opt: infer equality filters for self joins

When a table is joined to itself with an equality that forms a key
over both join inputs, it is possible to infer equality filters
between each pair of columns at the same ordinal position in the base
table. This patch improves the logical props builder to infer these
self-join equalities in a join's FuncDepSet. This improves the quality
of information available to optimization rules, and in particular, join
elimination rules.

Informs cockroachdb#102614

Release note: None

pkg/sql/opt/exec/execbuilder/testdata/distsql_single_flow

@@ -1,16 +1,18 @@
 # LogicTest: 5node
 
 statement ok
-CREATE TABLE t (a INT PRIMARY KEY, b INT, c INT)
+CREATE TABLE t1 (a INT PRIMARY KEY, b INT, c INT);
+CREATE TABLE t2 (a INT PRIMARY KEY, b INT, c INT);
 
 # Move the single range to a remote node.
 statement ok
-ALTER TABLE t EXPERIMENTAL_RELOCATE VALUES (ARRAY[2], 2);
+ALTER TABLE t1 EXPERIMENTAL_RELOCATE VALUES (ARRAY[2], 2);
+ALTER TABLE t2 EXPERIMENTAL_RELOCATE VALUES (ARRAY[2], 2);
 
 # There are no stats on the table, so the single flow should stay on the remote
 # node.
 query T
-EXPLAIN (VEC) SELECT * FROM t AS t1, t AS t2 WHERE t1.a = t2.b
+EXPLAIN (VEC) SELECT * FROM t1, t2 WHERE t1.a = t2.b
 ----
 │
 ├ Node 1
@@ -22,7 +24,7 @@ EXPLAIN (VEC) SELECT * FROM t AS t1, t AS t2 WHERE t1.a = t2.b
       └ *colfetcher.ColBatchScan
 
 query T
-EXPLAIN (DISTSQL) SELECT * FROM t AS t1, t AS t2 WHERE t1.a = t2.b
+EXPLAIN (DISTSQL) SELECT * FROM t1, t2 WHERE t1.a = t2.b
 ----
 distribution: full
 vectorized: true
@@ -33,20 +35,42 @@ vectorized: true
 │
 ├── • scan
 │     missing stats
-│     table: t@t_pkey
+│     table: t1@t1_pkey
 │     spans: FULL SCAN
 │
 └── • scan
       missing stats
-      table: t@t_pkey
+      table: t2@t2_pkey
       spans: FULL SCAN
 ·
-Diagram: https://cockroachdb.github.io/distsqlplan/decode.html#eJysklFr2zAQx9_3KcQ9JUNpLDnbg6Dg0njUI026OLDBKEWxL4mpY3nSma6EfPdhp10T06TbmB6MdTr97v8_3QbcjxwUhN9uRhfRmHWGUTyLv4y6LA5H4eWMvWefppNrRuwiZiT4049kX6_CachInGl2zkiezYFDYVIc6zU6UN9BAAcJtxxKaxJ0ztg6vGmSovQnKI9DVpQV1eFbDomxCGoDlFGOoGBseqbs-8AhRdJZ3qRtOZiKXi450ksENdirEg1B-Vu-V0icLjTT8xynqFO0fe-gHFBAd-U9PgKHS5NX68Ippjmbc5YAh7jUdaAHx2SJlizvX2WJ_ypLtmSJo7Je1FSFsSlaTNvv8XbKK96utFt9NlmBti8PreW4oE4guuc2W66oE8gucJhUpFggeCB54PNgwIMPPPh41J_f8icP_L0xdlN0pSkc_tHcea1KPVG7xXSJu-45U9kEb6xJmtzddtKAmkCKjnang90mKp6PHFnU699Ts08SJ0n-AUmcJMm_IMl9kmiT_JMk77g7WXdskZuHuywFBd7T6r3yeV5QX9BLVz9bvDIPDXb2WNZNX-jcIYdrfY9DJLTrrMgcZQkoshVut-9-BQAA__9iPZLx
+Diagram: https://cockroachdb.github.io/distsqlplan/decode.html#eJykkt9v2jAQx9_3V1j3VKajxA7bg6VKmQpTmSh0gLRJU1WZ5ICoIc7si7oK8b9PCesKUaH74QdLPp8_9_2ebwP-ewYa-l9vhh8GI3HWG0xn08_Dlpj2h_3LmXgrPk7G14IlClbiy1V_0hcsz424EKzO54CQ24RGZk0e9DeQgKDgFqFwNibvravCmzppkPwAHSCkeVFyFb5FiK0j0BvglDMCDSPbtkUnBISE2KRZnbZFsCU_P_JslgS6u1dl0AMdbnGvkDxdaGbmGU3IJOQ6wUE5YBmxvCvu6REQLm1WrnOvhUExRxEDwrQwVaANx4TJhrDgX4XJhjAVsfofYaohTB4V9qynzK1LyFHS_JPXU15wd2X86pNNc3IddWguowWfRbJ14dLlis8i1QKEcclaRBIjhVGIURejdxi9P-ovbPhTB_5eGb0J-cLmnv5o9oJGpbas3FKypF33vC1dTDfOxnXu7jiuQXUgIc-72-7uMMifrjw7Muvfc7NPkidJ4QFJniSpvyCpfZJsksKTpOC4O1V1bJHZh7s0AQ3Br9V-YXtaUD0wS19923RlH2rs7LGomr4wmSeEa3NPPWJy6zRPPacxaHYlbbdvfgYAAP__MJ2RJw==
 
