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[release-22.0] Fix column offset tracking for UNIONs to be case insensitive. (#19139) #19161

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Merged
arthurschreiber merged 2 commits into from
Jan 16, 2026
Merged

[release-22.0] Fix column offset tracking for UNIONs to be case insensitive. (#19139) #19161

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a947db5
Cherry-pick 421111452d002919e46f28f4322efc760807d054 with conflicts
vitess-bot[bot] Jan 16, 2026
9ea7582
Fix conflicts.
arthurschreiber Jan 16, 2026
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34 changes: 16 additions & 18 deletions go/vt/vtgate/planbuilder/operators/union.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ package operators
import (
"fmt"
"slices"
"strings"

"vitess.io/vitess/go/slice"
"vitess.io/vitess/go/vt/sqlparser"
Expand Down Expand Up @@ -101,42 +102,39 @@ func (u *Union) AddPredicate(ctx *plancontext.PlanningContext, expr sqlparser.Ex
if !ok {
panic(vterrors.VT12001("pushing predicates on UNION where the first SELECT contains * or NEXT"))
}
offsets[ae.ColumnName()] = i
}

if jp, ok := expr.(*predicates.JoinPredicate); ok {
expr = jp.Current()
ctx.PredTracker.Skip(jp.ID)
}

needsFilter, exprPerSource := u.predicatePerSource(expr, offsets)
if needsFilter {
return newFilter(u, expr)
offsets[strings.ToLower(ae.ColumnName())] = i
}

exprPerSource := u.predicatePerSource(ctx, expr, offsets)
for i, src := range u.Sources {
u.Sources[i] = src.AddPredicate(ctx, exprPerSource[i])
}

return u
}

func (u *Union) predicatePerSource(expr sqlparser.Expr, offsets map[string]int) (bool, []sqlparser.Expr) {
needsFilter := false
func (u *Union) predicatePerSource(ctx *plancontext.PlanningContext, expr sqlparser.Expr, offsets map[string]int) []sqlparser.Expr {
exprPerSource := make([]sqlparser.Expr, len(u.Sources))

for i := range u.Sources {
predicate := sqlparser.CopyOnRewrite(expr, nil, func(cursor *sqlparser.CopyOnWriteCursor) {
predicate := expr

if jp, ok := predicate.(*predicates.JoinPredicate); ok {
// Create a new JoinPredicate for each source to keep tracking working
// We can't use `*JoinPredicate.Clone` here as that would update the tracker and overwrite
// the expression for the original predicate
predicate = ctx.PredTracker.NewJoinPredicate(jp.Current())
}

predicate = sqlparser.CopyOnRewrite(predicate, nil, func(cursor *sqlparser.CopyOnWriteCursor) {
col, ok := cursor.Node().(*sqlparser.ColName)
if !ok {
return
}

idx, ok := offsets[col.Name.Lowered()]
if !ok {
needsFilter = true
cursor.StopTreeWalk()
return
panic(vterrors.VT13001(fmt.Sprintf("could not find the column '%s' on the UNION", sqlparser.String(col))))
}

sel := u.GetSelectFor(i)
Expand All @@ -151,7 +149,7 @@ func (u *Union) predicatePerSource(expr sqlparser.Expr, offsets map[string]int)
exprPerSource[i] = predicate
}

