MongoDB

1. Check the status of the replica setUse Db.runcommand ({"Replsetgetstatus": 1}), or rs.status ();2. Check replication delay Timesource:m1.example.net:30001 syncedto:tue Oct 11:33:40 GMT-0400 (EDT) = 7475 secs ago (2.08hrs) source : m2.example.net:3

The cluster architecture diagram is as follows:Cluster approximate file structure: (192.168.137.101 nodes) Build 3 Replica Sets firstRs1/mongod.confrs1/start.shRs2/mongod.confThe back resembles ...MONGO 192.168.137.101:10001/adminconf = {_id:

The following program uses SOLR as the search module, and the first step in searching for the key is to create an index. The generation of indexes we generally use the data in the database as the data source. But the data in the database is

Aggregating operations on collections that exceed millions records.DBObject match= (dbobject) Json.parse ("{$match: {logtype:{' $in ': [5,9]}}}");D bobject group= (dbobject) Json.parse ("{$ group:{' _id ': ' $domainUrl ', ' count ': {' $sum ': 1}}} '

Operation Record and summary: Show DBS Use some_db (a DB is selected as well as a new db "Note to write data, new some_db cannot be empty") Show collections $inc > db.simple.find () {  "_id"  : objectid ("54E9DC1FA4C00BA20F4432AD"),  "name" :  

Description: Increase the user to operate against the database1. Go to database use dbname2. Adding user rights for the current database is for the current data1. Add and verify the user>Use admin> Db.adduser ("Zjx", "Tsjianxin")> Db.auth ("Zjx",

Mongo DB is a non-relational database (NOSQL) that is currently very popular in the IT industry, and its flexible data storage methods are favored by current it practitioners. Mongo db is a good way to implement object-oriented thinking, in Mongo db,

1.mongo Lock Overview:Features of each version lock:当前版本 生产版本最高是 2.6.7[Production Release (2.6.7)] 开发版本是 3.0.0-rc7[Development Releases (unstable)3.0.0] Version Version >= 2.2 : 支持库级锁，一个db一把锁。目前3.0.0 支持 collection 级别的锁。Ps:mysql's InnoDB and Oracle

MongoDB Start Command mongod parameter descriptionThe main parameters of Mongod are:Basic Configuration --quiet # quiet Output --port Arg # Specify the service port number, default ports 27017

background MapReduce is a very flexible and powerful data aggregation tool. The advantage of this is that a single aggregation task can be decomposed into several small tasks that are assigned to parallel processing on multiple servers. MongoDB also

Objectid is the default type for "_id". It is designed to be light-weight, and different machines can easily generate it with a globally unique homogeneous method.This is the main reason that MongoDB uses objectid instead of other more conventional

Backup[Email protected] bin]#/mongodump-127.0.0.1 database:my_mongodb to dump/My_ MongoDB my_mongodb.system.indexes to dump/my_mongodb/system.indexes.bson 1 objects my_mongodb.user to dump/my_mongodb/user.bson

1: Download MongoDB 2.6 versionHttps://fastdl.mongodb.org/win32/mongodb-win32-x86_64-2008plus-2.6.9.zip2: UnzipTAR-ZXVF Mongodb-linux-x86_64-2.6.9.zipMV mongodb-linux-x86_64-2.6.9 MongoDB　　3: Create data directory and log directory and conf

(This article is also published in my public number "dotnet daily Essence article") The articles recommended today compare Azure Documentdb and MongoDB, as well as some suggestions for use. I think a lot of friends should know about Azure, but there

MongoDB array modifier update data     Here we'll look at the array modifier. Arrays are very useful data structures that we often see and use: not only can they be referenced by a lasso, but they can also be used as a collection. An array modifier,

When making a MongoDB shard, when the MONGOs routing service is enabled, we specify a location for the log to be stored:MONGOs--configdb 127.0.0.1:27019--logpath/var/log/mongodb/mongos.log--pidfilepath/var/run/mongodb/mongos.pid--

The specific main of master-slave replication is to modify the mongodb.conf configuration file for two hostsMongoDB supports one master multiple from replication (different instances in the/data directory to create different directories)Master

JDBC-database update Operation Programming (3) First, create a static method. The Code is as follows: public static Statement getStatement(){ Statement st = null; try { Class.forName("com.mysql.jdbc.Driver");

03. JDBC database programming-processing DML statements Void AddBatch(String SQL) Adds the given SQL command to the current list of commands for this Statement object. Void

JPA (3): JPA + Hibernate basic learning In the first article of this series, we have mentioned JPA and Hibernate. Is the role of the two in the system architecture: We can draw two conclusions from a piece of film: first, the main role of JPA is