Hi all. May I know how to read the following output of DBCC PAGE number 3 GAM page. ?
which mean extent 0 - 26432 are allocated ?
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DBCC Page GAM page
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SQL Server 2019 : Memory-Optimized tempdb Metadata
I am reading the following docs:
https://docs.microsoft.com/en-us/sql/relational-databases/databases/tempdb-database?view=sql-server-ver15#memory-optimized-tempdb-metadata
it mention this feature for SQL Server 2019
.......memory-optimized tempdb metadata, which effectively removes this bottleneck and unlocks a new level of scalability for tempdb-heavy workloads. In SQL Server 2019 (15.x), the system tables involved in managing temporary table metadata can be moved into latch-freenon-durable memory-optimized tables..........
So I just curious
1. I have done some test , after enable this features, all the PAGELATCH_EX gone , for resource of page of metadata table sys sysschobjs. So after enable the feature , the page of sysschobjs do not need a PAGELATCH_ to lock this resource when multiple session are modifying it ? or it's just too fast to release the lock that I can't notice it ?
2 what mean non-durable?
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max worker thread
If I have a server have 16 cores , 64 bits, can I tune max worker thread (instance setting) to 1000 ?
And if calculating max worker thread will be using physical core or logical core or the CPU ?
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2016 SP2 Azure VM TDE database backup causing huge issues
hi folks:
Our Azure VM SQL is using 2016 SP2 entCU8. We have a list of databases with TDE enabled and backup was using compression with the following parameters
WITH FORMAT, COMPRESSION, MAXTRANSFERSIZE = 4194304, BLOCKSIZE = 65536, STATS = 1
for smaller databases less than 1TB , they went through without an issue.
For bigger dbs over 1TB, one is with 2TB and the other was 8TB. It was causing huge I/O async waitype to the point it caused
locks to many processes and we have to stop it.
has anyone seen such issue before and any suggestions?
We are also in contact with MSFT premier support and initial words was that at one point of time, disk performance dropped dramatically and we've asked all teams but they said no schedule jobs running during that backup time . We've verified and confirmed.
One thing I noticed that these two big databases, VLF size is over 20G though Active VLF size is under 200MB
I know that it is not recommended to backup tlog with over 4G VLF, does that apply to full back?
Cheers
HS
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SQL Server wait: LATCH vs PAGELATCH ?
I know pagelatch means waiting a latch to access a page in memory . So what about LATCH ? Any example ?
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FileSystem
Hi,
We are migrating from SQL Server 2016 which is on ReFS/64k block size. We have OLTP and OLAP system ranging from 10 to 15TB sizes.
What is the best practice? Shall i continue same ReFS with 64k block size or any other recommendation?
Thanks
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Logshipping from 2012 to 2019
Is it possible to ship Logshipping from 2012 to 2019?
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The network name cannot be found at System.Data.SqlTypes.SqlFileStream.OpenSqlFileStream
Hi,
I have 3 Node SQL AOAG Cluster.
Recently , while trying to check the Application status , I started seeing below error in previous primary (AG Replica1) where as the status is working in now primary (previous secondary AG Replica2). Please share some thoughts on the issue below.
Internal error occurred in sync. Please see details for contextual information.
Organisation.RE.APP.Sync.Common.Exceptions.SyncCriticalSqlException: Critical issue requires administrative attention. ---> System.REta.SqlClient.SqlException: The network name cannot be found ---> System.ComponentModel.Win32Exception: The network
name cannot be found
at System.REta.SqlTypes.SqlFileStream.OpenSqlFileStream(String path, Byte[] transactionContext, FileAccess access, FileOptions options, Int64 allocationSize) at System.REta.SqlTypes.SqlFileStream..ctor(String path, Byte[] transactionContext, FileAccess
access, FileOptions options, Int64 allocationSize) at System.REta.SqlTypes.SqlFileStream..ctor(String path, Byte[] transactionContext, FileAccess access) at Organisation.RE.APP.Framework.Implementation.REta.SqlFileStreamHelper.GetSqlFileStream(String
PstrFileStreamPath, Byte[] PabyTransactionContext, FileAccess PeFileAccess)
CreateChangeBatch: Critical issue requires administrative attention.
The network name cannot be found
The network name cannot be found
Best Regards,SQLBoy
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SQL Server processes sqlserv.exe memory
I have check the following memory usage for the sqlserver
so how to derive 4591.1MB usage on the first screen ?
ccommit size and working set (memory) have what difference ?
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Memory usage
what are
commited ? Cached? Paged pool and non-paged pool?
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SQL Server soft-numa
If the server has 2 socket and each has 8 phyiscal core per each. and enable hardware numa. So SQL Server 2016 will still do the auto-software numa configuration during startup ?
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Multipage allocation vs Large Pageallocation
May I know Multipage allocation vs Large Pageallocation are the same concept ?
Any example of what type of Multipage allocation are?
I check in my sys.dm_os_memory_clerks that column page_sizes_in_bytes are all 8192 .
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sys.dm_os_memory_pools pool_id
https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-os-memory-pools-transact-sql?view=sql-server-ver15
By default pool_id 0 is internal pool and pool_id 1 is default pool ?
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what's actually CMEMTHREAD
https://www.sqlskills.com/help/waits/cmemthread/
what's actually "TREAD-safe-memory-object" ?
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DBCC checkdb IO
I run a dbcc checkdb and use performance counter to monitor .
Page Reads/s around 22,970 .
While disk read : 1607. , it's a huge difference and why ?? Page reads doesn't mean page read from disk ?
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DBCC memory status Current commited
May i know if the current committed will also include stack memory allocation ? (which is not control by max server memory ) ?
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MEMORY BROKER
Hi All
https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-os-memory-brokers-transact-sql?view=sql-server-ver15
what's the memory broker that monitor the allocation for buffer cache ?
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SQL Licencing for Training databases
I have couple of databases that are used for training classes every now and then,, do i have to host these on a prod server with SQL licence or can they be treated as a non prod Databases ?
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Azure MI SQL Server Wait Type CXSYNC_PORT
Does anyone have an understanding to explain a CXSYNC_PORT wait type on Azure SQL Managed Instance (MI). Or where good online information
can be found?
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permissions on sa login
our applications are using sa to connect to sql serer
we want to get away from that
we are attempting to rename sa to be satemp and assign with limited permisisons
to accomplish this I am attempting to understand all dependencies on sql server objects on the sa account
how to determine what objects are owned by sa
is there a script to determine the effective permissions of a login , especially sa
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