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sql: run check constraint mutations and validation by schema changer #32504

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merged 1 commit into from
Jan 10, 2019
+1,333 −659
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sql: run check constraint mutations and validation by schema changer #32504

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53 changes: 33 additions & 20 deletions pkg/sql/alter_table.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,6 @@
package sql

import (
"bytes"
"context"
gojson "encoding/json"
"fmt"
Expand Down Expand Up @@ -180,6 +179,11 @@ func (n *alterTableNode) startExec(params runParams) error {
for k := range info {
inuseNames[k] = struct{}{}
}
for _, m := range n.tableDesc.Mutations {
if ck := m.GetCheck(); ck != nil {
inuseNames[ck.Name] = struct{}{}
}
}
switch d := t.ConstraintDef.(type) {
case *tree.UniqueConstraintTableDef:
if d.PrimaryKey {
Expand Down Expand Up @@ -213,14 +217,17 @@ func (n *alterTableNode) startExec(params runParams) error {
}

case *tree.CheckConstraintTableDef:
// A previous command could have added a column which the new constraint uses,
// allocate IDs now.
if err != n.tableDesc.AllocateIDs() {
return err
}
ck, err := MakeCheckConstraint(params.ctx,
n.tableDesc, d, inuseNames, &params.p.semaCtx, params.EvalContext(), n.n.Table)
if err != nil {
return err
}
ck.Validity = sqlbase.ConstraintValidity_Unvalidated
n.tableDesc.Checks = append(n.tableDesc.Checks, ck)
descriptorChanged = true
n.tableDesc.AddCheckMutation(*ck, sqlbase.DescriptorMutation_ADD)

case *tree.ForeignKeyConstraintTableDef:
for _, colName := range d.FromCols {
Expand Down Expand Up @@ -404,6 +411,8 @@ func (n *alterTableNode) startExec(params runParams) error {
return err
} else if !used {
validChecks = append(validChecks, check)
} else {
n.tableDesc.MaybeAddCheckDropMutation(*check)
}
}

Expand All @@ -419,6 +428,17 @@ func (n *alterTableNode) startExec(params runParams) error {
return err
}

// Check that no dependent check constraints are queued to be added.
for _, m := range n.tableDesc.Mutations {
if ck := m.GetCheck(); ck != nil && m.Direction == sqlbase.DescriptorMutation_ADD {
if used, err := ck.UsesColumn(n.tableDesc.TableDesc(), col.ID); err != nil {
return err
} else if used {
return fmt.Errorf("referencing constraint %q in the middle of being added, try again later", ck.Name)
}
}
}

found := false
for i := range n.tableDesc.Columns {
if n.tableDesc.Columns[i].ID == col.ID {
Expand Down Expand Up @@ -451,13 +471,19 @@ func (n *alterTableNode) startExec(params runParams) error {
case sqlbase.ConstraintTypeUnique:
return fmt.Errorf("UNIQUE constraint depends on index %q, use DROP INDEX with CASCADE if you really want to drop it", t.Constraint)
case sqlbase.ConstraintTypeCheck:
for i := range n.tableDesc.Checks {
if n.tableDesc.Checks[i].Name == name {
found := false
for i, ck := range n.tableDesc.Checks {
if ck.Name == name {
n.tableDesc.MaybeAddCheckDropMutation(*ck)
n.tableDesc.Checks = append(n.tableDesc.Checks[:i], n.tableDesc.Checks[i+1:]...)
descriptorChanged = true
found = true
break
}
}
if !found {
return fmt.Errorf("constraint %q in the middle of being added, try again later", t.Constraint)
}
case sqlbase.ConstraintTypeFK:
idx, err := n.tableDesc.FindIndexByID(details.Index.ID)
if err != nil {
Expand Down Expand Up @@ -496,7 +522,7 @@ func (n *alterTableNode) startExec(params runParams) error {
}
}
if !found {
panic("constraint returned by GetConstraintInfo not found")
return fmt.Errorf("constraint %q in the middle of being added, try again later", t.Constraint)
}
ck := n.tableDesc.Checks[idx]
if err := params.p.validateCheckExpr(
Expand Down Expand Up @@ -772,19 +798,6 @@ func applyColumnMutation(
return nil
}

func labeledRowValues(cols []sqlbase.ColumnDescriptor, values tree.Datums) string {
var s bytes.Buffer
for i := range cols {
if i != 0 {
s.WriteString(`, `)
}
s.WriteString(cols[i].Name)
s.WriteString(`=`)
s.WriteString(values[i].String())
}
return s.String()
}

// injectTableStats implements the INJECT STATISTICS command, which deletes any
// existing statistics on the table and replaces them with the statistics in the
// given json object (in the same format as the result of SHOW STATISTICS USING
Expand Down
78 changes: 73 additions & 5 deletions pkg/sql/backfill.go
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Original file line number Diff line number Diff line change
Expand Up @@ -41,9 +41,15 @@ const (
// processed per chunk during column truncate or backfill.
columnTruncateAndBackfillChunkSize = 200

