#Cloudberry server maintenance expired Offline
#Cloudberry server maintenance expired download

The feature is called: wait at low priority. With SQL Server 2014, Microsoft has shipped a new functionality which could be very useful in relieving our online index operations. Today online index rebuild might take 1 hour, but tomorrow might need 10 hours or even more! Online maintenance is holding locks at the beginning and at the end of our operations, which might be problematic especially on critical and busy production servers. This is another unpredictable time interval at the end of our procedure. Oh no! We are waiting one more time, but for a Schema Modification lock to be granted so the SQL can complete the rebuild operation. Rollback the transaction holding the lock (session 58 in my case) and immediately start it again (you have several seconds to do this before the index rebuild operation finishes). This might take several seconds or minutes, but in some situations even hours! This makes the operation unpredictable as we cannot say for sure when the maintenance operation will be able to take this lock and start its work. Session 57 (online index rebuild) is waiting for all of the exclusive locks to be released.

#Cloudberry server maintenance expired download

Download database вЂњAdventureWorksDW2012вЂќ from here and attach it.

In order this to happen, we need a Schema Modification lock is not compatible with any locks.

Final phase вЂ“ declare to SQL that the new index is ready.

Typically you should not see any locks here

Build phase вЂ“ the phase of populating data into the new index.

Preparation phase вЂ“ you need to take at this point a Share lock for the row versioning and the lock is not compatible with an exclusive lock.

Online operations are divided into three phases (if you are keen on learning more details, please check this whitepaper): Are they really online?Д«efore we go into more details, keep in mind that this is an Enterprise edition feature only. The interesting point is when it comes to online operations. I guess this is very intuitive so we did not reinvent the wheel.

#Cloudberry server maintenance expired Offline

We now know for sure that offline operations are really offline. The only exception to this rule is that we are allowed to read data from the table while a non-clustered index is being created offline. query (session 63) because the offline index rebuild on the non-clustered index is blocking our session (session 64):Д®ven this was a non-clustered index, we were not able to read our data while the rebuild operation was taking place. This time, we are not seeing any rows immediately coming from a. query and run it and observe the locks with the query c. LetвЂ™s start the index rebuild from b., then switch to a. If we run the query from a., it will work and return the result for around 1 minute without any blockings. LetвЂ™s test this with one simple scenario:Д¬reate a test database to play with one simple table and insert some data with deliberately skipping some values to produce page splits and larger fragmentation: Cannot change the initial fill factor used during index creation.Not efficient when you have a large fragmentation as it is only reorganizing the leaf-level pages.So far so good! However there are several major drawbacks: This operation is always online, uses minimal system resources, honors the fill factor that has been used during the creation of the index (common misconception is that reorganize operation does not take into account fill factor at all) and if you kill it due to any reason, the work that has been done would still persist.

One of the possibilities that we have in SQL Server to keep our indexes defragmented, is the index reorganize operation. I am not going to convince you how important is to keep our indexes in a good shape, so we are directly jumping into how we can maintain them. We are taking off with the indexes in our databases. In this article, we will take a look at the different maintenance operations we have in SQL Server and how we can optimize them and take the maximum out of each. However, this aspect is frequently underestimated which could lead to performance problems and respectively angry, unhappy customers.

Database maintenance is very important, a critical part of our database administratorsвЂ™ daily tasks.