database-partitioning

问题 Let me explain the context first : I am building a visit tracker, with PHP and MySQL. So when a user visit a certain URL, his informations will be registered, then he will be redirected to a page. Then, when he will click on a link, I will register the information then redirect the user to his destination. So I need to WRITE informations in the database at the moment of the visit. And I need to READ and WRITE informations at the moment of the click. My problem is that I will have many many

问题 Let me explain the context first : I am building a visit tracker, with PHP and MySQL. So when a user visit a certain URL, his informations will be registered, then he will be redirected to a page. Then, when he will click on a link, I will register the information then redirect the user to his destination. So I need to WRITE informations in the database at the moment of the visit. And I need to READ and WRITE informations at the moment of the click. My problem is that I will have many many

问题 Let me explain the context first : I am building a visit tracker, with PHP and MySQL. So when a user visit a certain URL, his informations will be registered, then he will be redirected to a page. Then, when he will click on a link, I will register the information then redirect the user to his destination. So I need to WRITE informations in the database at the moment of the visit. And I need to READ and WRITE informations at the moment of the click. My problem is that I will have many many

问题 I have been reading about scalable architectures recently. In that context, two words that keep on showing up with regards to databases are sharding and partitioning . I looked up descriptions but still ended up confused. Could the experts at stackoverflow help me get the basics right? What is the difference between sharding and partitioning ? Is it true that 'all sharded databases are essentially partitioned (over different nodes), but all partitioned databases are not necessarily sharded' ?

问题 Say I have a pyspark dataframe 'data' as follows. I want to partition the data by "Period". Rather I want each period of data to be stored on it's own partition (see the example below the 'data' dataframe below). data = sc.parallelize([[1,1,0,14277.4,0], \ [1,2,0,14277.4,0], \ [2,1,0,4741.91,0], \ [2,2,0,4693.03,0], \ [3,1,2,9565.93,0], \ [3,2,2,9566.05,0], \ [4,2,0,462.68,0], \ [5,1,1,3549.66,0], \ [5,2,5,3549.66,1], \ [6,1,1,401.52,0], \ [6,2,0,401.52,0], \ [7,1,0,1886.24,0], \ [7,2,0,1886

问题 I am trying to produce a results table with the last completed course date for each course code, as well as the last completed course code overall for each employee. Below is my query: SELECT employee_number, MAX(course_completion_date) OVER (PARTITION BY course_code) AS max_course_date, MAX(course_completion_date) AS max_date FROM employee_course_completion WHERE course_code IN ('M910303', 'M91301R', 'M91301P') GROUP BY employee_number This query produces the following error: 3504 : Selected

问题 I am trying to produce a results table with the last completed course date for each course code, as well as the last completed course code overall for each employee. Below is my query: SELECT employee_number, MAX(course_completion_date) OVER (PARTITION BY course_code) AS max_course_date, MAX(course_completion_date) AS max_date FROM employee_course_completion WHERE course_code IN ('M910303', 'M91301R', 'M91301P') GROUP BY employee_number This query produces the following error: 3504 : Selected

问题 I have a table with partition based on date field. Now, I have to write a procedure to drop all partitions older than 2 months i.e. test_date is older than 2 months. How do I do it? create table test_table ( test_id number, test_date date, constraint pk_test primary key (test_id) ) partition by range (test_date) ( PARTITION pt01122012 VALUES LESS THAN (TO_DATE('01-DEC- 2012', 'DD-MON-YYYY')), PARTITION pt01022013 VALUES LESS THAN (TO_DATE('01-FEB- 2013', 'DD-MON-YYYY')), PARTITION pt01042013

问题 Is it possible to partition based on char column? After reviewing the MySQL 5.1 documentation it appears that only integer types can be used. Is this correct? Or can I use some function to convert the char into an integer? The char field in question contains a unique identifier. 回答1: Partitioning in MySQL 5.1 can only deal with integer columns (Source). You can only use a few partitioning functions on non-integer columns. For example: CREATE TABLE ti (id INT, amount DECIMAL(7,2), tr_date DATE

问题 Is it possible to partition based on char column? After reviewing the MySQL 5.1 documentation it appears that only integer types can be used. Is this correct? Or can I use some function to convert the char into an integer? The char field in question contains a unique identifier. 回答1: Partitioning in MySQL 5.1 can only deal with integer columns (Source). You can only use a few partitioning functions on non-integer columns. For example: CREATE TABLE ti (id INT, amount DECIMAL(7,2), tr_date DATE