 @@
   opcintype => 'xid' },
 { opcmethod => 'hash', opcname => 'cid_ops', opcfamily => 'hash/cid_ops',
   opcintype => 'cid' },
+{ opcmethod => 'hash', opcname => 'tid_ops', opcfamily => 'hash/tid_ops',
+  opcintype => 'tid' },
 { opcmethod => 'hash', opcname => 'text_pattern_ops',
   opcfamily => 'hash/text_pattern_ops', opcintype => 'text',
   opcdefault => 'f' },
diff --git a/src/include/catalog/pg_operator.dat b/src/include/catalog/pg_operator.dat
index 2abd5311c3e..e8452e10d21 100644
--- a/src/include/catalog/pg_operator.dat
+++ b/src/include/catalog/pg_operator.dat
@@ -204,9 +204,10 @@
   oprrest => 'eqsel', oprjoin => 'eqjoinsel' },
 
 { oid => '387', oid_symbol => 'TIDEqualOperator', descr => 'equal',
-  oprname => '=', oprcanmerge => 't', oprleft => 'tid', oprright => 'tid',
-  oprresult => 'bool', oprcom => '=(tid,tid)', oprnegate => '<>(tid,tid)',
-  oprcode => 'tideq', oprrest => 'eqsel', oprjoin => 'eqjoinsel' },
+  oprname => '=', oprcanmerge => 't', oprcanhash => 't', oprleft => 'tid',
+  oprright => 'tid', oprresult => 'bool', oprcom => '=(tid,tid)',
+  oprnegate => '<>(tid,tid)', oprcode => 'tideq', oprrest => 'eqsel',
+  oprjoin => 'eqjoinsel' },
 { oid => '402', descr => 'not equal',
   oprname => '<>', oprleft => 'tid', oprright => 'tid', oprresult => 'bool',
   oprcom => '<>(tid,tid)', oprnegate => '=(tid,tid)', oprcode => 'tidne',
diff --git a/src/include/catalog/pg_opfamily.dat b/src/include/catalog/pg_opfamily.dat
index fe8a32485f2..c5ea37b5cd7 100644
--- a/src/include/catalog/pg_opfamily.dat
+++ b/src/include/catalog/pg_opfamily.dat
@@ -112,6 +112,8 @@
   opfmethod => 'hash', opfname => 'xid_ops' },
 { oid => '2226',
   opfmethod => 'hash', opfname => 'cid_ops' },
+{ oid => '2227',
+  opfmethod => 'hash', opfname => 'tid_ops' },
 { oid => '2229',
   opfmethod => 'hash', opfname => 'text_pattern_ops' },
 { oid => '2231',
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index acb0154048a..6e1e1dfad71 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -2484,6 +2484,12 @@
 { oid => '2796', descr => 'smaller of two',
   proname => 'tidsmaller', prorettype => 'tid', proargtypes => 'tid tid',
   prosrc => 'tidsmaller' },
+{ oid => '2233', descr => 'hash',
+  proname => 'hashtid', prorettype => 'int4', proargtypes => 'tid',
+  prosrc => 'hashtid' },
+{ oid => '2234', descr => 'hash',
+  proname => 'hashtidextended', prorettype => 'int8', proargtypes => 'tid int8',
+  prosrc => 'hashtidextended' },
 
 { oid => '1296',
   proname => 'timedate_pl', prolang => '14', prorettype => 'timestamp',