Running queries via REST BaseX api is just instantaneous compared to running it via Queries screen in DBA console which uses RESTXQ. Has anyone faced this issue? or please could you share your experience resolving it. Second question was do we need to open a particular DB before running a query or is there an option to allow Database be left open at all times.
Related
We created an ASP.NET MVC web application using C#, and we're using SQL Server database and hosted on AWS server.
The issue is when we increase the load on the web application, then the whole application goes down. And when check monitor graph on AWS then find out that CPU utilization is very high like 70 to 80%. Normally its like 20 to 25%. Also there is strange issue that according to UTC date at 5AM its again started working properly.
I tried to optimize my stored procedures and increase AWS server load capacity. Checked monitor activity in SQL Server. But did not found why everyday getting down at load time. What might be the reason behind them?
Here are some related please review once
CPU Utilization Graph.
Database Activity Monitor
Please let me know how to find out the cause of these issues.
Providing basic insights here : The three most common causes of server slowdown: CPU, RAM, and disk I/O. CPU use can slow down the host as a whole and make it hard to complete tasks on time. Top and sar are two tools you can check the CPU.
As you are using stored proedure , if it might take more time in querying then this will results in IO Waits which utilmately results down in server slowdown. This is a basic troubleshooting doc .
I am using a DB2 v10.5, and I am pushing messages into the database I created using a gateway. Is there a way to check the DB2 sql logs for actual SQL operation executed?, ie how many rows were fetched etc? While googling, I find these logs inside the DB2 server in the DIAGPATH /db2/db2inst1/sqllib/db2dump/ but I don't see any SQL messages in there.
I have been checking DB2 guides as well but any ideas to help me on this is greatly appreciated. Thank you.
Activity event monitoring
Briefly:
It acts like "logger" for executed statements. The information is written to the tables of such an event monitor for sessions with such a "logging" enabled.
There is also the package cache. This holds aggregate metrics for all executions of a statement that are still in the package cache (entries get evicted from the cache as newer statement arrive). MON_GET_PKG_CACHE_STMT
You can also use the Db2 Database Management Console which is
A new browser-based console that helps you administer, monitor, manage and optimize the performance of IBM Db2 for Linux, UNIX and Windows databases.
and which itself collects data via functions such as MON_GET_PKG_CACHE_STMT and Activity Event Monitors
I'm looking into creating a SQL Server database and then creating some T-SQL scripts which simulate stress/ a load on the database. Which I can then investigate using windows performance monitor, to highlight the causes of the load, and how to fix it. The aim of this is to train an ability to investigate database performance problems and how to fix them.
I'm new to database administration but I can't seem to find many resources/information on performance and creating fake loads to test performance.
Any help would be appreciated.
Take a look at
SQL Query Stress - allows you to simulate load by executing queries repeatedly.
Diskspd - test I/O subsystem
If you need some data to test against you are also free to download the StackOverflow database and put it on your test server. Here's a LINK to a post on how to download the database.
I'm experiencing periodical Azure SQL Database connection slow downs. As recommended in Wait statistics, or please tell me where it hurts article I ran sys.dm_db_wait_stats (analogue of sys.dm_os_wait_stats for Azure SQL Database) aggregation script which show me that longest waits are of type XE_FILE_TARGET_TVF. Average wait time is 54 seconds.
XE_FILE_TARGET_TVF didn't mentioned in documentation as in any other online resources that I know. I suspect that "XE" means "Extended Events", "TVF" is "table-valued functions", "FILE_TARGET" is probably indicator that something is being written to some file.
So, what kind of wait it is?
Use Azure SQL Database Query Performance Insight for troubleshooting SQL Azure DBs. To begin with, wait stats alone are not a correct performance troubleshooting approach. Read How to analyse SQL Server performance for a more thorough approach, learn to analyze also where the CPU is spent, not only where the elapsed time is spent waiting. Aggregate wait stats are often misleading, filtering out the 'benign' wait stats is a chasing the red lights game.
Unfortunately not everything is actionable in SQL Azure DB environment. Start with the Query Performance Insight to see if you can correlate the performance issues with queries issued by your app. Use the SQL Database Index Advisor to get index recommendations for your workload.
If you cannot find the application problems and suspect this is caused by the platform, you will have to open a support case. Twitting #AzureSupport is very effective in getting help.
To answer your question: a lot of Azure SQL DB monitoring relies on Extended Events and they store data to files. This specific wait stat is unlikely to be related to the cause of your performance problems.
I believe that it's a async process so possibly nothing to worry around and could be a red herring. However I think this is a fabric related task behind the DB. Does this event seem to be consistently causing you issues?
In our college, we are conducting a contest, which is in the form of Multiple choice questions.
For that we are using VB as a front-end , MS Access as a back-end.
Ref:
The Application VB 6 runs with no problem and the participant entry is added into the database along with their scores, when 1 or 2 clients access the database simultaneously.
Problem:
But when more than 2 clients access the database simultaneously, the Application crashes.
1.In some clients, we are getting runtimeerror printing some large negative value with a
message "Operations query cannot modify the database".
2.In some clients, the VB 6.0 crashes and closes suddenly.
These errors occurs when we are tried to access the database using
OK,SUBMIT buttons.
Could you tell me why this error occurs and how can I correct it.
My Questions are..
1.Is giving the burden of all clients to a single laptop is the problem here?If there is some other problem please explain it.
2.Why I am getting the error as "Operation query cannot modify database", If so then how it works when 1 or 2 clients access the database simultaneously.
Access databases (and other directly file-based DBs) are not really built for multi-access. There are some facilities in place to help it work, but in my experience, it is quite unreliable.
You need a database server running, which can allow multiple clients to the same database simultaneously. A free option is MySQL. There is also a free version of Microsoft SQL Server available.
"Operation query cannot modify database"
Badly designed Access databases can have issues with users trying to modify records if they don't have defined Primary keys. This is especially true when multiple people are accessing because it literally can't tell which record to modify if two people try to do the same thing. Sometimes it will let you insert but not update.
Further if you are looking for performance, Access is just the wrong tool. It has very little in the way of performance tuning options or abilities. SQl Server Express or mySQl would have more things available to diagnose and fix a performance issue.