MongoDB MongoDB.Driver.GridFS.Delete 上的 createIndexes 异常

Question

我正在使用 C# MongoDB.Driver，版本=1.10.1.73。

请注意，我知道 this question，不是我的问题。

错误信息：

MongoDB.Driver.MongoWriteConcernException: Command 'createIndexes' failed: exception: Index with name: filename_1_uploadDate_1 already exists with different options (response: { "createdCollectionAutomatically" : false, "numIndexesBefore" : 4, "errmsg" : "exception: Index with name: filename_1_uploadDate_1 already exists with different options", "code" : 85, "ok" : 0.0 })

MongoDatabase _database;
var query = MongoDB.Driver.Builders.Query.And(
    MongoDB.Driver.Builders.Query.EQ(ColumnFilename, filePath),
    MongoDB.Driver.Builders.Query.EQ(ColumnWidth, width),
    MongoDB.Driver.Builders.Query.EQ(ColumnHeight, height));

var mongoFileInfo = _database.GridFS.FindOne(query);
if (mongoFileInfo != null) { 
    var mongoStream = mongoFileInfo.OpenRead();
    if (/*some condition*/) {
        mongoStream.Close();
        mongoStream.Dispose();
        mongoFileInfo.Delete(); // exception here
    }

完整堆栈跟踪：

MongoDB.Driver.MongoCollection.CreateIndex(IMongoIndexKeys keys, IMongoIndexOptions options)
MongoDB.Driver.MongoCollection.CreateIndex(IMongoIndexKeys keys)
MongoDB.Driver.MongoCollection.CreateIndex(String[] keyNames)
MongoDB.Driver.GridFS.MongoGridFS.EnsureIndexes(Int32 maxFiles)
MongoDB.Driver.GridFS.MongoGridFS.EnsureIndexes()
MongoDB.Driver.GridFS.MongoGridFSFileInfo.Delete()

Answer 1

filename_1_uploadDate_1 索引是在我的 Mongo 服务器版本 3.0.7 上默认创建的。 unique 的默认设置是 'not unique'。每当某些代码强制该索引是唯一的（我认为它应该是唯一的）时，上述异常发生在从 Mongo 中删除时。

解决方案：如果索引不存在，则创建它，如果存在且唯一，则重新创建为不唯一。

            CommandResult cr = null;
            IndexOptionsDocument NotUnique = new IndexOptionsDocument("unique", false);
            IndexKeysDocument fileNameUploadDateIdx = new IndexKeysDocument(
                new List<BsonElement> { 
                        new BsonElement(ColumnFilename, 1), 
                        new BsonElement(ColumnUploadDate, 1) });
            var index = indexes.FirstOrDefault(
                i => i.Key.Equals(fileNameUploadDateIdx.ToBsonDocument()));

            if (index == null)
            {
                cr = files.CreateIndex(fileNameUploadDateIdx, NotUnique);
                if (!cr.Ok) {
                    //Cannot create uploadDate index
                }
            }
            else if (index.IsUnique)
            {
                cr = files.DropIndexByName(index.Name);
                if (!cr.Ok) {
                    // Cannot drop index filename_1_uploadDate_1. 
                }
                else
                {
                    cr = files.CreateIndex(fileNameUploadDateIdx, NotUnique);
                    if (!cr.Ok) {
                    //Cannot create uploadDate index
                    }
                }
            }

根据 Mongo docs version 3.2 there's no way to modify options on an index without dropping and creating it all over again. This question tackles this too, and this answer 提供了一种扩展方法来包装此丢弃并从头开始重新创建行为。

MongoDB MongoDB.Driver.GridFS.Delete 上的 createIndexes 异常

MongoDB createIndexes exception on MongoDB.Driver.GridFS.Delete

c#

mongodb

mongodb-query

mongodb-.net-driver