database-performance

问题 I'm trying to create a Wikipedia DB copy (Around 50GB), but having problems with the largest SQL files. I've split the files of size in GB using linux split utility into chunks of 300 MB. e.g. split -d -l 50 ../enwiki-20070908-page page.input. On average 300MB files take 3 hours at my server. I've ubuntu 12.04 server OS and Mysql 5.5 Server. I'm trying like following: mysql -u username -ppassword database < category.sql Note: these files consist of Insert statements and these are not CSV

问题 I am using SQL Azure SQL Server for my App. The DB tier, which my app was in was working perfectly till recently and the avg DTU usage was under control. But off late, during peak hours, the DTU spikes to touch 100% consistently. Upgrading to the Next tier is an option, but first i want to figure out which query is responsible for this. Is this possible to find in Azure, which query made the DTU jump to 100%? 回答1: Simply put DTU is a blend of CPU,IO,Memory you will get based on your service

问题 I am working a java application using H2 Database in embedded mode. My Application consumes 150mb of heap memory. Problem: Steps When I load H2 database with 2 mb of data, database access is fast and heap memory size 160mb. But When I load H2 database with 30 mb of data(h2 db file size =30 mb). Then accessing the database from my application is very slow. the reason being my application heap size is hugely grown to 300mb of size hence degraded performance. I confirmed using JConsole. So my

问题 This is the second part of my question. So I have the following table, CREATE TABLE public.main_transaction ( id integer NOT NULL DEFAULT nextval('main_transaction_id_seq'::regclass), profile_id integer NOT NULL, request_no character varying(18), user_id bigint, ..... CONSTRAINT main_transaction_pkey PRIMARY KEY (id), CONSTRAINT fk_main_transaction_user_id FOREIGN KEY (user_id) REFERENCES public.jhi_user (id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION, REFERENCES public.main_profile

问题 We have this MySQL SP, which calls a nested SP. It seems it does NOT perform well under load. It is possible that this SP becomes slow under load because it calls a nested SP and uses temporary tables to pass the data to main SP? DELIMITER $$ drop procedure if exists `GeoAreaFlattened_Select`; create procedure `GeoAreaFlattened_Select`( _areas MEDIUMTEXT, _comparisonGroup varchar(21844), _parentArea varchar(21844), _areaType varchar(21844) ) begin drop temporary table if exists areas; --

问题 My server application makes multiple connections to MySQL through separate threads. Each connection fires a SELECT query and fetches result which the application then caters back to its connected users. I am using InnoDB. To my surprise I found it a very weird that if I increase number of connections to MySQL, query performance deteriorates and result fetch time also increases. Below is a table showing same. This data is produced when I had 3333 records in MySQL table and the SELECT query

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed last year . I'm building a simple android RPG. Each player has access to a maximum of about 50 soldiers. Each soldier has some stats (class, hp, attack, etc), and three inventory slots. There will be only about 100 items in the game to fill these inventory slots. I was hoping to set up a relational database that would have a

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed last year . I'm building a simple android RPG. Each player has access to a maximum of about 50 soldiers. Each soldier has some stats (class, hp, attack, etc), and three inventory slots. There will be only about 100 items in the game to fill these inventory slots. I was hoping to set up a relational database that would have a

问题 Is it possible to alter an existing non clustered index to include more columns as a part of Covered columns. e.g. ALTER INDEX IX_NC_TableName_ColumnName FOR TableName(ColumnName) INCLUDE(Col1, Col2, Col3) Want to include Col4 in above index. What will be the impact of adding this column? Will there be fragmentation or anything else? 回答1: The cost of an additional included column will be increased storage and potentially fragmentation. Fragmentation will increase slightly compared to the old

问题 Hi i have this large oracle hibernate web applications and it seems to give this error ORA-01795: maximum number of expressions in a list is 1000 and i need a java code tested by someone as a hibernate user defined component to add to my search java classes in my screen as easy as possible could someone have such tested component? 回答1: i tried this below code from link and it seem to work beautifully i will paste the code in-case the link were broken in future. Keep it Simple Keep it Smile :)