database-performance

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 based on random parameters given to it fetches around 450 records out of them. Each record has around 10

I can't seem to figure out why SQL Server is taking a completely different execution plan when wrapping my code in an ITVF. When running the code inside of the ITVF on its own, the query runs in 5 seconds. If I save it as an ITVF, it will run for 20 minutes and not yield a result. I'd prefer to have this in an ITVF for code reuse. Any ideas why saving code as an ITVF would cause severe performance issues? CREATE FUNCTION myfunction ( @start_date date, @stop_date date ) RETURNS TABLE AS RETURN ( with ad as ( select [START_DATE] ,[STOP_DATE] ,ID ,NAME ,'domain1\' + lower(DOMAIN1_NAME) collate

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 table for soldiers, a table for items owned, and a few other various tables. Speed is my main concern. SQLite is the obvious first choice. However, it seems to be very bulky and geared towards databases with 1000's of rows. Is there a better option for small databases? I don't need

Objective Verify if it is true that insert records without PK/index plus create thme later is faster than insert with PK/Index. Note The point here is not about indexing takes more time (it is obvious), but the total cost (Insert without index + create index) is higher than (Insert with index). Because I was taught to insert without index and create index later as it should be faster. Environment Windows 7 64 bit on DELL Latitude core i7 2.8GHz 8G memory & SSD HDD Oracle 11G R2 64 bit Background I was taught that insert records without PK/Index and create them after insert would be faster than

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? The cost of an additional included column will be increased storage and potentially fragmentation. Fragmentation will increase slightly compared to the old index due to the increased leaf node size (assuming keys are not incremental) and if updates to the new

Here is the scenario I find myself in. I have a reasonably big table that I need to query the latest records from. Here is the create for the essential columns for the query: CREATE TABLE [dbo].[ChannelValue]( [ID] [bigint] IDENTITY(1,1) NOT NULL, [UpdateRecord] [bit] NOT NULL, [VehicleID] [int] NOT NULL, [UnitID] [int] NOT NULL, [RecordInsert] [datetime] NOT NULL, [TimeStamp] [datetime] NOT NULL ) ON [PRIMARY] GO The ID column is a Primary Key and there is a non-Clustered index on VehicleID and TimeStamp CREATE NONCLUSTERED INDEX [IX_ChannelValue_TimeStamp_VehicleID] ON [dbo].[ChannelValue] (