mongodb query performance

, you can directly add the index input: {"name": 1, "Age":-1. Do not drop the table after creating an index. 2. OptimizationCodeImproper use of the method will significantly affect mongdb performance. Here I will list my usage experience: A. simply update the data using template. updatefirst () or template. updatemulti () instead of template. findandmodify (); B. Simply add a data operation and use 'template. insert () 'instead of 'template. Sa

waste. Query Cache Fragmentation Rate = Qcache_free_blocks/qcache_total_blocks * 100% If the query cache fragmentation rate exceeds 20%, you can use flush query cache to defragment the cache. Or try reducing query_cache_min_res_unit if your queries are small data volumes. Query Cache utilization = (query_cache_s

First look at the MSYQL logical framework: Images from high-performance MySQL If Querycache is used, when the query receives one and the same query, the server retrieves the results from the query cache instead of parsing and executing the same query again. This can gre

MongoDB learning notes (query) Postedon1. basic query: Construct the query data. Db. test. findOne () {_ id: ObjectId (4fd58ecbb9ac507e96276f1a), name: stephen, age: 35, genda: male, email: stephen@hotmail.com} -- Multi-condition query. The following example is equivalent

I. PrincipleThe principle of Zabbix monitoring MongoDB is through echo "Db.serverstatus ()" | MONGO Admin to see the status of MongoDBTwo Server Configuration1) Add global variables for MONGO# vim/etc/profile.d/mongo.shExport Path=/usr/local/mongodb/bin: $PATH# . /etc/profile.d/mongo.sh2) After execution you can see some status information of MongoDB# echo "Db.se

I. PrincipleThe principle of Zabbix monitoring MongoDB is through echo "Db.serverstatus ()" | MONGO Admin to see the status of MongoDBTwo Server Configuration1) Add global variables for MONGO# vim/etc/profile.d/mongo.shExport Path=/usr/local/mongodb/bin: $PATH# . /etc/profile.d/mongo.sh2) After execution you can see some status information of MongoDB# echo "Db.se

MySQL query cache settings improve MySQL query performance and cache mysql First, let's take a look at the MSYQL logical framework: The image comes from high-performance mysql If QueryCache is used, the server will retrieve the results from the query cache when the

({"name": {"$not": {"$in": ["Stephen2", "Stephen1"]}}){"_id": ObjectId ("4fd58ecbb9ac507e96276f1a"), "name": "Stephen", "Age": +, "Genda": "Male", "email": "[email protected]" } 3. Query for the null data type:--When a query with null data is made, all values are null and documents that do not contain the specified key are retrieved. > Db.test.find ({"x": null}){"_id": ObjectId ("4FD59D30B9AC507E96276F1B"

The MongoDB query document uses the Find () method. The Find () method displays all documents in an unstructured manner. Grammar Db.collection.find (query, projection) query: Optional, use the query operator to specify the query

The company database grows with time, the data is more and more, the query speed is also more and more slow. Into the database to see a bit, hundreds of thousands of of the data, the query is really time-consuming.To improve the query performance of SQL, we generally consider the index as the first consideration. In fa

Label:Do you encounter performance problems when using MongoDB? Here is a summary of the five steps of MongoDB performance optimization, which I hope will help. First step: Find the slow statement In general, query statements are too slow and

The following articles mainly show you how to improve SQL query performance in SAP applications due to DB2 performance optimization, if you are interested in improving SQL query performance in the SAP application of DB2 performance