1// Copyright 2018 Google LLC 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15package spanner 16 17import ( 18 "context" 19 20 "cloud.google.com/go/internal/trace" 21 "github.com/googleapis/gax-go/v2" 22 sppb "google.golang.org/genproto/googleapis/spanner/v1" 23 "google.golang.org/grpc/codes" 24) 25 26// PartitionedUpdate executes a DML statement in parallel across the database, 27// using separate, internal transactions that commit independently. The DML 28// statement must be fully partitionable: it must be expressible as the union 29// of many statements each of which accesses only a single row of the table. The 30// statement should also be idempotent, because it may be applied more than once. 31// 32// PartitionedUpdate returns an estimated count of the number of rows affected. 33// The actual number of affected rows may be greater than the estimate. 34func (c *Client) PartitionedUpdate(ctx context.Context, statement Statement) (count int64, err error) { 35 ctx = trace.StartSpan(ctx, "cloud.google.com/go/spanner.PartitionedUpdate") 36 defer func() { trace.EndSpan(ctx, err) }() 37 if err := checkNestedTxn(ctx); err != nil { 38 return 0, err 39 } 40 var ( 41 s *session 42 sh *sessionHandle 43 ) 44 // Create session. 45 s, err = c.sc.createSession(ctx) 46 if err != nil { 47 return 0, toSpannerError(err) 48 } 49 // Delete the session at the end of the request. If the PDML statement 50 // timed out or was cancelled, the DeleteSession request might not succeed, 51 // but the session will eventually be garbage collected by the server. 52 defer s.delete(ctx) 53 sh = &sessionHandle{session: s} 54 // Create the parameters and the SQL request, but without a transaction. 55 // The transaction reference will be added by the executePdml method. 56 params, paramTypes, err := statement.convertParams() 57 if err != nil { 58 return 0, toSpannerError(err) 59 } 60 req := &sppb.ExecuteSqlRequest{ 61 Session: sh.getID(), 62 Sql: statement.SQL, 63 Params: params, 64 ParamTypes: paramTypes, 65 } 66 67 // Make a retryer for Aborted errors. 68 // TODO: use generic Aborted retryer when merged with master 69 retryer := gax.OnCodes([]codes.Code{codes.Aborted}, DefaultRetryBackoff) 70 // Execute the PDML and retry if the transaction is aborted. 71 executePdmlWithRetry := func(ctx context.Context) (int64, error) { 72 for { 73 count, err := executePdml(ctx, sh, req) 74 if err == nil { 75 return count, nil 76 } 77 delay, shouldRetry := retryer.Retry(err) 78 if !shouldRetry { 79 return 0, err 80 } 81 if err := gax.Sleep(ctx, delay); err != nil { 82 return 0, err 83 } 84 } 85 } 86 return executePdmlWithRetry(ctx) 87} 88 89// executePdml executes the following steps: 90// 1. Begin a PDML transaction 91// 2. Add the ID of the PDML transaction to the SQL request. 92// 3. Execute the update statement on the PDML transaction 93// 94// Note that PDML transactions cannot be committed or rolled back. 95func executePdml(ctx context.Context, sh *sessionHandle, req *sppb.ExecuteSqlRequest) (count int64, err error) { 96 // Begin transaction. 97 res, err := sh.getClient().BeginTransaction(contextWithOutgoingMetadata(ctx, sh.getMetadata()), &sppb.BeginTransactionRequest{ 98 Session: sh.getID(), 99 Options: &sppb.TransactionOptions{ 100 Mode: &sppb.TransactionOptions_PartitionedDml_{PartitionedDml: &sppb.TransactionOptions_PartitionedDml{}}, 101 }, 102 }) 103 if err != nil { 104 return 0, toSpannerError(err) 105 } 106 // Add a reference to the PDML transaction on the ExecuteSql request. 107 req.Transaction = &sppb.TransactionSelector{ 108 Selector: &sppb.TransactionSelector_Id{Id: res.Id}, 109 } 110 resultSet, err := sh.getClient().ExecuteSql(ctx, req) 111 if err != nil { 112 return 0, err 113 } 114 if resultSet.Stats == nil { 115 return 0, spannerErrorf(codes.InvalidArgument, "query passed to Update: %q", req.Sql) 116 } 117 return extractRowCount(resultSet.Stats) 118} 119