 # Inject stats so that column 'b' has few unique values whereas column 'c' has
 # many unique values.
 statement ok
-ALTER TABLE t INJECT STATISTICS '[
+ALTER TABLE t1 INJECT STATISTICS '[
+  {
+    "columns": ["a"],
+    "created_at": "2018-01-01 1:00:00.00000+00:00",
+    "row_count": 10000,
+    "distinct_count": 10000
+  },
+  {
+    "columns": ["b"],
+    "created_at": "2018-01-01 1:00:00.00000+00:00",
+    "row_count": 10000,
+    "distinct_count": 3
+  },
+  {
+    "columns": ["c"],
+    "created_at": "2018-01-01 1:00:00.00000+00:00",
+    "row_count": 10000,
+    "distinct_count": 100
+  }
+]'
+
+statement ok
+ALTER TABLE t2 INJECT STATISTICS '[
   {
     "columns": ["a"],
     "created_at": "2018-01-01 1:00:00.00000+00:00",
@@ -69,7 +93,7 @@ ALTER TABLE t INJECT STATISTICS '[
 
 # Now check that the single flow with a join is moved to the gateway.
 query T
-EXPLAIN (VEC) SELECT * FROM t AS t1, t AS t2 WHERE t1.a = t2.b
+EXPLAIN (VEC) SELECT * FROM t1, t2 WHERE t1.a = t2.b
 ----
 │
 └ Node 1
@@ -78,7 +102,7 @@ EXPLAIN (VEC) SELECT * FROM t AS t1, t AS t2 WHERE t1.a = t2.b
     └ *colfetcher.ColBatchScan
 
 query T
-EXPLAIN (DISTSQL) SELECT * FROM t AS t1, t AS t2 WHERE t1.a = t2.b
+EXPLAIN (DISTSQL) SELECT * FROM t1, t2 WHERE t1.a = t2.b
 ----
 distribution: local
 vectorized: true
@@ -90,20 +114,20 @@ vectorized: true
 │
 ├── • scan
 │     estimated row count: 10,000 (100% of the table; stats collected <hidden> ago)
-│     table: t@t_pkey
+│     table: t1@t1_pkey
 │     spans: FULL SCAN
 │
 └── • scan
       estimated row count: 10,000 (100% of the table; stats collected <hidden> ago)
-      table: t@t_pkey
+      table: t2@t2_pkey
       spans: FULL SCAN
 ·
-Diagram: https://cockroachdb.github.io/distsqlplan/decode.html#eJysktFr2zAQxt_3V4h7asaltZRtD4KCS5NRj7Tp4sAGwxTFviSmjuVJZ7oS8r8PO92amHSjY3ow1un0u-_70Ab89wI0jL7eji-iG3EyjOJZ_HncE_FoPLqcibfi43RyLVhcxIIlPv0o8eVqNB0JlqdGnAtWp3NAKG1GN2ZNHvQ3kJAgVM6m5L11TWnTNkTZD9ABQl5WNTflBCG1jkBvgHMuCDTMzLygKZmM3FkACBmxyYsWyyHfVff0CAiXtqjXpdfCoJijSAEhrkxT6EOyRbA1P4_wbJYEWu5pioaggy3-myz5X2Wpjiz5oqxnNXVpXUaOsgMlSXPzby1HvF0Zv_pk85LcmTq0VtCCT0LZO3f5csUnoeoBwqRmLUKJocJwgOE7DN9j-OFFf4OOP_Wa2KfkK1t66vo8OinoTOrLxi1lS9ql523tUrp1Nm17d9tJC2oLGXnenardJirbI9lMcGTWv1_NPkm-gqT2SbJLUn8kDQ5IwaGmBGFR2Ie7PAMNwdPqH_n8WtBcMEvfhB2v7EOLnT1WTVQLU3hCuDb3NCQmt87L3HOegmZX03b75mcAAAD__wrGV6A=
+Diagram: https://cockroachdb.github.io/distsqlplan/decode.html#eJykklFr2zAQx9_3KcQ9JePSWsq2B0FBo8loRtp0SWCDYYpiXxJTx_KkM10J-e7DzrYmJt3opgeDTtLvfv_DWwjfctAw_HI7fj-6EZ3BaDaffRp3xWw4Hl7OxWvxYTq5FixRsBKfr4bToWB5ZsWFYHW2AITCpXRjNxRAfwUJMULpXUIhOF-Xts2FUfoddISQFWXFdTlGSJwn0FvgjHMCDXO7yGlKNiV_HgFCSmyzvMGyNCzvynt6BIRLl1ebImhhUSxQJIAwK21d6EG8Q3AVPzUJbFcEWh5YjQagox3-m5hsiSnD6n_EVEtMPiv25FMVzqfkKT1yieuXf7tyIt2VDeuPLivIn6vjcDktuWNk98JnqzV3jOoCwqRiLYxEo9D00bxB8xbNu2fz9Vv51EsGP6VQuiJQO-fJTlGrU0_WaSld0X56wVU-oVvvkubufjtpQE0hpcD7U7XfjIrmSNYdPNnN7__mkCRfQFKHJNkmqT-S-kek6NgpRljm7uEuS0FD9HP1Tnx-Lagf2FWohz1bu4cGO38s61EtbR4I4dre04CY_CYrssBZApp9Rbvdqx8BAAD__-o0VdY=
 
