I am trying to migrate my ASP (IIS) +SQLServer application from SQL Server Express Edition to Azure SQL database. Currently, we only have one dedicated server with both IIS and SQL express edition on it. The planned setup will be ASP (IIS) on an Azure virtual machine and Azure SQL database.
Per my search on google, it seems SQL server Express Edition has performance issues which are resolved in standard and enterprise edition. The DTU calculator indicates that I should move to 200 DTUs. However, that is based on test run on SQL Express edition setup with IIS on the same dedicated server.
Some more information:
The database size is around 5 GB currently including backup files.
Total users are around 500.
Concurrent usage is limited, say around 30-40 users at a time.
Bulk usage happens for report retrieval during a certain time frame only by a limited number of users.
I am skeptical to move to 300DTUs given the low number of total users. I am initially assuming 100 DTUs is good enough but looking for some advice on someone who has dealt with this before.
Database size and number of users isn't a solid way to estimate DTU usage. A poorly indexed database with a handful of users can consume ridiculous amounts of DTUs. A well-tuned database with lively traffic can consume a comparatively small number of DTUs. At one of my clients, we have a database that handles several million CRUD ops per day over 3,000+ users that rarely breaks 40DTUs.
That being said, don't agonize over your DTU settings. It is REALLY easy to monitor and change. You can scale up or scale down without interrupting service. I'd make a best guess, over-allocate slightly, then move your allocated DTUs up or down based on what you see.
it seems SQL server Express Edition has performance issues
This is not correct.There are certain limitations like 10GB size,one core CPU and some features are disabled ..
I am initially assuming 100 DTUs is good enough but looking for some advice on someone who has dealt with this before.
I would go with the advice of DTU calculator,but if you want to go with 100 DTU's,i recommend going with it ,but consistently evaluate performance..
Below query can provide you DTU metrics in your instance and if any one of the metrics is consistently over 90% over a period of time,i would try to tune that metric and finally upgrade to new tier,if i am not successfull
DTU query
SELECT start_time, end_time,
(SELECT Max(v)
FROM (VALUES (avg_cpu_percent), (avg_physical_data_read_percent), (avg_log_write_percent)) AS value(v)) AS [avg_DTU_percent]
FROM sys.resource_stats
WHERE database_name = '<your db name>'
ORDER BY end_time DESC;
-- Run the following select on the Azure Database you are using
SELECT
max (avg_cpu_percent),max(avg_data_io_percent),
max (avg_log_write_percent)
FROM sys.resource_stats
WHERE database_name = 'Database_Name'
Related
On a normal SQL server we can tell it how to grow. The default is 10% each time, so the database grows by 10% its current size. Do we have any insight on how the Azure SQL database is growing other than it grows automatically?
Azure SQL server would allow us to configure the database to grow in fixed chunks e.g. 20 MB?
thanks,
sakaldeep
You can use PowerShell, T-SQL, CLI. the portal to increase or decrease the maximum size of a database but Azure SQL Database does not support setting autogrow. You can vote for this feature to be available in the future on this URL.
If you run the following query on the database, you will see the growth is set to 2048 KB.
SELECT name, growth
FROM sys.database_files;
I have to decide to use an Azure SQL Data Warehouse or a SQL Data warehouse based on Microsoft SQL Server virtualized on a VM.
The problem what i do not understand is the MAX CONCURRENT QUERIES LIMITATION TO 32. The same for the Azure SQL Database is 6400.
To be honest when i want to use the Azure Data Warehouse in an Enterprise environment the 32 concurrent queries are laughable or i do not understand it.
Lets assume a company with 10.000 Employees worldwide and i set up a Azure Data Warehouse for reporting purpose where lets assume 250 permanently are querying from or additional 250 employees are working with a business app which uses data from the Data Warehouse. How should this work without extreme performance lacks?
This isn't the issue that you might think.
First, the limit is now 128. (https://learn.microsoft.com/en-us/azure/sql-data-warehouse/memory-and-concurrency-limits#gen2-1)
Second, this is well above the concurrency of the next most concurrent single cluster warehouse. I've often wondered what marketing mistake was made by Microsoft that concurrency is seen as a limitation on ASDW, but rarely mentioned for less concurrent competitors.
Third, the best way to serve thousands of concurrent query users (ie, dashboards) is through PowerBI hybrid queries, and (potentially) Azure Analysis Services. This gives extremely high concurrency and interactivity.
Perhaps the best evidence I can give is that I work with Azure SQL Data Warehouse customers on a daily basis. I often get questions like this when a customer is first exposed to ASDW, but I never get questions about concurrency by the time they're in production. In other words, the issue of "concurrency" just isn't important for most customers.
I am working on a solution architecture and am having hard time choosing between Azure SQL DB or SQL DW.
The current scope involves around developing real-time BI reporting solution which is based on multiple sources. But in the long run the solution may be extended into a full fledged EDW and Marts.
I initially thought of using SQL DW so that for future scope the MPP capabilities could be used. But when I spoke to a mate who recently used SQL DW, he explained that the the development in SQL DW is not similar to SQL DB.
