[release-18.0] Avoid rewriting unsharded queries and split semantic analysis in two (#15217) (#15229)

Signed-off-by: Andres Taylor <andres@planetscale.com>
Signed-off-by: Florent Poinsard <35779988+frouioui@users.noreply.github.com>
Co-authored-by: Florent Poinsard <35779988+frouioui@users.noreply.github.com>

Author: vitess-bot[bot]

go/vt/vtgate/planbuilder/testdata/ddl_cases.json

@@ -260,7 +260,7 @@
           "Name": "main",
           "Sharded": false
         },
-        "Query": "create view view_a as select col1, col2 from (select col1, col2 from unsharded where id = 1 union select col1, col2 from unsharded where id = 3) as a"
+        "Query": "create view view_a as select * from (select col1, col2 from unsharded where id = 1 union select col1, col2 from unsharded where id = 3) as a"
       },
       "TablesUsed": [
         "main.view_a"

go/vt/vtgate/planbuilder/testdata/filter_cases.json

@@ -4062,7 +4062,7 @@
           "Sharded": false
         },
         "FieldQuery": "select col + 2 as a from unsharded where 1 != 1",
-        "Query": "select col + 2 as a from unsharded having col + 2 = 42",
+        "Query": "select col + 2 as a from unsharded having a = 42",
         "Table": "unsharded"
       },
       "TablesUsed": [

go/vt/vtgate/planbuilder/testdata/foreignkey_cases.json

@@ -1132,7 +1132,7 @@
                   "Sharded": false
                 },
                 "FieldQuery": "select 1 from u_tbl8 left join u_tbl9 on u_tbl9.col9 = 'foo' where 1 != 1",
-                "Query": "select 1 from u_tbl8 left join u_tbl9 on u_tbl9.col9 = 'foo' where (u_tbl8.col8) in ::fkc_vals and u_tbl9.col9 is null limit 1 lock in share mode",
+                "Query": "select 1 from u_tbl8 left join u_tbl9 on u_tbl9.col9 = 'foo' where u_tbl9.col9 is null and (u_tbl8.col8) in ::fkc_vals limit 1 lock in share mode",
                 "Table": "u_tbl8, u_tbl9"
               },
               {
@@ -1208,7 +1208,7 @@
                   "Sharded": false
                 },
                 "FieldQuery": "select 1 from u_tbl4 left join u_tbl3 on u_tbl3.col3 = 'foo' where 1 != 1",
-                "Query": "select 1 from u_tbl4 left join u_tbl3 on u_tbl3.col3 = 'foo' where (u_tbl4.col4) in ::fkc_vals and u_tbl3.col3 is null limit 1 lock in share mode",
+                "Query": "select 1 from u_tbl4 left join u_tbl3 on u_tbl3.col3 = 'foo' where u_tbl3.col3 is null and (u_tbl4.col4) in ::fkc_vals limit 1 lock in share mode",
                 "Table": "u_tbl3, u_tbl4"
               },
               {
@@ -1220,7 +1220,7 @@
                   "Sharded": false
                 },
                 "FieldQuery": "select 1 from u_tbl4, u_tbl9 where 1 != 1",
-                "Query": "select 1 from u_tbl4, u_tbl9 where (u_tbl4.col4) in ::fkc_vals and (u_tbl9.col9) not in (('foo')) and u_tbl4.col4 = u_tbl9.col9 limit 1 lock in share mode",
+                "Query": "select 1 from u_tbl4, u_tbl9 where u_tbl4.col4 = u_tbl9.col9 and (u_tbl4.col4) in ::fkc_vals and ('foo' is null or (u_tbl9.col9) not in (('foo'))) and u_tbl4.col4 = u_tbl9.col9 and (u_tbl4.col4) in ::fkc_vals and ('foo' is null or (u_tbl9.col9) not in (('foo'))) limit 1 lock in share mode",
                 "Table": "u_tbl4, u_tbl9"
               },
               {
@@ -1297,7 +1297,7 @@
                   "Sharded": false
                 },
                 "FieldQuery": "select 1 from u_tbl4 left join u_tbl3 on u_tbl3.col3 = :v1 where 1 != 1",
-                "Query": "select 1 from u_tbl4 left join u_tbl3 on u_tbl3.col3 = :v1 where (u_tbl4.col4) in ::fkc_vals and u_tbl3.col3 is null limit 1 lock in share mode",
+                "Query": "select 1 from u_tbl4 left join u_tbl3 on u_tbl3.col3 = :v1 where u_tbl3.col3 is null and (u_tbl4.col4) in ::fkc_vals limit 1 lock in share mode",
                 "Table": "u_tbl3, u_tbl4"
               },
               {
@@ -1309,7 +1309,7 @@
                   "Sharded": false
                 },
                 "FieldQuery": "select 1 from u_tbl4, u_tbl9 where 1 != 1",
-                "Query": "select 1 from u_tbl4, u_tbl9 where (u_tbl4.col4) in ::fkc_vals and (:v1 is null or (u_tbl9.col9) not in ((:v1))) and u_tbl4.col4 = u_tbl9.col9 limit 1 lock in share mode",
+                "Query": "select 1 from u_tbl4, u_tbl9 where u_tbl4.col4 = u_tbl9.col9 and (u_tbl4.col4) in ::fkc_vals and (:v1 is null or (u_tbl9.col9) not in ((:v1))) and u_tbl4.col4 = u_tbl9.col9 and (u_tbl4.col4) in ::fkc_vals and (:v1 is null or (u_tbl9.col9) not in ((:v1))) limit 1 lock in share mode",
                 "Table": "u_tbl4, u_tbl9"
               },
               {

