September 25, 2012 at 12:50 am
Hi,
When we insert the data into a table, what happened exactly(process)?
How the data will be inserted? For any modifications sql server uses t-log right? How the t-log will be committed to data pages?
Thanks,
🙂
September 25, 2012 at 1:51 am
The transaction log is used for all modifications to guarantee atomicity, durability and consistency. Read Gail's thorough article.
http://www.sqlservercentral.com/articles/Administration/64582/
September 25, 2012 at 2:52 am
The transaction log records aren't committed to data pages. The data modification is made to the data pages (in memory) and then logged into the transaction log. The only time you get replay from the log is in database recovery or restores (or on the mirror DB in database mirroring).
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
September 25, 2012 at 3:24 am
GilaMonster (9/25/2012)
The transaction log records aren't committed to data pages. The data modification is made to the data pages (in memory) and then logged into the transaction log. The only time you get replay from the log is in database recovery or restores (or on the mirror DB in database mirroring).
The data modification is made to the data pages (in memory) and then logged into the transaction log.
That means
1. Sql server fetches the table related data pages to memory (What is the memory in this case is it RAM?)
Q. How many pages will be fetched to Memory?
Q2. How does server knows that the pages are related to a table?
if i am wrong can u correct me, Can you tell me the process of insertion?
Thanks alot
🙂
September 25, 2012 at 4:25 am
There are scads and scads of processes that take place when you insert data. I'd suggest getting a copy of Kalen Delaney's book SQL Server Internals. That covers the process in wonderful detail much better than you're going to get in a simple forum post.
May I ask, what specifically are you trying to understand about it? Are you hitting some type of problem?
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September 25, 2012 at 4:36 am
SQL* (9/25/2012)
Q. How many pages will be fetched to Memory?
As many as are needed for the query
Q2. How does server knows that the pages are related to a table?
In short, the allocation pages (or which there are many kinds) and the system tables.
Read Kalen's book, read Paul Randal's blog.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
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