planner: fix the case that projection prunes all columns

pkg/planner/core/casetest/hint/testdata/integration_suite_out.json

@@ -799,16 +799,13 @@
           "HashAgg 16000.00 root  group by:Column#41, funcs:firstrow(Column#41)->Column#41",
           "└─Union 1000000010000.00 root  ",
           "  ├─HashJoin 1000000000000.00 root  CARTESIAN inner join",
-          "  │ ├─TableReader(Build) 10000.00 root  data:TableFullScan",
-          "  │ │ └─TableFullScan 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo",
-          "  │ └─Projection(Probe) 100000000.00 root  1->Column#55",
-          "  │   └─HashJoin 100000000.00 root  CARTESIAN inner join",
-          "  │     ├─Projection(Build) 10000.00 root  1->Column#54",
-          "  │     │ └─IndexReader 10000.00 root  index:IndexFullScan",
-          "  │     │   └─IndexFullScan 10000.00 cop[tikv] table:t3, index:idx_a(a) keep order:false, stats:pseudo",
-          "  │     └─Projection(Probe) 10000.00 root  1->Column#53",
-          "  │       └─IndexReader 10000.00 root  index:IndexFullScan",
-          "  │         └─IndexFullScan 10000.00 cop[tikv] table:t2, index:idx_a(a) keep order:false, stats:pseudo",
+          "  │ ├─IndexReader(Build) 10000.00 root  index:IndexFullScan",
+          "  │ │ └─IndexFullScan 10000.00 cop[tikv] table:t3, index:idx_a(a) keep order:false, stats:pseudo",
+          "  │ └─HashJoin(Probe) 100000000.00 root  CARTESIAN inner join",
+          "  │   ├─IndexReader(Build) 10000.00 root  index:IndexFullScan",
+          "  │   │ └─IndexFullScan 10000.00 cop[tikv] table:t2, index:idx_a(a) keep order:false, stats:pseudo",
+          "  │   └─TableReader(Probe) 10000.00 root  data:TableFullScan",
+          "  │     └─TableFullScan 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo",
           "  └─TableReader 10000.00 root  data:TableFullScan",
           "    └─TableFullScan 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo"
         ],

pkg/planner/core/casetest/physicalplantest/testdata/plan_suite_out.json

@@ -3455,11 +3455,12 @@
           "└─TableReader 1.00 root  MppVersion: 2, data:ExchangeSender",
           "  └─ExchangeSender 1.00 mpp[tiflash]  ExchangeType: PassThrough",
           "    └─HashAgg 1.00 mpp[tiflash]  funcs:count(1)->Column#20",
-          "      └─HashJoin 12500.00 mpp[tiflash]  inner join, equal:[eq(test.t.a, test.t.e)]",
-          "        ├─ExchangeReceiver(Build) 10000.00 mpp[tiflash]  ",
-          "        │ └─ExchangeSender 10000.00 mpp[tiflash]  ExchangeType: Broadcast, Compression: FAST",
-          "        │   └─TableFullScan 10000.00 mpp[tiflash] table:t1 keep order:false, stats:pseudo",
-          "        └─TableFullScan(Probe) 10000.00 mpp[tiflash] table:t2 keep order:false, stats:pseudo"
+          "      └─Projection 12500.00 mpp[tiflash]  test.t.a",
+          "        └─HashJoin 12500.00 mpp[tiflash]  inner join, equal:[eq(test.t.a, test.t.e)]",
+          "          ├─ExchangeReceiver(Build) 10000.00 mpp[tiflash]  ",
+          "          │ └─ExchangeSender 10000.00 mpp[tiflash]  ExchangeType: Broadcast, Compression: FAST",
+          "          │   └─TableFullScan 10000.00 mpp[tiflash] table:t1 keep order:false, stats:pseudo",
+          "          └─TableFullScan(Probe) 10000.00 mpp[tiflash] table:t2 keep order:false, stats:pseudo"
         ],
         "Warning": null
       },

pkg/planner/core/logical_projection.go

@@ -132,6 +132,10 @@ func (p *LogicalProjection) PruneColumns(parentUsedCols []*expression.Column, op
 	if err != nil {
 		return nil, err
 	}
+	// If its columns are all pruned, we directly use its child. The child will output at least one column.
+	if p.Schema().Len() == 0 {
+		return p.Children()[0], nil
+	}
 	return p, nil
 }
 

pkg/planner/core/operator/logicalop/logical_schema_producer.go

@@ -15,6 +15,8 @@
 package logicalop
 
 import (
+	"math"
+
 	"github.com/pingcap/tidb/pkg/expression"
 	"github.com/pingcap/tidb/pkg/planner/util/optimizetrace"
 	"github.com/pingcap/tidb/pkg/planner/util/optimizetrace/logicaltrace"
@@ -70,11 +72,23 @@ func (s *LogicalSchemaProducer) SetSchemaAndNames(schema *expression.Schema, nam
 