// checkConstraintBackfillChunkSize is the maximum number of rows
// processed per chunk during check constraint validation. This value
// is larger than the other chunk constants because the operation involves
// only running a scan and does not write.
checkConstraintBackfillChunkSize = 1600

// indexTruncateChunkSize is the maximum number of index entries truncated
// per chunk during an index truncation. This value is larger than the
// other chunk constants because the operation involves only running a
// per chunk during an index truncation. This value is larger than other
// chunk constants because the operation involves only running a
// DeleteRange().
indexTruncateChunkSize = 600

Expand Down Expand Up @@ -132,13 +138,18 @@ func (sc *SchemaChanger) runBackfill(
tableDesc.Name, tableDesc.Version, sc.mutationID)

needColumnBackfill := false
needCheckValidation := false
for _, m := range tableDesc.Mutations {
if m.MutationID != sc.mutationID {
break
}
switch m.Direction {
case sqlbase.DescriptorMutation_ADD:
switch t := m.Descriptor_.(type) {
case *sqlbase.DescriptorMutation_Check:
if t.Check.Validity == sqlbase.ConstraintValidity_Validating {
needCheckValidation = true
}
case *sqlbase.DescriptorMutation_Column:
if sqlbase.ColumnNeedsBackfill(m.GetColumn()) {
needColumnBackfill = true
Expand All @@ -151,6 +162,8 @@ func (sc *SchemaChanger) runBackfill(

case sqlbase.DescriptorMutation_DROP:
switch t := m.Descriptor_.(type) {
case *sqlbase.DescriptorMutation_Check:
// Nothing to do.
case *sqlbase.DescriptorMutation_Column:
needColumnBackfill = true
case *sqlbase.DescriptorMutation_Index:
Expand Down Expand Up @@ -186,6 +199,13 @@ func (sc *SchemaChanger) runBackfill(
}
}

// Validate checks.
if needCheckValidation {
if err := sc.validateChecks(ctx, evalCtx, lease, version); err != nil {
return err
}
}

return nil
}

Expand All @@ -202,6 +222,18 @@ func (sc *SchemaChanger) getTableVersion(
return tableDesc, nil
}

func (sc *SchemaChanger) validateChecks(
ctx context.Context,
evalCtx *extendedEvalContext,
lease *sqlbase.TableDescriptor_SchemaChangeLease,
version sqlbase.DescriptorVersion,
) error {
return sc.distBackfill(
ctx, evalCtx,
lease, version, checkConstraintBackfill, checkConstraintBackfillChunkSize,
backfill.CheckMutationFilter)
}

func (sc *SchemaChanger) truncateIndexes(
ctx context.Context,
lease *sqlbase.TableDescriptor_SchemaChangeLease,
Expand Down Expand Up @@ -286,6 +318,7 @@ const (
_ backfillType = iota
columnBackfill
indexBackfill
checkConstraintBackfill
)

// getJobIDForMutationWithDescriptor returns a job id associated with a mutation given
Expand Down Expand Up @@ -517,9 +550,9 @@ func runSchemaChangesInTxn(
return nil
}

// Only needed because columnBackfillInTxn() backfills
// all column mutations.
doneColumnBackfill := false
// Only needed because columnBackfillInTxn() and checkValidateInTxn()
// backfills are applied to all related mutations.
doneColumnBackfill, doneCheckValidation := false, false
for _, m := range tableDesc.Mutations {
immutDesc := sqlbase.NewImmutableTableDescriptor(*tableDesc.TableDesc())
switch m.Direction {
Expand All @@ -539,6 +572,15 @@ func runSchemaChangesInTxn(
return err
}

case *sqlbase.DescriptorMutation_Check:
if doneCheckValidation || m.GetCheck().Validity != sqlbase.ConstraintValidity_Validating {
break
}
if err := checkValidateInTxn(ctx, txn, evalCtx, immutDesc, traceKV); err != nil {
return err
}
doneCheckValidation = true

default:
return errors.Errorf("unsupported mutation: %+v", m)
}
Expand All @@ -560,6 +602,9 @@ func runSchemaChangesInTxn(
return err
}

case *sqlbase.DescriptorMutation_Check:
// No-op.

default:
return errors.Errorf("unsupported mutation: %+v", m)
}
Expand All @@ -574,6 +619,29 @@ func runSchemaChangesInTxn(
return nil
}

func checkValidateInTxn(
ctx context.Context,
txn *client.Txn,
evalCtx *tree.EvalContext,
tableDesc *sqlbase.ImmutableTableDescriptor,
traceKV bool,
) error {
var backfiller backfill.CheckBackfiller
if err := backfiller.Init(evalCtx, tableDesc); err != nil {
return err
}

sp := tableDesc.PrimaryIndexSpan()
for sp.Key != nil {
var err error
sp.Key, err = backfiller.RunCheckBackfillChunk(ctx, txn, tableDesc, sp, checkConstraintBackfillChunkSize, traceKV)
if err != nil {
return err
}
}
return nil
}

// columnBackfillInTxn backfills columns for all mutation columns in
// the mutation list.
func columnBackfillInTxn(
Expand Down
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