return needsFilter, exprPerSource
return exprPerSource
}

func (u *Union) GetSelectFor(source int) *sqlparser.Select {
Expand Down
150 changes: 69 additions & 81 deletions go/vt/vtgate/planbuilder/testdata/union_cases.json
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Original file line number Diff line number Diff line change
Expand Up @@ -1357,45 +1357,39 @@
"QueryType": "SELECT",
"Original": "select * from (select kcu.`COLUMN_NAME` from `information_schema`.`key_column_usage` `kcu` where `kcu`.`table_schema` = 'user' and `kcu`.`table_name` = 'user_extra' union select kcu.`COLUMN_NAME` from `information_schema`.`key_column_usage` `kcu` where `kcu`.`table_schema` = 'user' and `kcu`.`table_name` = 'music') `kcu` where `COLUMN_NAME` = 'primary'",
"Instructions": {
"OperatorType": "Filter",
"Predicate": "`COLUMN_NAME` = 'primary'",
"OperatorType": "Distinct",
"Collations": [
"0: utf8mb3_general_ci"
],
"Inputs": [
{
"OperatorType": "Distinct",
"Collations": [
"0: utf8mb3_general_ci"
],
"OperatorType": "Concatenate",
"Inputs": [
{
"OperatorType": "Concatenate",
"Inputs": [
{
"OperatorType": "Route",
"Variant": "DBA",
"Keyspace": {
"Name": "main",
"Sharded": false
},
"FieldQuery": "select kcu.`COLUMN_NAME` from information_schema.key_column_usage as kcu where 1 != 1",
"Query": "select distinct kcu.`COLUMN_NAME` from information_schema.key_column_usage as kcu where kcu.table_schema = :__vtschemaname /* VARCHAR */ and kcu.`table_name` = :kcu_table_name /* VARCHAR */",
"SysTableTableName": "[kcu_table_name:'user_extra']",
"SysTableTableSchema": "['user']",
"Table": "information_schema.key_column_usage"
},
{
"OperatorType": "Route",
"Variant": "DBA",
"Keyspace": {
"Name": "main",
"Sharded": false
},
"FieldQuery": "select kcu.`COLUMN_NAME` from information_schema.key_column_usage as kcu where 1 != 1",
"Query": "select distinct kcu.`COLUMN_NAME` from information_schema.key_column_usage as kcu where kcu.table_schema = :__vtschemaname /* VARCHAR */ and kcu.`table_name` = :kcu_table_name1 /* VARCHAR */",
"SysTableTableName": "[kcu_table_name1:'music']",
"SysTableTableSchema": "['user']",
"Table": "information_schema.key_column_usage"
}
]
"OperatorType": "Route",
"Variant": "DBA",
"Keyspace": {
"Name": "main",
"Sharded": false
},
"FieldQuery": "select kcu.`COLUMN_NAME` from information_schema.key_column_usage as kcu where 1 != 1",
"Query": "select distinct kcu.`COLUMN_NAME` from information_schema.key_column_usage as kcu where kcu.table_schema = :__vtschemaname /* VARCHAR */ and kcu.`table_name` = :kcu_table_name /* VARCHAR */ and `COLUMN_NAME` = 'primary'",
"SysTableTableName": "[kcu_table_name:'user_extra']",
"SysTableTableSchema": "['user']",
"Table": "information_schema.key_column_usage"
},
{
"OperatorType": "Route",
"Variant": "DBA",
"Keyspace": {
"Name": "main",
"Sharded": false
},
"FieldQuery": "select kcu.`COLUMN_NAME` from information_schema.key_column_usage as kcu where 1 != 1",
"Query": "select distinct kcu.`COLUMN_NAME` from information_schema.key_column_usage as kcu where kcu.table_schema = :__vtschemaname /* VARCHAR */ and kcu.`table_name` = :kcu_table_name1 /* VARCHAR */ and `COLUMN_NAME` = 'primary'",
"SysTableTableName": "[kcu_table_name1:'music']",
"SysTableTableSchema": "['user']",
"Table": "information_schema.key_column_usage"
}
]
}
Expand Down Expand Up @@ -1439,56 +1433,50 @@
"QueryType": "SELECT",
"Original": "select * from (select * from `information_schema`.`key_column_usage` `kcu` where `kcu`.`table_schema` = 'user' and `kcu`.`table_name` = 'user_extra' union select * from `information_schema`.`key_column_usage` `kcu` where `kcu`.`table_schema` = 'user' and `kcu`.`table_name` = 'music') `kcu` where `constraint_name` = 'primary'",
"Instructions": {
"OperatorType": "Filter",
"Predicate": "`constraint_name` = 'primary'",
"OperatorType": "Distinct",
"Collations": [
"0: utf8mb3_general_ci",
"1: utf8mb3_general_ci",
"2: utf8mb3_general_ci",
"3: utf8mb3_general_ci",
"4: utf8mb3_general_ci",
"5: utf8mb3_general_ci",
"6: utf8mb3_general_ci",
"7",
"8",
"9: utf8mb3_general_ci",
"10: utf8mb3_general_ci",
"11: utf8mb3_general_ci"
],
"Inputs": [
{
"OperatorType": "Distinct",
"Collations": [
"0: utf8mb3_general_ci",
"1: utf8mb3_general_ci",