go/vt/vtgate/planbuilder/testdata/from_cases.json

@@ -711,8 +711,8 @@
           "Name": "main",
           "Sharded": false
         },
-        "FieldQuery": "select m1.col from unsharded as m1 join unsharded as m2 where 1 != 1",
-        "Query": "select m1.col from unsharded as m1 join unsharded as m2",
+        "FieldQuery": "select m1.col from unsharded as m1 straight_join unsharded as m2 where 1 != 1",
+        "Query": "select m1.col from unsharded as m1 straight_join unsharded as m2",
         "Table": "unsharded"
       },
       "TablesUsed": [
@@ -3989,8 +3989,8 @@
           "Name": "main",
           "Sharded": false
         },
-        "FieldQuery": "select A.col1 as col1, A.col2 as col2, B.col2 as col2 from unsharded_authoritative as A left join unsharded_authoritative as B on A.col1 = B.col1 where 1 != 1",
-        "Query": "select A.col1 as col1, A.col2 as col2, B.col2 as col2 from unsharded_authoritative as A left join unsharded_authoritative as B on A.col1 = B.col1",
+        "FieldQuery": "select * from unsharded_authoritative as A left join unsharded_authoritative as B using (col1) where 1 != 1",
+        "Query": "select * from unsharded_authoritative as A left join unsharded_authoritative as B using (col1)",
         "Table": "unsharded_authoritative"
       },
       "TablesUsed": [