I have worked previously on Real Time reporting with no scope for EDW and we successfully used SQL DB. With this as well we can create Facts and Dimension and Marts.
Is there a strong case where I should be choosing SQL DW over SQL DB?
I think the two most important data points you can have here is the volume of data you're processing and the number of concurrent queries that you need to support. When talking about processing large volume data, and by large, I mean more than 3tb (which is not even really large, but large enough), then Azure SQL Data Warehouse becomes a juggernaut. The parallel processing is simply amazing (it's amazing at smaller volumes too, but you're paying a lot of money for overkill). However, the one issue can be the simultaneous query limit. It currently has a limit of 128 concurrent queries with a limit of 1,000 queries queued (read more here). If you're using the Data Warehouse as a data warehouse to process large amounts of data and then feed them into data marts where the majority of the querying takes place, this isn't a big deal. If you're planning to open this to large volume querying, it quickly becomes problematic.
Answer those two questions, query volume and data volume, and you can more easily decide between the two.
Additional factors can include the issues around the T-SQL currently supported. It is less than traditional SQL Server. Again, for most purposes around data warehousing, this is not an issue. For a full blown reporting server, it might be.
Most people successfully implementing Azure SQL Data Warehouse are using a combination of the warehouse for processing and storage and Azure SQL Database for data marts. There are exceptions when dealing with very large data volumes that need the parallel processing, but don't require lots of queries.
The 4 TB limit of Azure SQL Database may be an important factor to consider when choosing between the two options. Queries can be faster with Azure SQL Data Warehouse since is a MPP solution. You can pause Azure SQL DW to save costs with Azure SQL Database you can scale down to Basic tier (when possible).
Azure SQL DB can support up to 6,400 concurrent queries and 32k active connections, where Azure SQL DW can only support up to 32 concurrent queries and 1,024 active connections. So SQL DB is a much better solution if you are using something like a dashboard with thousands of users.
About developing for them, Azure SQL Database supports Entity Framework but Azure SQL DW does not support it.
I want also to give you a quick glimpse of how both of them compare in terms of performance 1 DWU is approximately 7.5 DTU (Database Throughput Unit, used to express the horse power of an OLTP Azure SQL Database) in capacity although they are not exactly comparable. More information about this comparison here.
Thanks for you responses Grant and Alberto. The responses have cleared a lot of air to make a choice.
Since, the data would be subject to dash-boarding and querying, I am tilting towards SQL Database instead of SQL DW.
Thanks again.
Here is the situation, we have intense requests demands on our sql azure database, so we decided to replicate the database, one for read (sql queries) and one for writing (updates) given that we have to move to premium service so the database cost in creases from pretty 300 dollars to 2000 dollars and that affect dramatically the project rentability, so is there any other solutions to optimise that cost
Thank you
Are any of these options viable for you?
Running traditional SQL in an Azure VM (not limited to Azure SQL DTU model)
Using a message queue to move writes to an eventual consistent model using competing consumers
Create de-normalized/pre-computed tables (i.e. SELECT INTO) for the read operations during low-use times
Use materialized and/or indexed views for reads (reduced CPU/DTU usage)
Push data into Azure Table or DocumentDB for reads
Just ideas, but I feel your pain. The DTU thing is both a blessing and a curse.
I'm currently running an instance of MS SQL Server 2014 (12.1.4100.1) on a dedicated machine I rent for $270/month with the following specs:
Intel Xeon E5-1660 processor (six physical 3.3ghz cores +
hyperthreading + turbo->3.9ghz)
64 GB registered DDR3 ECC memory
240GB Intel SSD
45000 GB of bandwidth transfer
I've been toying around with Azure SQL Database for a bit now, and have been entertaining the idea of switching over to their platform. I fired up an Azure SQL Database using their P2 Premium pricing tier on a V12 server (just to test things out), and loaded a copy of my existing database (from the dedicated machine).
I ran several sets of queries side-by-side, one against the database on the dedicated machine, and one against the P2 Azure SQL Database. The results were sort of shocking: my dedicated machine outperformed (in terms of execution time) the Azure db by a huge margin each time. Typically, the dedicated db instance would finish in under 1/2 to 1/3 of the time that it took the Azure db to execute.
Now, I understand the many benefits of the Azure platform. It's managed vs. my non-managed setup on the dedicated machine, they have point-in-time restore better than what I have, the firewall is easily configured, there's geo-replication, etc., etc. But I have a database with hundreds of tables with tens to hundreds of millions of records in each table, and sometimes need to query across multiple joins, etc., so performance in terms of execution time really matters. I just find it shocking that a ~$930/month service performs that poorly next to a $270/month dedicated machine rental. I'm still pretty new to SQL as a whole, and very new to servers/etc., but does this not add up to anyone else? Does anyone perhaps have some insight into something I'm missing here, or are those other, "managed" features of Azure SQL Database supposed to make up the difference in price?