"2: utf8mb3_general_ci",
"3: utf8mb3_general_ci",
"4: utf8mb3_general_ci",
"5: utf8mb3_general_ci",
"6: utf8mb3_general_ci",
"7",
"8",
"9: utf8mb3_general_ci",
"10: utf8mb3_general_ci",
"11: utf8mb3_general_ci"
],
"OperatorType": "Concatenate",
"Inputs": [
{
"OperatorType": "Concatenate",
"Inputs": [
{
"OperatorType": "Route",
"Variant": "DBA",
"Keyspace": {
"Name": "main",
"Sharded": false
},
"FieldQuery": "select `CONSTRAINT_CATALOG`, `CONSTRAINT_SCHEMA`, `CONSTRAINT_NAME`, TABLE_CATALOG, TABLE_SCHEMA, `TABLE_NAME`, `COLUMN_NAME`, ORDINAL_POSITION, POSITION_IN_UNIQUE_CONSTRAINT, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME from information_schema.key_column_usage as kcu where 1 != 1",
"Query": "select distinct `CONSTRAINT_CATALOG`, `CONSTRAINT_SCHEMA`, `CONSTRAINT_NAME`, TABLE_CATALOG, TABLE_SCHEMA, `TABLE_NAME`, `COLUMN_NAME`, ORDINAL_POSITION, POSITION_IN_UNIQUE_CONSTRAINT, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME from information_schema.key_column_usage as kcu where kcu.table_schema = :__vtschemaname /* VARCHAR */ and kcu.`table_name` = :kcu_table_name /* VARCHAR */",
"SysTableTableName": "[kcu_table_name:'user_extra']",
"SysTableTableSchema": "['user']",
"Table": "information_schema.key_column_usage"
},
{
"OperatorType": "Route",
"Variant": "DBA",
"Keyspace": {
"Name": "main",
"Sharded": false
},
"FieldQuery": "select `CONSTRAINT_CATALOG`, `CONSTRAINT_SCHEMA`, `CONSTRAINT_NAME`, TABLE_CATALOG, TABLE_SCHEMA, `TABLE_NAME`, `COLUMN_NAME`, ORDINAL_POSITION, POSITION_IN_UNIQUE_CONSTRAINT, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME from information_schema.key_column_usage as kcu where 1 != 1",
"Query": "select distinct `CONSTRAINT_CATALOG`, `CONSTRAINT_SCHEMA`, `CONSTRAINT_NAME`, TABLE_CATALOG, TABLE_SCHEMA, `TABLE_NAME`, `COLUMN_NAME`, ORDINAL_POSITION, POSITION_IN_UNIQUE_CONSTRAINT, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME from information_schema.key_column_usage as kcu where kcu.table_schema = :__vtschemaname /* VARCHAR */ and kcu.`table_name` = :kcu_table_name1 /* VARCHAR */",
"SysTableTableName": "[kcu_table_name1:'music']",
"SysTableTableSchema": "['user']",
"Table": "information_schema.key_column_usage"
}
]
"OperatorType": "Route",
"Variant": "DBA",
"Keyspace": {
"Name": "main",
"Sharded": false
},
"FieldQuery": "select `CONSTRAINT_CATALOG`, `CONSTRAINT_SCHEMA`, `CONSTRAINT_NAME`, TABLE_CATALOG, TABLE_SCHEMA, `TABLE_NAME`, `COLUMN_NAME`, ORDINAL_POSITION, POSITION_IN_UNIQUE_CONSTRAINT, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME from information_schema.key_column_usage as kcu where 1 != 1",
"Query": "select distinct `CONSTRAINT_CATALOG`, `CONSTRAINT_SCHEMA`, `CONSTRAINT_NAME`, TABLE_CATALOG, TABLE_SCHEMA, `TABLE_NAME`, `COLUMN_NAME`, ORDINAL_POSITION, POSITION_IN_UNIQUE_CONSTRAINT, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME from information_schema.key_column_usage as kcu where kcu.table_schema = :__vtschemaname /* VARCHAR */ and kcu.`table_name` = :kcu_table_name /* VARCHAR */ and `CONSTRAINT_NAME` = 'primary'",
"SysTableTableName": "[kcu_table_name:'user_extra']",
"SysTableTableSchema": "['user']",
"Table": "information_schema.key_column_usage"
},
{
"OperatorType": "Route",
"Variant": "DBA",
"Keyspace": {
"Name": "main",
"Sharded": false
},
"FieldQuery": "select `CONSTRAINT_CATALOG`, `CONSTRAINT_SCHEMA`, `CONSTRAINT_NAME`, TABLE_CATALOG, TABLE_SCHEMA, `TABLE_NAME`, `COLUMN_NAME`, ORDINAL_POSITION, POSITION_IN_UNIQUE_CONSTRAINT, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME from information_schema.key_column_usage as kcu where 1 != 1",
"Query": "select distinct `CONSTRAINT_CATALOG`, `CONSTRAINT_SCHEMA`, `CONSTRAINT_NAME`, TABLE_CATALOG, TABLE_SCHEMA, `TABLE_NAME`, `COLUMN_NAME`, ORDINAL_POSITION, POSITION_IN_UNIQUE_CONSTRAINT, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME from information_schema.key_column_usage as kcu where kcu.table_schema = :__vtschemaname /* VARCHAR */ and kcu.`table_name` = :kcu_table_name1 /* VARCHAR */ and `CONSTRAINT_NAME` = 'primary'",
"SysTableTableName": "[kcu_table_name1:'music']",
"SysTableTableSchema": "['user']",
"Table": "information_schema.key_column_usage"
}
]
}
Expand Down
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