I came up with a strange issue where the performance of select queries was degraded after creating missing indexes on tables. Initially, it looks like all the queries are affected but when looked into details we found that queries that have inner join with a view were affected. A view contains a couple of tables but those are not modified.
To investigate it further, I choose a simple select query and compared execution plan with the legacy server(I restored old database instance from AWS). I see that except DOP(Degree of Parallelism) everything looks same. DOP was changed from 4 to 1. i.e somehow parallelism got disabled after adding indexes.
The execution time of the query is almost double now so I assume DOP has affected it very badly. I read a couple of articles related to DOP but found nothing that can help me.
I tried providing a hint OPTION (MAXDOP 4) to query but it’s not working.
We have not changed “max degree of parallelism” configuration, it’s set to default value, so as per link, SQL Server determines parallelism itself when setting a default value. I use below query to get DOP of the server. Refer attached
select * from sys.configurations where name in ('max degree of parallelism')
SQL Server Version is Microsoft SQL Server 2014 – 12.0.4422.0 (X64) Jul 27 2015 16:56:19 Copyright (c) Microsoft Corporation Standard Edition (64-bit) on Windows NT 6.1 (Build 7601: Service Pack 1) (Hypervisor)
✓ Extra quality
ExtraProxies brings the best proxy quality for you with our private and reliable proxies
✓ Extra anonymity
Top level of anonymity and 100% safe proxies – this is what you get with every proxy package
✓ Extra speed
1,ooo mb/s proxy servers speed – we are way better than others – just enjoy our proxies!
USA proxy location
We offer premium quality USA private proxies – the most essential proxies you can ever want from USA
Our proxies have TOP level of anonymity + Elite quality, so you are always safe and secure with your proxies
Use your proxies as much as you want – we have no limits for data transfer and bandwidth, unlimited usage!
Superb fast proxy servers with 1,000 mb/s speed – sit back and enjoy your lightning fast private proxies!
99,9% servers uptime
Alive and working proxies all the time – we are taking care of our servers so you can use them without any problems
No usage restrictions
You have freedom to use your proxies with every software, browser or website you want without restrictions
Perfect for SEO
We are 100% friendly with all SEO tasks as well as internet marketing – feel the power with our proxies
Buy more proxies and get better price – we offer various proxy packages with great deals and discounts
We are working 24/7 to bring the best proxy experience for you – we are glad to help and assist you!