Example #1
0
// GetInfoSchema gets TxnCtx InfoSchema if snapshot schema is not set,
// Otherwise, snapshot schema is returned.
func GetInfoSchema(ctx context.Context) infoschema.InfoSchema {
	sessVar := ctx.GetSessionVars()
	var is infoschema.InfoSchema
	if snap := sessVar.SnapshotInfoschema; snap != nil {
		is = snap.(infoschema.InfoSchema)
		log.Infof("[%d] use snapshot schema %d", sessVar.ConnectionID, is.SchemaMetaVersion())
	} else {
		is = sessVar.TxnCtx.InfoSchema.(infoschema.InfoSchema)
	}
	return is
}
Example #2
0
// Compile compiles an ast.StmtNode to an ast.Statement.
// After preprocessed and validated, it will be optimized to a plan,
// then wrappped to an adapter *statement as stmt.Statement.
func (c *Compiler) Compile(ctx context.Context, node ast.StmtNode) (ast.Statement, error) {
	stmtNodeCounter.WithLabelValues(statementLabel(node)).Inc()
	if _, ok := node.(*ast.UpdateStmt); ok {
		sVars := variable.GetSessionVars(ctx)
		sVars.InUpdateStmt = true
		defer func() {
			sVars.InUpdateStmt = false
		}()
	}

	var is infoschema.InfoSchema
	if snap := variable.GetSessionVars(ctx).SnapshotInfoschema; snap != nil {
		is = snap.(infoschema.InfoSchema)
		log.Infof("use snapshot schema %d", is.SchemaMetaVersion())
	} else {
		is = sessionctx.GetDomain(ctx).InfoSchema()
		binloginfo.SetSchemaVersion(ctx, is.SchemaMetaVersion())
	}
	if err := plan.Preprocess(node, is, ctx); err != nil {
		return nil, errors.Trace(err)
	}
	// Validate should be after NameResolve.
	if err := plan.Validate(node, false); err != nil {
		return nil, errors.Trace(err)
	}
	p, err := plan.Optimize(ctx, node, is)
	if err != nil {
		return nil, errors.Trace(err)
	}
	_, isDDL := node.(ast.DDLNode)
	sa := &statement{
		is:    is,
		plan:  p,
		text:  node.Text(),
		isDDL: isDDL,
	}
	return sa, nil
}