Tag：plan
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Time：2021-10-22
1. Modify the storage location of log files: open IIS log 2. Of course, we can delete the log file manually. The more convenient way is to create a batch file (for example, deletelog. Bat), which contains the following contents: Create a new text document – copy the following code – save and modify […]
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Time：2021-10-19
Introduction: analyticdb for MySQL provides users with efficient, real-time, feature rich and intelligent “SQL intelligent diagnosis” and “SQL intelligent tuning” functions, provides users with ideas, directions and specific methods for SQL performance tuning, reduces users’ use costs and improves users’ efficiency in using ADB. SQL is a simple and easy-to-use business logic expression language, but […]
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Time：2021-10-11
MySQL will select the most appropriate execution plan for all our query statements. This execution plan shows how to execute the query next. In our daily work, we can add the explain keyword in front of the SQL statement to view the specific execution plan. for instance: This is the most direct result we see […]
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Time：2021-10-10
First, query the status of plan events in SQL: Show variables like ‘event_ scheduler’If off is returned, it means that the current status is closed. If on, the planned task has been opened.Find the my.ini file in the MySQL program directory and add an item: event_ scheduler = 1After saving, restart the MySQL service, which […]
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Time：2021-10-5
This article was first published on November 21, 2016 at 09:43:07 framework Greenplum adopts the architecture of share nothing and gives good play to the role of cheap PC. Since then, I / O is no longer the bottleneck of DW (data warehouse). On the contrary, the pressure on the network will be much greater. […]
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Time：2021-9-9
Support vector machine optimization problem (convex optimization problem, quadratic programming problem) 1. Minimize: \ dfrac {1} {| w | ^ 2} = \ dfrac {1} {2} (W 1 ^ 2 + W 2 ^ 2 +… + W n ^ 2)2. Subject to: y_ i[W^TX_i + b]\geq 1( i = 1\sim N )The optimization problem […]
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Time：2021-9-1
How difficult is dynamic programming? Dynamic programming is a word borrowed from other industries. Its general meaning is to divide one thing into two parts firstSeveral stagesAnd then through thetransferAchieve the goal. Since the transfer direction is usually multiple, it is necessary at this timepolicy decisionSelect a specific transfer direction. What dynamic programming needs to […]
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Time：2021-8-6
Today, let’s share some common SQL errors (improper) usage of MySQL. As a beginner, we probably didn’t notice these problems when writing SQL, resulting in low efficiency of written SQL statements, so we can also introspect ourselves. 1. Limit statement Paging query is one of the most common scenarios, but it is also often the […]
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Time：2021-8-5
–Explain view SQL execution plan EXPLAIN PLAN FOR select count(*) from steven.AWEN_OGG_TEST; select * from table(dbms_xplan.display()); –View the execution plan in AWR and cursor select * from table(dbms_xplan.display_awr(‘&sqlid’)); select * from table(dbms_xplan.display_cursor(‘&sqlid’)); –View the execution plan in memory in the game agent select ‘| Operation |Object Name | Rows | Bytes| Cost |’ as “Explain […]
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Time：2021-7-20
Today, let’s do a test using sqlpatch fixed execution plan 1. Use table for test create table tab2(c1 number, c2 number, c3 varchar2(10)); declare a number; begin a := 1; for i in 1 .. 50 loop for j in 1 .. 100 loop insert into tab2 values(a,j,’a’); commit; a := a+1; end loop; end […]
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Time：2021-7-15
Today, I’d like to talk about another method of fixed execution plan: sqlprofile. 1. Obtain the implementation plan without hint. SQL> conn test/test It’s going to go on. SQL> explain plan for select * from tab2 where c2=2; The analysis of the meaning of the word されました. SQL> select * from table (dbms_xplan.display(format=>’advanced’)); PLAN_TABLE_OUTPUT ———————————————————————————————————————— […]
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Time：2021-7-6
[introduction]: an open source library for path planning algorithms commonly used in robotics, as well as an intuitive demonstration of the running process by moving pictures. The library has not been open for a long time and has 1200 + stars in GitHub. brief introduction In the field of robot research, given a specific task, […]