 // InlineProjection prunes unneeded columns inline an executor.
 func (s *LogicalSchemaProducer) InlineProjection(parentUsedCols []*expression.Column, opt *optimizetrace.LogicalOptimizeOp) {
-	if len(parentUsedCols) == 0 {
-		return
-	}
 	prunedColumns := make([]*expression.Column, 0)
 	used := expression.GetUsedList(s.SCtx().GetExprCtx().GetEvalCtx(), parentUsedCols, s.Schema())
+	if len(parentUsedCols) == 0 {
+		minColLen := math.MaxInt
+		chosenPos := 0
+		for i, col := range s.schema.Columns {
+			flen := col.GetType(s.SCtx().GetExprCtx().GetEvalCtx()).GetFlen()
+			if flen < minColLen {
+				chosenPos = i
+				minColLen = flen
+			}
+		}
+		// It chould be always true.
+		if len(used) > 0 {
+			used[chosenPos] = true
+		}
+	}
 	for i := len(used) - 1; i >= 0; i-- {
 		if !used[i] {
 			prunedColumns = append(prunedColumns, s.Schema().Columns[i])

tests/integrationtest/r/planner/core/casetest/integration.result

@@ -376,9 +376,8 @@ id	estRows	task	access object	operator info
 HashJoin	10000.00	root		CARTESIAN left outer semi join, other cond:eq(2, planner__core__casetest__integration.t.b)
 ├─TableReader(Build)	10000.00	root		data:TableFullScan
 │ └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
-└─Projection(Probe)	10000.00	root		1->Column#22
-  └─TableReader	10000.00	root		data:TableFullScan
-    └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
+└─TableReader(Probe)	10000.00	root		data:TableFullScan
+  └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
 select (2) in (select b from t) from (select t.a < (select t.a from t t1 limit 1) from t) t;
 (2) in (select b from t)
 1