go/vt/vtgate/planbuilder/testdata/select_cases.json

@@ -1428,8 +1428,8 @@
           "Name": "main",
           "Sharded": false
         },
-        "FieldQuery": "select col1, col2 from (select col1, col2 from unsharded where 1 != 1 union select col1, col2 from unsharded where 1 != 1) as a where 1 != 1",
-        "Query": "select col1, col2 from (select col1, col2 from unsharded where id = 1 union select col1, col2 from unsharded where id = 3) as a",
+        "FieldQuery": "select * from (select col1, col2 from unsharded where 1 != 1 union select col1, col2 from unsharded where 1 != 1) as a where 1 != 1",
+        "Query": "select * from (select col1, col2 from unsharded where id = 1 union select col1, col2 from unsharded where id = 3) as a",
         "Table": "unsharded"
       },
       "TablesUsed": [
@@ -2544,7 +2544,7 @@
           "Sharded": false
         },
         "FieldQuery": "select 1 from (select col, count(*) as a from unsharded where 1 != 1 group by col) as f left join unsharded as u on f.col = u.id where 1 != 1",
-        "Query": "select 1 from (select col, count(*) as a from unsharded group by col having count(*) > 0 limit 0, 12) as f left join unsharded as u on f.col = u.id",
+        "Query": "select 1 from (select col, count(*) as a from unsharded group by col having a > 0 limit 0, 12) as f left join unsharded as u on f.col = u.id",
         "Table": "unsharded"
       },
       "TablesUsed": [

go/vt/vtgate/planbuilder/testdata/union_cases.json

@@ -882,7 +882,7 @@
           "Sharded": false
         },
         "FieldQuery": "(select 1 from unsharded where 1 != 1 union select 1 from unsharded where 1 != 1 union all select 1 from unsharded where 1 != 1) union select 1 from unsharded where 1 != 1 union all select 1 from unsharded where 1 != 1",
-        "Query": "(select 1 from unsharded union select 1 from unsharded union all select 1 from unsharded order by `1` asc) union select 1 from unsharded union all select 1 from unsharded order by `1` asc",
+        "Query": "(select 1 from unsharded union select 1 from unsharded union all select 1 from unsharded order by 1 asc) union select 1 from unsharded union all select 1 from unsharded order by 1 asc",
         "Table": "unsharded"
       },
       "TablesUsed": [

go/vt/vtgate/semantics/analyzer.go

@@ -25,47 +25,60 @@ import (
 // analyzer controls the flow of the analysis.
 // It starts the tree walking and controls which part of the analysis sees which parts of the tree
 type analyzer struct {
-	scoper   *scoper
-	tables   *tableCollector
-	binder   *binder
-	typer    *typer
-	rewriter *earlyRewriter
-	sig      QuerySignature
+	scoper      *scoper
+	earlyTables *earlyTableCollector
+	tables      *tableCollector
+	binder      *binder
+	typer       *typer
+	rewriter    *earlyRewriter
+	sig         QuerySignature
+	si          SchemaInformation
+	currentDb   string
 
 	err          error
 	inProjection int
 
-	projErr      error
-	unshardedErr error
-	warning      string
+	projErr                 error
+	unshardedErr            error
+	warning                 string
+	singleUnshardedKeyspace bool
+	fullAnalysis            bool
 }
 
 // newAnalyzer create the semantic analyzer
-func newAnalyzer(dbName string, si SchemaInformation) *analyzer {
+func newAnalyzer(dbName string, si SchemaInformation, fullAnalysis bool) *analyzer {
 	// TODO  dependencies between these components are a little tangled. We should try to clean up
 	s := newScoper()
 	a := &analyzer{
-		scoper: s,
-		tables: newTableCollector(s, si, dbName),
-		typer:  newTyper(),
+		scoper:       s,
+		earlyTables:  newEarlyTableCollector(si, dbName),
+		typer:        newTyper(),
+		si:           si,
+		currentDb:    dbName,
+		fullAnalysis: fullAnalysis,
 	}
 	s.org = a
-	a.tables.org = a
+	return a
+}
 
-	b := newBinder(s, a, a.tables, a.typer)
-	a.binder = b
+func (a *analyzer) lateInit() {
+	a.tables = a.earlyTables.newTableCollector(a.scoper, a)
+	a.binder = newBinder(a.scoper, a, a.tables, a.typer)
+	a.scoper.binder = a.binder
 	a.rewriter = &earlyRewriter{
-		scoper:          s,
-		binder:          b,
+		scoper:          a.scoper,
+		binder:          a.binder,
 		expandedColumns: map[sqlparser.TableName][]*sqlparser.ColName{},
 	}
-	s.binder = b
-	return a
 }
 