 
 # If we add a not very selective filter, the flow is still moved to the gateway.
 query T
-EXPLAIN (VEC) SELECT * FROM t AS t1, t AS t2 WHERE t1.b = 1 AND t1.a = t2.a
+EXPLAIN (VEC) SELECT * FROM t1, t2 WHERE t1.b = 1 AND t1.a = t2.a
 ----
 │
 └ Node 1
@@ -113,7 +137,7 @@ EXPLAIN (VEC) SELECT * FROM t AS t1, t AS t2 WHERE t1.b = 1 AND t1.a = t2.a
       └ *colfetcher.ColBatchScan
 
 query T
-EXPLAIN (DISTSQL) SELECT * FROM t AS t1, t AS t2 WHERE t1.b = 1 AND t1.a = t2.a
+EXPLAIN (DISTSQL) SELECT * FROM t1, t2 WHERE t1.b = 1 AND t1.a = t2.a
 ----
 distribution: local
 vectorized: true
@@ -126,7 +150,7 @@ vectorized: true
 │
 ├── • scan
 │     estimated row count: 10,000 (100% of the table; stats collected <hidden> ago)
-│     table: t@t_pkey
+│     table: t2@t2_pkey
 │     spans: FULL SCAN
 │
 └── • filter
@@ -135,14 +159,14 @@ vectorized: true
     │
     └── • scan
           estimated row count: 10,000 (100% of the table; stats collected <hidden> ago)
-          table: t@t_pkey
+          table: t1@t1_pkey
           spans: FULL SCAN
 ·
-Diagram: https://cockroachdb.github.io/distsqlplan/decode.html#eJyskl9r2zAUxd_3KcR9ajalsWRnDEHAoUmZR_50cWCDEYpi36SmjuVJMl0J-e7DdrcmJsmWMT8Y6Ur6nXN0tQXzPQUBw693o34wIVeDIJyHn0ctEg5Hw5s5eUtuZ9MxsaQfEsvoy4CTLx-HsyG5sux6SXqEtUh_MqimkvSI5deyBRQyFeNEbtCA-AYMFhRyrSI0RumytK02BPEPEA6FJMsLW5YXFCKlEcQWbGJTBAFzuUxxhjJG3XGAQoxWJmmFtb69zx_xGSjcqLTYZEYQScmSkggohLksC21Y7Ciowr5KGCvXCILteQoGIJwd_Tdb7L_a4g1b7BJbt0lqUaPu8ENPdV0Qn5ctE0IEk_mHkxbchgV-0sKrcpEpHaPG-EB4UZ7805YjOcao1_hJJRnqjnsYJcWVvfLZu1ZPJ-uHeggUpoUVxPeo36X-e-oz6nPquycjeo2I7iW3PFFtlXe8ZtKjQt2GkHeJ0AxNrjKDf6XkNJTarLxZjNdYd8qoQkd4p1VU7a2n0wpUFWI0tl5160mQVUusVNAoN79f4z6JnSXxA5KzT3KaJH6BJ75P4k2Se5bknfbkNkneWVL3XLoFhVWqnu6TGAQ4L1_7yO_XB-UBuTblAwgf1FOFnT_nZftWMjVIYSwfcYAW9SbJEmOTCITVBe52b34GAAD__75k2MI=
+Diagram: https://cockroachdb.github.io/distsqlplan/decode.html#eJykkl9v2jAUxd_3Kaz7BJspsROmyRJSqkK1TPzpAGmTJlSZ5JJGDXFmO-oqxHefkmwrRMDG6ocovrZ_5xxfb8F8T0HA8Ovd6DqYkNYgmC_mn0dtMh-OhjcL8pbczqZjYhkllpMvH4ezIWlZdrUifcLa5HoyqKaS9InlV7INFDIV4URu0ID4BgyWFHKtQjRG6bK0rTYE0Q8QDoUkywtblpcUQqURxBZsYlMEAQu5SnGGMkLddYBChFYmaYW13Lf8Pn_EZ6Bwo9JikxlBJCUrSkKgMM9lWejAckdBFfZFxFgZIwi25yoYgHB29P-MsYYx5lv2GmO8YYxdYuw2SS1q1F1-6KquC-Lzsm1CiGCy-HDSgtuwwE9aeFEuMqUj1BgdCC_Lk3_bciTHGHWMn1SSoe66h1FSXNuWz961-zqJH-pfoDAtrCC-R_0e9d9Tn1GfU989GdFrRHQvueWJ6qi86zWTHhXqNYS8S4RmaHKVGfwnJaeh1GHlzWIUY90powod4p1WYbW3nk4rUFWI0Nh61a0nQVYtsVJBo9z8eY37JHaWxA9Izj7JaZL4BZ74Pok3Se5Zknfak9skeWdJvXPplhTWqXq6TyIQ4PwanSOf3wPKAzI25QOYP6inCrt4zsv2rWVqkMJYPuIALepNkiXGJiEIqwvc7d78DAAA___NVNb4
 
 # However, if we add a selective filter, the flow is kept on the remote node.
 query T
-EXPLAIN (VEC) SELECT * FROM t AS t1 INNER MERGE JOIN t AS t2 ON t1.a = t2.a WHERE t1.c = 1
+EXPLAIN (VEC) SELECT * FROM t1 INNER MERGE JOIN t2 ON t1.a = t2.a WHERE t1.c = 1
 ----
 │
 ├ Node 1
@@ -155,7 +179,7 @@ EXPLAIN (VEC) SELECT * FROM t AS t1 INNER MERGE JOIN t AS t2 ON t1.a = t2.a WHER
       └ *colfetcher.ColBatchScan
 