tests/integrationtest/r/planner/core/issuetest/planner_issue.result

@@ -552,3 +552,93 @@ drop view if exists v0;
 CREATE VIEW v0(c0) AS SELECT t0.c0 FROM t0;
 SELECT t0.c0 FROM v0, t0 LEFT JOIN t1 ON t0.c0 WHERE ((INET_ATON('5V')) IS NULL);
 c0
+CREATE TABLE `t31cdd702` (
+`col_48` date NOT NULL DEFAULT '2003-04-01',
+`col_49` time NOT NULL,
+`col_50` text DEFAULT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=gbk COLLATE=gbk_chinese_ci;
+INSERT INTO `t31cdd702` VALUES('1976-03-13','02:40:13',''),('2007-07-19','02:40:13',''),('2000-03-19','02:40:13',''),('1970-04-16','02:40:13',''),('2024-06-23','02:40:13',''),('2022-01-22','02:40:13',''),('2017-04-12','02:40:13',''),('1998-08-10','02:40:13',''),('2025-12-28','02:40:13',''),('2001-01-14','02:40:13',''),('1997-12-10','02:40:13',''),('2014-01-15','02:40:13',''),('1992-04-21','07:55:36','&v'),('2024-05-15','02:40:13',''),('1978-08-28','02:40:13',''),('2030-01-07','02:40:13',''),('1981-10-26','02:40:13',''),('1988-02-10','02:40:13',''),('2016-02-14','02:40:13',''),('1996-11-21','09:54:04','on6VRKYtaI'),('2022-08-03','02:40:13',''),('2034-10-05','02:40:13',''),('1988-11-12','02:18:22','m'),('2028-04-17','02:40:13',''),('1993-08-30','07:32:34','f@C*'),('2002-11-22','02:40:13',''),('2016-11-13','02:40:13',''),('2018-08-02','02:40:13',''),('1973-07-30','02:40:13',''),('2014-12-28','02:40:13',''),('1978-05-07','02:40:13',''),('1992-05-07','08:05:41','9'),('1979-05-23','04:08:58','brm'),('1996-08-01','23:10:58','IyG643!'),('2034-05-31','04:48:28',''),('1978-08-10','20:38:16','_$8reH*!MLE43'),('1986-08-13','23:20:51','eHr%WCBu');
+CREATE TABLE `tl45f49bec` (
+`col_21` time NOT NULL DEFAULT '19:03:14',
+`col_22` text COLLATE gbk_bin NOT NULL,
+`col_23` float NOT NULL,
+PRIMARY KEY (`col_22`(2),`col_21`,`col_23`) /*T![clustered_index] CLUSTERED */,
+UNIQUE KEY `idx_4` (`col_22`(1),`col_21`)
+) ENGINE=InnoDB DEFAULT CHARSET=gbk COLLATE=gbk_bin;
+INSERT INTO `tl45f49bec` VALUES('05:26:53','',6436.3984),('05:33:06','',2418.3447),('05:56:03','!34',5327.29),('11:11:13','$uX7jK=*(prX#fm',8447.91),('05:35:17','*Jqx7z%a9~1Xw',7480.8096),('22:48:06','-',4563.9565),('03:48:30','1*t@',282.95325),('19:34:18','1~4i@f8X&exNs+CG0x',1238.2216),('13:22:26','3c9iE',1337.3021),('11:30:51','4xyKNd7+tKbh',130.22589),('22:35:40','56vCiz^%#hcS',8593.311),('07:56:40','5W0p%FB$cMOcC_-37k',7798.0645),('23:17:09','6A!03oVaCmLM',6335.1514),('04:29:52','7N',8081.281),('04:14:22','7rW*b',2108.5618),('02:11:20','87O8gvnLG5',5109.0845),('11:43:02','=0vROyDng',9798.294),('06:21:18','@+0~@GdUE%+hSJg*#',7182.4136),('03:08:56','B1y^-u_v+l',2024.7775),('11:36:31','E#o%-MWl',3556.0056),('17:40:46','E1!qy4Qvw6s',8514.763),('13:40:54','IwMfmh$lfz',2577.1978),('00:55:17','J&eq%cQP+cx',1946.7703),('23:26:11','JJ0',9597.079),('19:16:32','K0VO3g(_nx%HMX',3434.9307),('14:35:00','LEJ9!B',1137.5157),('01:26:40','Sfuqtm',5829.2686),('11:58:06','XpqXa^b*%b!&I4ZnS',5890.494),('21:06:51','^',6630.6665),('03:22:56','^a',9613.8545),('04:30:59','_bmnB!IeDpljq',6335.3916),('08:29:45','b)=RH&R',5911.286),('18:56:18','h+5l9',1037.6467),('22:44:14','sZuxMLWUU',5482.626),('03:51:42','x-7',9611.379);
+SELECT 1 AS `r0` FROM (`t31cdd702`) JOIN `tl45f49bec` WHERE `tl45f49bec`.`col_22` BETWEEN 'LEJ9!B' AND 'TV#~!yw' LIMIT 24622829;
+r0
+1
+1
+1
+1
+1
+1
+1
+1
+1
+1
+1
+1
+1
+1
+1
+1
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+1
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+1
+1
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+1
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+1
+1
+1
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+1
+1
+1
+1
+1

tests/integrationtest/t/planner/core/issuetest/planner_issue.test

@@ -414,3 +414,24 @@ drop view if exists v0;
 CREATE VIEW v0(c0) AS SELECT t0.c0 FROM t0;
 