 // Analyze analyzes the parsed query.
 func Analyze(statement sqlparser.Statement, currentDb string, si SchemaInformation) (*SemTable, error) {
-	analyzer := newAnalyzer(currentDb, newSchemaInfo(si))
+	return analyseAndGetSemTable(statement, currentDb, si, false)
+}
+
+func analyseAndGetSemTable(statement sqlparser.Statement, currentDb string, si SchemaInformation, fullAnalysis bool) (*SemTable, error) {
+	analyzer := newAnalyzer(currentDb, newSchemaInfo(si), fullAnalysis)
 
 	// Analysis for initial scope
 	err := analyzer.analyze(statement)
@@ -79,7 +92,7 @@ func Analyze(statement sqlparser.Statement, currentDb string, si SchemaInformati
 
 // AnalyzeStrict analyzes the parsed query, and fails the analysis for any possible errors
 func AnalyzeStrict(statement sqlparser.Statement, currentDb string, si SchemaInformation) (*SemTable, error) {
-	st, err := Analyze(statement, currentDb, si)
+	st, err := analyseAndGetSemTable(statement, currentDb, si, true)
 	if err != nil {
 		return nil, err
 	}
@@ -103,6 +116,27 @@ func (a *analyzer) newSemTable(
 	if isCommented {
 		comments = commentedStmt.GetParsedComments()
 	}
+
+	if a.singleUnshardedKeyspace {
+		return &SemTable{
+			Tables:            a.earlyTables.Tables,
+			Comments:          comments,
+			Warning:           a.warning,
+			Collation:         coll,
+			ExprTypes:         map[sqlparser.Expr]Type{},
+			NotSingleRouteErr: a.projErr,
+			NotUnshardedErr:   a.unshardedErr,
+			Recursive:         ExprDependencies{},
+			Direct:            ExprDependencies{},
+			ColumnEqualities:  map[columnName][]sqlparser.Expr{},
+			ExpandedColumns:   map[sqlparser.TableName][]*sqlparser.ColName{},
+			columns:           map[*sqlparser.Union]sqlparser.SelectExprs{},
+			comparator:        nil,
+			StatementIDs:      a.scoper.statementIDs,
+			QuerySignature:    QuerySignature{},
+		}, nil
+	}
+
 	columns := map[*sqlparser.Union]sqlparser.SelectExprs{}
 	for union, info := range a.tables.unionInfo {
 		columns[union] = info.exprs
@@ -280,10 +314,43 @@ func (a *analyzer) depsForExpr(expr sqlparser.Expr) (direct, recursive TableSet,
 }
 
 func (a *analyzer) analyze(statement sqlparser.Statement) error {
+	_ = sqlparser.Rewrite(statement, nil, a.earlyUp)
+	if a.err != nil {
+		return a.err
+	}
+
+	if a.canShortCut(statement) {
+		return nil
+	}
+
+	a.lateInit()
+
 	_ = sqlparser.Rewrite(statement, a.analyzeDown, a.analyzeUp)
 	return a.err
 }
 
+// canShortCut checks if we are dealing with a single unsharded keyspace and no tables that have managed foreign keys
+// if so, we can stop the analyzer early
+func (a *analyzer) canShortCut(statement sqlparser.Statement) bool {
+	if a.fullAnalysis {
+		return false
+	}
+	ks, _ := singleUnshardedKeyspace(a.earlyTables.Tables)
+	if ks == nil {
+		return false
+	}
+
+	a.singleUnshardedKeyspace = !sqlparser.IsDMLStatement(statement)
+	return a.singleUnshardedKeyspace
+}
+
+// earlyUp collects tables in the query, so we can check
+// if this a single unsharded query we are dealing with
+func (a *analyzer) earlyUp(cursor *sqlparser.Cursor) bool {
+	a.earlyTables.up(cursor)
+	return true
+}
+
 func (a *analyzer) shouldContinue() bool {
 	return a.err == nil
 }