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very large Databases in your future Eric Peterson
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VLDB how large? impact? why? easy fixes other fixes maintenance
operations
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how large? terabyte + depends on hardware examples
2.2 TB (2,222 GB) db EMC VNX 5500 SAN 2 - 4 gb HBA 10 gb nic
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impact? Everything takes longer ! Example db raw disk I/O SQLIO
raw network 2.2 TB = 2,222 GB sqliosim | iometer I/O 397 MB/sec = 23 GB/min 10gb/sec = 1.25 GB/sec = 75 GB/min
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impact?
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impact? backup / restore copies & initial sync re-index
19 GB/min or 2,222 GB in 108 min 75 GB/min or 2,222 GB in 30 min 11 GB/min or 2,222 GB in 300 min
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I/O data transfers backup 19 GB/min hh:mm GB 00:05 100 00:49 1000
01:48 2222 08:06 10,000
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I/O data transfers copy 75 GB/min hh:mm GB 00:01 100 00:13 1,000 00:30
2,222 02:13 10,000
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I/O data transfers reindex 11 GB/min hh:mm GB 00:14 100 02:15 1,000
05:00 2,222 2230 10,000
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impact? maintenance window query optimizer; 200 step histogram
test environment large logs TempDB temp tables, sorts, joins, online indexing, snapshot isolation
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why? queries & rollbacks network copies backups synchronization
one table 266m rows 222GB data, 285GB index 20 sec table scan graphic of disk, memory & network
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Easy fixes compress data Enterprise Edition less I/O, more CPU
per table / index sp_estimate_data_compression_savings no LOB compression estimator sql slavasql.blogspot.co.uk/2014/08/sql-server-data-compression-hidden-gem.html
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“easy” fixes archive / purge data old / unnecessary data
multiple TempDB files upgrade system / hardware add RAM faster disks
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Other fixes partitioning Enterprise Edition per table
needs useful primary key sliding window automation reference to codeplex.com partitioning
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other fixes
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other fixes multiple data files concurrent reads/writes
requires file groups maintenance window to move data columnstore (in-memory) indexes be aware of restrictions
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other fixes multiple data files
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Maintenance online index rebuild Enterprise Edition duplicate space
no XML, spatial, columnstore single partition reindex Paul Randall DBCC with VLDB article
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Maintenance DBCC run on copy CheckAlloc, CheckCatalog, CheckTable
Paul Randall DBCC VLDB article filegroups manually grow equal size files
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Operations monitoring sp_whoisactive sys.dm_exec_procecure_stats
history output from whoisactive and sys.dm…
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Operations monitoring (with history) sp_whoisactive
sys.dm_exec_procedure_stats history output from whoisactive and sys.dm…
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operations look for anomalies can change query plan
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operations query tuning scans of large tables joins to large tables
excessive reads
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operations query tuning large table scans large joins excessive reads
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Operations work in batches
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Operations snapshot isolation Change Data Capture
new data to warehouse NOLOCK ? parallelism cost threshold
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thanks! contact info Eric Peterson
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Thank you to all of our Sponsors!
Diamond Sponsors Platinum Sponsors Gold Sponsors Marquee Sponsors 9/19/2015 SQLSaturday #441 – Denver 2015
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Thank you to all of our Sponsors!
Silver Sponsors SWAG Sponsors 9/19/2514 SQLSaturday #441 – Denver 2015
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