interpreting dmv’s & practical uses
DESCRIPTION
Interpreting DMV’s & practical uses. Jannie Muller mullerjannie.wordpress.com. Making sense of – Dynamic Manage Views. And other practical DBA stuff!. Troubleshooting Timeline “Wh ere do we start ?!”. “ sys.configurations VS. sp_configure .”. sys.configurations Degree of parallelism - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/1.jpg)
Interpreting DMV’s & practical uses
Jannie Mullermullerjannie.wordpress.com
![Page 2: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/2.jpg)
wellington.sqlpass.org
![Page 3: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/3.jpg)
Making sense of – Dynamic Manage ViewsAnd other practical DBA stuff!
![Page 4: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/4.jpg)
Troubleshooting Timeline“Where do we start ?!”
sys.
config
uratio
ns
sys.
dm_o
s_m
emory
_cle
rks
sys.
dm_e
xec_
reques
ts
sys.
dm_d
b_index
_oper
atio
nal_s
tats
sys.
dm_o
s_buffe
r_des
crip
tors
“Simple. From left to right … right ?”
wellington.sqlpass.org
![Page 5: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/5.jpg)
“sys.configurations VS. sp_configure.”
o sys.configurations
o Degree of parallelismo Server memoryo Query memoryo Full text crawl bandwitho CPU affinityo Fillfactor
![Page 6: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/6.jpg)
“sys.configurations VS. sp_configure.”
Hard affinity.
No affinity.
![Page 7: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/7.jpg)
“sys.dm_os_sys_info and sys.dm_os_memory_Clerks”
o sys.dm_os_sys_info
o Number of CPUs(cpu count)o Hyperthreading ratioo System Memoryo Restart dateo Affinity (scheduler count)
o sys.dm_os_memory_clerks
o NUMA Nodes
![Page 8: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/8.jpg)
“sys.dm_os_buffer_descriptors”
o sys.dm_os_buffer_descriptors
o Row per item in the buffer pool.o Page types.
![Page 9: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/9.jpg)
Troubleshooting Timeline“Where do we start ?!”
sys.
config
uratio
ns
sys.
dm_o
s_m
emory
_cle
rks
sys.
dm_e
xec_
reques
ts
sys.
dm_d
b_index
_oper
atio
nal_s
tats
sys.
dm_o
s_buffe
r_des
crip
tors
“Know your system… backwards, inside out.”
sys.configurationssys.dm_os_sys_infosys.dm_os_memory_clerks
wellington.sqlpass.org
![Page 10: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/10.jpg)
Sp_who2
o sp_who2 ‘active’
o Active requestso Blockingo NUMAo Server start dateo Long running processes
o Log, mirror, jobs,brokero Gauge workload
o Checkpointso Status
o Runnable\waitingo Fulltexto System threads
![Page 11: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/11.jpg)
select 100.*sum(signal_wait_time_ms)/sum(wait_time_ms),100.*sum(wait_time_ms -signal_wait_time_ms)/sum(wait_time_ms)
from sys.dm_os_wait_stats -- resource & CPU waits.
“sys.dm_os_wait_stats and sys.dm_os_waiting_tasks”
o sys.dm_os_wait_stats
o Historicalo Overall wait typeso Filter on typeso Resource waitso Signal (CPU waits)
o sys.dm_os_waiting_tasks
o Currento Who is blockingo What is it blocking ono Activityo Bottlenecks
![Page 12: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/12.jpg)
select 100.*sum(signal_wait_time_ms)/sum(wait_time_ms),100.*sum(wait_time_ms -signal_wait_time_ms)/sum(wait_time_ms)
from sys.dm_os_wait_stats -- resource & CPU waits.
“sys.os_wait_stats and sys.dm_waiting_tasks”
o sys.dm_os_wait_stats
o Historicalo Overall wait typeso Filter on typeso Resource waitso Signal (CPU waits)
o sys.dm_os_waiting_tasks
o Currento Who is blockingo What is it blocking ono Activityo Bottlenecks
![Page 13: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/13.jpg)
“sys.dm_exec_requests and sys.dm_exec_query_stats” o sys.dm_exec_query_stats
o Historicalo Logical \ Physical reads(IO)o Total worker time (CPU)o Execution Counto Text handle.
o sys.dm_exec_requests
o Currento Who is executingo What is it blocking ono Activityo Text Handleo read \ writes \ cpuo Percentage completeo Schedulerso Wait types
![Page 14: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/14.jpg)
“sys.exec_requests and sys.dm_exec_query_stats”
o sys.dm_exec_query_stats
o Historicalo Logical \ Physical reads(IO)o Total worker time (CPU)o Execution Counto Text handle.
o sys.dm_exec_requests
o Currento Who is executingo What is it blocking ono Activityo Text Handle
![Page 15: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/15.jpg)
“sys.dm_exec_query_stats” When it works, it works well…
..that issue on a Friday afternoon just before Beer’o clock.
