Skip to content

Fix column offset tracking for UNIONs to be case insensitive. #19139

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
arthurschreiber merged 1 commit into from
Jan 16, 2026
Merged

Fix column offset tracking for UNIONs to be case insensitive. #19139

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
34 changes: 16 additions & 18 deletions go/vt/vtgate/planbuilder/operators/union.go
View file
Open in desktop
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))))
Copy link
Member

@mattlord mattlord Jan 15, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm not saying this is wrong, I don't know so asking. Is panic (crashing the vtgate) the right thing to do vs returning a query error?

Copy link
Member Author

@arthurschreiber arthurschreiber Jan 15, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is a bit confusing, but panic inside the planner package does not crash the vtgate, it's the canonical way to return an error from inside the planner back to the vtgate.

}

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
143 changes: 65 additions & 78 deletions go/vt/vtgate/planbuilder/testdata/union_cases.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1306,43 +1306,37 @@
"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']"
},
{
"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']"
}
]
"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']"
},
{
"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']"
}
]
}
Expand Down Expand Up @@ -1385,54 +1379,48 @@
"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']"
},
{
"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']"
}
]
"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']"
},
{
"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']"
}
]
}
Expand Down Expand Up @@ -2138,5 +2126,4 @@
]
}
}

]
Loading