influxdb query

1. Introduction to ToolsPt-query-digest is a tool for analyzing slow queries for MySQL, which analyzes Binlog, general log, Slowlog, It can also be analyzed using showprocesslist or MySQL protocol data crawled by tcpdump. The analysis results can be exported to a file, the analysis process is the parameters of the query statement, and then the parameterized query

1. Introduction to ToolsPt-query-digest is a tool for analyzing slow queries for MySQL, which analyzes Binlog, general log, Slowlog, It can also be analyzed using showprocesslist or MySQL protocol data crawled by tcpdump. The analysis results can be exported to a file, the analysis process is the parameters of the query statement, and then the parameterized query

Multi-table joint QueryYou can create a multi-Table query through a connection. The data queried from multiple tables can come from multiple tables, but appropriate connection conditions must exist between tables. To query multiple tables, you must identify the public columns that are connected to multiple tables. Generally, a comparison operator is used in the WHERE clause to specify the conditions for con

Before getting started, check the latest v1.2 version. Fixed the conflict between the keyboard carriage return event and the control peripheral Event During Quick query. Fixed the syntax error that may occur when you set a Regular Expression During Quick query. Data Provision MethodDatahandlerIt is no longer required to be consistent with the Column Binding Order.DatatableInColumnnameAutomat

[Email protected] log]# pt-query-digest Slowq.log# 200ms User Time, 10ms system time, 24.39M rss, 205.12M vsz# current Date:thu Dec 17 15:32:04 2015# hostname:hank-yoon.com# Files:slowq.log# Overall:8 Total, 2 unique, 0.00 QPS, 0.00x concurrency ________________# time RANGE:2015-12-17 05:00:09 to 15:30:01# Attribute Total min max avg 95% StdDev Median# ============ ======= ======= ======= ======= ======= ======= =======# Exec time 15s 1s 7s 2s 7s 2s

Series Introduction The analysis series of nhibernate3.0 fully reveals new features, applications and various applications of nhibernate3.0 in terms of configuration, mapping, query, session policy, and application.ProgramBased on nhibernte3.0. If you are not familiar with Nhibernate, you can quickly get started with the Nhibernate series Article navigation series. If you are already using Nhibernate, keep up with the nhibernate3.0 series.

IosCoreData framework is used to add, delete, modify, and query context data, association between tables, 1-to-many, 1-to-1, predicate query, and multi-Table connection. -(Void) viewDidLoad {[super viewDidLoad]; [self _ creatTable]; // insert data // [self _ query]; // query data // KVC is overbearing, even if readonl

When you submit a query, MySQL will analyze it to see if some optimization can be done to make it faster to process the query. This section describes how the query optimizer works. If you want to know the optimization methods used by MySQL, you can refer to the MySQL Reference Manual. Of course, the MySQL Query optimiz

Tags: The amount font problem should be controlled backThis section describes the Oracle subquery: The data used by the instance is the EMP employee table under the Scott user in Oracle, dept the Department table with the following data: One, sub-query 1, Concept: Another query embedded in a query, that is, one query

Tags: http knowledge point error variable coin lock table response Long MYQLLogs in MySQL include: error log, binary log, General query log, slow query log, and so on. Here is the main introduction of the more commonly used two features: General query log and slow query log.1) General

In the database query process, sometimes the data records in a table cannot meet the needs of developers or customers. For example, query the student's Course Selection score. The student course selection information and course score information are in two different data tables. The course information table (T_curriculum) contains the course number, course name, course credits, class hours, instructors, and

Tags: style blog HTTP Io OS ar use for SP Review The previous article introduced the mode and based on ADO. although the ORM framework is becoming more and more popular, many small and medium enterprises still use ADO.. Net to perform database operations. With the increasing demand of projects and changing business, ADO. net implementation method will make the original simple single-Table operations more complex, especially when the database table changes, as in the ORM framework, by modifyi

0. Introduction to Grammar:1. Common part code same as seven//Indexreader Indexsearcher PublicIndexsearcher Getindexsearcher ()throwsException {//The first step: Create a Directory object, which is where the index inventory is placed. Directory directory = Fsdirectory.open (NewFile ("E:\\lucenesolr\\index"));//Disk//Step Two: Create a Indexreader object, you need to specify the directory object. Indexreader Indexreader =directoryreader.open (directory); //Step Three: Create a Indexsearcher o

Http://blog.sina.com.cn/s/blog_75ad10100101by7j.htmlHttp://www.cnblogs.com/zemliu/archive/2013/08/03/3234372.htmlFirst: Query_cache_type How to use query cachingIn general, we will set the Query_cache_type to on, which should be on by defaultMysql> SELECT @ @query_cache_type;+--------------------+| @ @query_cache_type |+--------------------+| On |+--------------------+Query_cache_type has 3 values of 0 for closing the

Cause Analysis and Solution of slow SQL query speed, and cause analysis of slow SQL query speed Cause Analysis and Solution for slow SQL query speed There are many reasons for slow query speed. The following are common causes:　　1. No index or no index is used (this is the most common problem of slow

50 SQL Query Techniques, query statement examples, 50 SQL statements Student (S #, Sname, Sage, Ssex) Student tableCourse (C #, Cname, T #) CurriculumSC (S #, C #, score) Orders tableTeacher (T #, Tname) Instructor tableProblem:1. query the student ID of all students whose score is higher than that of the "002" course;Copy codeThe Code is as follows:Select a. S #

When you submit a query, MySQL will analyze it to see if some optimization can be done to make it faster to process the query. This section describes how the query optimizer works. If you want to know the optimization methods used by MySQL, you can refer to the MySQL reference manual. Of course, the MySQL query optimiz

Before introducing @query comments, let's look at how to use @namedquery for named queries 1. Now the definition method on the entity class has a specific query statement @Entity @NamedQuery (name = "Task.findbytaskname", query = "Select T from Task t where T.taskname =? 1") public Class task{ } 2. After we inherit the interface, we can use this method direct

Tags: MySQL query cache query Statement statistics Query Cache state interpretationAbout MySQL ' Show global status ' output of Com_select, Queries, Questions, Qcache_hits, Qcache_inserts, Qcache_not_ Cached these state values have been a bit confusing, now through the experiment to more accurate and profound understanding.Experiment version: 5.5.39The official e

Mysql uses indexes for query optimization and mysql index Query Optimization The purpose of indexing is to improve the query efficiency. It can be analogous to a dictionary. If you want to query the word "mysql", you must locate the m letter and find the y letter from the bottom down, find the remaining SQL. If there i