Bottom line is I'm beginning to outgrow even my dedicated machine's capabilities, and I had really been hoping that Azure's SQL Database would be a nice, next stepping stone, but unless I'm missing something, it's not. I'm too small of a business still to go out and spend hundreds of thousands on some other platform.
Anyone have any advice on if I'm missing something, or is the performance I'm seeing in line with what you would expect? Do I have any other options that can produce better performance than the dedicated machine I'm running currently, but don't cost in the tens of thousand/month? Is there something I can do (configuration/setting) for my Azure SQL Database that would boost execution time? Again, any help is appreciated.
EDIT: Let me revise my question to maybe make it a little more clear: is what I'm seeing in terms of sheer execution time performance to be expected, where a dedicated server # $270/month is well outperforming Microsoft's Azure SQL DB P2 tier # $930/month? Ignore the other "perks" like managed vs. unmanaged, ignore intended use like Azure being meant for production, etc. I just need to know if I'm missing something with Azure SQL DB, or if I really am supposed to get MUCH better performance out of a single dedicated machine.
(Disclaimer: I work for Microsoft, though not on Azure or SQL Server).
"Azure SQL" isn't equivalent to "SQL Server" - and I personally wish that we did offer a kind of "hosted SQL Server" instead of Azure SQL.
On the surface the two are the same: they're both relational database systems with the power of T-SQL to query them (well, they both, under-the-hood use the same DBMS).
Azure SQL is different in that the idea is that you have two databases: a development database using a local SQL Server (ideally 2012 or later) and a production database on Azure SQL. You (should) never modify the Azure SQL database directly, and indeed you'll find that SSMS does not offer design tools (Table Designer, View Designer, etc) for Azure SQL. Instead, you design and work with your local SQL Server database and create "DACPAC" files (or special "change" XML files, which can be generated by SSDT) which then modify your Azure DB such that it copies your dev DB, a kind of "design replication" system.
Otherwise, as you noticed, Azure SQL offers built-in resiliency, backups, simplified administration, etc.
As for performance, is it possible you were missing indexes or other optimizations? You also might notice slightly higher latency with Azure SQL compared to a local SQL Server, I've seen ping times (from an Azure VM to an Azure SQL host) around 5-10ms, which means you should design your application to be less-chatty or to parallelise data retrieval operations in order to reduce page load times (assuming this is a web-application you're building).
Perf and availability aside, there are several other important factors to consider:
Total cost: your $270 rental cost is only one of many cost factors. Space, power and hvac are other physical costs. Then there's the cost of administration. Think work you have to do each patch Tuesday and when either Windows or SQL Server ships a service pack or cumulative update. Even if you don't test them before rolling out, it still takes time and effort. If you do test, then there's a second machine and duplicating the product instance and workload for test.
Security: there is a LOT written about how bad and dangerous and risky it is to store any data you care about in the cloud. Personally, I've seen way worse implementations and processes on security with local servers (even in banks and federal agencies) than I've seen with any of the major cloud providers (Microsoft, Amazon, Google). It's a lot of work getting things right then even more work keeping them right. Also, you can see and audit their security SLAs (See Azure's at http://azure.microsoft.com/en-us/support/trust-center/).
Scalability: not just raw scalability but the cost and effort to scale. Azure SQL DB recently released the huge P11 edition which has 7x the compute capacity of the P2 you tested with. Scaling up and down is not instantaneous but really easy and reasonably quick. Best part is (for me anyway), it can be bumped to some higher edition when I run large queries or reindex operations then back down again for "normal" loads. This is hard to do with a regular SQL Server on bare metal - either rent/buy a really big box that sits idle 90% of the time or take downtime to move. Slightly easier if in a VM; you can increase memory online but still need to bounce the instance to increase CPU; your Azure SQL DB stays online during scale up/down operations.
There is an alternative from Microsoft to Azure SQL DB:
“Provision a SQL Server virtual machine in Azure”
https://azure.microsoft.com/en-us/documentation/articles/virtual-machines-provision-sql-server/
A detailed explanation of the differences between the two offerings: “Understanding Azure SQL Database and SQL Server in Azure VMs”
https://azure.microsoft.com/en-us/documentation/articles/data-management-azure-sql-database-and-sql-server-iaas/
One significant difference between your stand alone SQL Server and Azure SQL DB is that with SQL DB you are paying for high levels of availability, which is achieved by running multiple instances on different machines. This would be like renting 4 of your dedicated machines and running them in an AlwaysOn Availability Group, which would change both your cost and performance. However, as you never mentioned availability, I'm guessing this isn't a concern in your scenario. SQL Server in a VM may better match your needs.
SQL DB has built in availability (which can impact performance), point in time restore capability and DR features. You have the option to scale up / down your DB based on your usage to reduce the cost. You can improve your query performance using Global query (shard data). SQl DB manages auto upgrades and patching and greatly improves the manageability story. You may need to pay a little premium for that. Application level caching / evenly distributing the load, downgrading when cold etc. may help improve your database performance and optimize the cost.