 query T
-EXPLAIN (DISTSQL) SELECT * FROM t AS t1 INNER MERGE JOIN t AS t2 ON t1.a = t2.a WHERE t1.c = 1
+EXPLAIN (DISTSQL) SELECT * FROM t1 INNER MERGE JOIN t2 ON t1.a = t2.a WHERE t1.c = 1
 ----
 distribution: full
 vectorized: true
@@ -172,12 +196,12 @@ vectorized: true
 │   │
 │   └── • scan
 │         estimated row count: 10,000 (100% of the table; stats collected <hidden> ago)
-│         table: t@t_pkey
+│         table: t1@t1_pkey
 │         spans: FULL SCAN
 │
 └── • scan
       estimated row count: 10,000 (100% of the table; stats collected <hidden> ago)
-      table: t@t_pkey
+      table: t2@t2_pkey
       spans: FULL SCAN
 ·
-Diagram: https://cockroachdb.github.io/distsqlplan/decode.html#eJysktFr2zAQxt_3V4h7ajelsWx3DEHBpXU3l8Tp7MAGoxTVvqSmjuVJMl0J-d-H7HZNTJMuY34I8afT777vfEvQP0vgEH6_Gp1GMTk4j9Jp-nV0SNJwFJ5NyXtykUzGxJDTlBhGojgOEzIOk88huZxE8dOBSyYxMexIkBNi3CNBvn0Jk9AqGTkhDChUMsdYLFAD_wFWcOGaQq1khlpLZeVlWxTlv4A7FIqqboyVrylkUiHwJZjClAgcYjmQ9dAHCjkaUZRt2YqCbMzLJW3EHIEfr3WJzoH7K7rWiO1uNBW3JSYoclRDZ6MdmMDc1Pf4CBTOZNksKs2JoOSWkgwopLWwwgC22WI9W84-ti6K0qBCNWSbnjqdk8CzU-ecR_H001YLbs8C-9fJuP91Ml7PlrvV1oubppIqR4V5fyXeLnkl2xjVHC9lUaEaepvZSpyZg4B9ODxRxfyu-wsUJo3hJGA0cGng0cCnwTENPm6N6PciehsR31j-BHUtK41_tf1Or9OA2cCYz7EboJaNyvBKyayt7V4nLagVctSmOz3uXqLq-UgbhWLxZ3fXSWwnyd2D5O4k-Rsktk5ifZK3B8ldJ7l9kr-T5GxP59nZz0r5cFPkwMF5egav_Dw_YC-IubYLkN7JhxY7fazt55uJUiOFsbjHczSoFkVVaFNkwI1qcLV69zsAAP__78Xc4A==
+Diagram: https://cockroachdb.github.io/distsqlplan/decode.html#eJykk1Fr2zAUhd_3K8R9ajelsWRnDEHAo3E3l8TpnMAGoxTVvklNHcuTZLoS8t-H7XVNTJMumx9CfHT13XOupTWYHzkICL5djT-GETkZhbP57Mv4lMyCcXA-J2_JRTydEMtIGEVBTCZB_Ckgl9MwIpaTaUQsO5NkSCw_k-Tr5yAOaiUhQ8KAQqFSjOQKDYjvUAscrimUWiVojNK1vG6KwvQnCIdCVpSVreVrConSCGINNrM5goBI9VTZ94BCilZmeVO2oaAq-7zJWLlEEIOtLuEIhLehW43Y4UZzeZtjjDJF3Xd22oFlvmU35T0-AoVzlVerwggiKbmlJAEKs1LWQg_2GWMdY84xxi6y3KJG3We7rlpdEN-t5y6ECKP5h70WeMcC-9fZ8M5suG_5_8zG7Rjje409-6kKpVPUmHaPxeslL6SboF7ipcoK1H13N12OC3vis3enQ50t79q_QGFaWUF8Rn1OfZf6HvUH1H-_N6LXiejuRHzlAsRoSlUY_Ksb4HQ69VgdGNMltgM0qtIJXmmVNLXt67QBNUKKxrarg_YlLJ6WjNUoV39O7zaJHSTxI0j8IMnbIbFtEuuS3CNIfJvEuyTvIMnZn86tZ7_I1cNNloIA5_fTe-Hn6YF6g1ya-gDM7tRDg50_lvXnW8jcIIWJvMcRWtSrrMiMzRIQVle42bz5FQAA__89HtsW

pkg/sql/opt/exec/execbuilder/testdata/join

@@ -939,32 +939,30 @@ vectorized: true
           spans: FULL SCAN
 
 query T
-EXPLAIN (VERBOSE) SELECT * FROM pkBAC AS l JOIN pkBAC AS r USING(a, b, c)
+EXPLAIN (VERBOSE) SELECT * FROM pkBAC AS l JOIN pkBAC AS r USING(a, b)
 ----
 distribution: local
 vectorized: true
 ·
 • project
-│ columns: (a, b, c, d, d)
+│ columns: (a, b, c, d, c, d)
 │
 └── • merge join (inner)
     │ columns: (a, b, c, d, a, b, c, d)
-    │ estimated row count: 1 (missing stats)
-    │ equality: (b, a, c) = (b, a, c)
-    │ left cols are key
-    │ right cols are key
-    │ merge ordering: +"(b=b)",+"(a=a)",+"(c=c)"
+    │ estimated row count: 100 (missing stats)
+    │ equality: (b, a) = (b, a)
+    │ merge ordering: +"(b=b)",+"(a=a)"
     │
     ├── • scan
     │     columns: (a, b, c, d)
-    │     ordering: +b,+a,+c
+    │     ordering: +b,+a
     │     estimated row count: 1,000 (missing stats)
     │     table: pkbac@pkbac_pkey
     │     spans: FULL SCAN
     │
     └── • scan
           columns: (a, b, c, d)
-          ordering: +b,+a,+c
+          ordering: +b,+a
           estimated row count: 1,000 (missing stats)
           table: pkbac@pkbac_pkey
           spans: FULL SCAN