![Page 16: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/16.jpg)
Butterfly effect… Table details: 200mb, 600k rows.
@ 200 executions per second, it makes a difference.
![Page 17: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/17.jpg)
“sp_recompile” - The solution
![Page 18: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/18.jpg)
Troubleshooting Timeline“Where do we start ?!”
sys.
config
uratio
ns
sys.
dm_o
s_m
emory
_cle
rks
sys.
dm_e
xec_
reques
ts
sys.
dm_d
b_index
_oper
atio
nal_s
tats
sys.
dm_o
s_buffe
r_des
crip
tors
“Know your workload… and the hardware threshold”
sys.dm_os_wait_stats.sys.dm_os_waiting_taskssys.dm_exec_requestssys.dm_exec_query_stats
wellington.sqlpass.org
![Page 19: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/19.jpg)
“sys.dm_io_virtual_file_stats”
SQL VS. Excel
o Cumulativeo read \ Write waits.o Data Vs. log file.
![Page 20: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/20.jpg)
o sys.dm_db_index_usage_stats
o Historicalo Seeko Scano Lookupo Updateo Last used date
o sys.dm_db_index_operational_stats
o Waits or latcheso Range or singleton lookup
o sys.dm_db_index_physical_stats
o Fragmentationo Size
“You can use sys.dm_db_index_operational_stats to track the length of time that users must wait to read or write to a table, index, or partition, and identify the tables or indexes that are encountering significant I/O activity or
hot spots.” - BOL
“sys.dm_db_index_usage_stats , sys.dm_db_index_operational_stats , sys.dm_db_index_physical_stats”
![Page 21: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/21.jpg)
“sys.dm_db_index_usage_stats , sys.dm_db_index_operational_stats , sys.dm_db_index_physical_stats”
o sys.dm_db_index_usage_stats
o Historicalo Seeko Scano Lookupo Updateo Last used date
o sys.dm_db_index_operational_stats
o Waits or latcheso Range or singleton lookup
o sys.dm_db_index_physical_stats
o Fragmentationo Size
![Page 22: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/22.jpg)
“sys.dm_db_index_usage_stats , sys.dm_db_index_operational_stats , sys.dm_db_index_physical_stats”
o sys.dm_db_index_usage_stats
o Historicalo Seeko Scano Lookupo Updateo Last used date
o sys.dm_db_index_operational_stats
o Waits or latcheso Range or singleton lookup
o sys.dm_db_index_physical_stats
o Fragmentationo Size
![Page 23: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/23.jpg)
“sys.dm_db_index_usage_stats , sys.dm_db_index_operational_stats , sys.dm_db_index_physical_stats”
o sys.dm_db_index_usage_stats
o Historicalo Seeko Scano Lookupo Updateo Last used date
o sys.dm_db_index_operational_stats
o Waits or latcheso Range or singleton lookup
o sys.dm_db_index_physical_stats
o Fragmentationo Size
“The value for avg_fragmentation_in_percent should be as close to zero as possible for maximum performance. However, values from 0 percent through 10 percent may be
acceptable. All methods of reducing fragmentation, such as rebuilding, reorganizing, or re-creating, can be used to reduce these values. “ - BOL
![Page 24: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/24.jpg)
Troubleshooting Timeline“Where do we start ?!”
sys.
config
uratio
ns
sys.
dm_o
s_m
emory
_cle
rks
sys.
dm_e
xec_
reques
ts
sys.
dm_d
b_index
_oper
atio
nal_s
tats
sys.
dm_o
s_buffe
r_des
crip
tors
“Simple. From left to right … right ?”
Set yourself goals to spend limited time on a DMV.
Just because it’s not in SQL doesn’t mean you can’t use it.
Combine your DMV information with data from Win 2008 resource monitor. Use excel to visualize your data. Don’t forget to all the tools available to you.
Most importantly don’t forgot sp_who2.
![Page 25: Interpreting DMV’s & practical uses](https://reader035.vdocuments.net/reader035/viewer/2022062217/568150ae550346895dbec74a/html5/thumbnails/25.jpg)
Thanks! Questions?
Please complete an evaluation form for this session…and thanks again to our awesome sponsors!