 SELECT t0.c0 FROM v0, t0 LEFT JOIN t1 ON t0.c0 WHERE ((INET_ATON('5V')) IS NULL);
+
+# https://github.com/pingcap/tidb/issues/54648
+CREATE TABLE `t31cdd702` (
+  `col_48` date NOT NULL DEFAULT '2003-04-01',
+  `col_49` time NOT NULL,
+  `col_50` text DEFAULT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=gbk COLLATE=gbk_chinese_ci;
+
+INSERT INTO `t31cdd702` VALUES('1976-03-13','02:40:13',''),('2007-07-19','02:40:13',''),('2000-03-19','02:40:13',''),('1970-04-16','02:40:13',''),('2024-06-23','02:40:13',''),('2022-01-22','02:40:13',''),('2017-04-12','02:40:13',''),('1998-08-10','02:40:13',''),('2025-12-28','02:40:13',''),('2001-01-14','02:40:13',''),('1997-12-10','02:40:13',''),('2014-01-15','02:40:13',''),('1992-04-21','07:55:36','&v'),('2024-05-15','02:40:13',''),('1978-08-28','02:40:13',''),('2030-01-07','02:40:13',''),('1981-10-26','02:40:13',''),('1988-02-10','02:40:13',''),('2016-02-14','02:40:13',''),('1996-11-21','09:54:04','on6VRKYtaI'),('2022-08-03','02:40:13',''),('2034-10-05','02:40:13',''),('1988-11-12','02:18:22','m'),('2028-04-17','02:40:13',''),('1993-08-30','07:32:34','f@C*'),('2002-11-22','02:40:13',''),('2016-11-13','02:40:13',''),('2018-08-02','02:40:13',''),('1973-07-30','02:40:13',''),('2014-12-28','02:40:13',''),('1978-05-07','02:40:13',''),('1992-05-07','08:05:41','9'),('1979-05-23','04:08:58','brm'),('1996-08-01','23:10:58','IyG643!'),('2034-05-31','04:48:28',''),('1978-08-10','20:38:16','_$8reH*!MLE43'),('1986-08-13','23:20:51','eHr%WCBu');
+
+CREATE TABLE `tl45f49bec` (
+  `col_21` time NOT NULL DEFAULT '19:03:14',
+  `col_22` text COLLATE gbk_bin NOT NULL,
+  `col_23` float NOT NULL,
+  PRIMARY KEY (`col_22`(2),`col_21`,`col_23`) /*T![clustered_index] CLUSTERED */,
+  UNIQUE KEY `idx_4` (`col_22`(1),`col_21`)
+) ENGINE=InnoDB DEFAULT CHARSET=gbk COLLATE=gbk_bin;
+
+INSERT INTO `tl45f49bec` VALUES('05:26:53','',6436.3984),('05:33:06','',2418.3447),('05:56:03','!34',5327.29),('11:11:13','$uX7jK=*(prX#fm',8447.91),('05:35:17','*Jqx7z%a9~1Xw',7480.8096),('22:48:06','-',4563.9565),('03:48:30','1*t@',282.95325),('19:34:18','1~4i@f8X&exNs+CG0x',1238.2216),('13:22:26','3c9iE',1337.3021),('11:30:51','4xyKNd7+tKbh',130.22589),('22:35:40','56vCiz^%#hcS',8593.311),('07:56:40','5W0p%FB$cMOcC_-37k',7798.0645),('23:17:09','6A!03oVaCmLM',6335.1514),('04:29:52','7N',8081.281),('04:14:22','7rW*b',2108.5618),('02:11:20','87O8gvnLG5',5109.0845),('11:43:02','=0vROyDng',9798.294),('06:21:18','@+0~@GdUE%+hSJg*#',7182.4136),('03:08:56','B1y^-u_v+l',2024.7775),('11:36:31','E#o%-MWl',3556.0056),('17:40:46','E1!qy4Qvw6s',8514.763),('13:40:54','IwMfmh$lfz',2577.1978),('00:55:17','J&eq%cQP+cx',1946.7703),('23:26:11','JJ0',9597.079),('19:16:32','K0VO3g(_nx%HMX',3434.9307),('14:35:00','LEJ9!B',1137.5157),('01:26:40','Sfuqtm',5829.2686),('11:58:06','XpqXa^b*%b!&I4ZnS',5890.494),('21:06:51','^',6630.6665),('03:22:56','^a',9613.8545),('04:30:59','_bmnB!IeDpljq',6335.3916),('08:29:45','b)=RH&R',5911.286),('18:56:18','h+5l9',1037.6467),('22:44:14','sZuxMLWUU',5482.626),('03:51:42','x-7',9611.379);
+
+SELECT 1 AS `r0` FROM (`t31cdd702`) JOIN `tl45f49bec` WHERE `tl45f49bec`.`col_22` BETWEEN 'LEJ9!B' AND 'TV#~!yw' LIMIT 24622829;