London BI/SQL Server user groups.

If you are BI based and want to meetup with other in London, whether technical or business based here as some contacts.

https://sqlserverfaq.com/ – General sql server (covers lots of usergroups)

http://sqllondon.pass.org/ – London SQL Pass Chapter for SQL Server but BI people do attend as well.

https://www.meetup.com/London-PUG/ London Power BI Users Group – they meet at Skills Matter, 10 South Place near Moorgate tube, big group, lots of people attend – 50+,

https://www.meetup.com/London-Business-Analytics-Group/ – London Business Analytics Group – Very power user/Business based, less technical


SSMS Running remotely

To run SSMS remotely:

runas /netonly /user:domain\username “C:\Program Files (x86)\Microsoft SQL Server\130\Tools\Binn\ManagementStudio\Ssms.exe”

E.g.

runas /netonly /user:WIN-P9OQ9GF24HV\justdave “C:\Program Files (x86)\Microsoft SQL Server\130\Tools\Binn\ManagementStudio\Ssms.exe”


SQL1227N during replaying db2look -m output

 

http://www-01.ibm.com/support/docview.wss?uid=swg21991415

db2look -m -r

The “-r” option is used to generate db2look output without runstats command output. However, current db2look code cannot reset SYSSTAT.COLUMNS and SYSSTAT.INDEXES when -r is applied. As a result, SQL1227N sometimes occur when applying the mimic when COLCARD etc, and CARD for the table is inconsistent. In db2look up to version in V10.5 please use db2look -m without -r option or insert resetting SYSSTAT.COLUMNS and SYSSTAT.INDEXES manually in db2look output with “-m” and “-r”. This limitation will be changed in releases later than V10.5. In most cases it should not cause SQL1227N error, but still the error can occur when the statistics on the source system is inconsistent. Here are examples:
Why COLCARD is sometimes bigger than CARD after RUNSTATS?
http://www.ibm.com/support/docview.wss?uid=swg21985376

Runstats may update unexpected HIGH2KEY and LOW2KEY statistic values which may cause SQL1227N
http://www.ibm.com/support/docview.wss?uid=swg21979066

As documented in above technotes, you can bypass the error by setting following undocumented registry variable even if the statistics are inconsistent:

db2set DB2_STATISTICS=USCC:0
recycle the instance

This registry variable can be used from 9.7FP9/10.1FP4/10.5.

 


.NET Runtime Optimization Service

To run .NET Runtime Optimization Service:

Wondering why mscorsvw.exe has high CPU usage? You can speed it up.

c:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe executeQueuedItems
schTasks /run /Tn “\Microsoft\Windows\.NET Framework\.NET Framework NGEN v4.0.30319 64”


Using vim as a man pager

https://zameermanji.com/blog/2012/12/30/using-vim-as-manpager/

export MANPAGER=”col -b | vim -c ‘set ft=man ts=8 nomod nolist nonu’ -c ‘nnoremap i <nop>’ -”

export MANPAGER=”col -b | vim -c ‘set ft=man ts=8 nomod nolist nonu noma’ -”

For gnu man:

export MANPAGER=”/bin/sh -c \”col -b | vim -c ‘set ft=man ts=8 nomod nolist nonu noma’ -\””

 


Linux kernel networking – monitoring and tuning

http://blog.packagecloud.io/eng/2016/06/22/monitoring-tuning-linux-networking-stack-receiving-data/

Monitoring and Tuning the Linux Networking Stack: Receiving Data


Oracle APPROX_COUNT_DISTINCT Function

Some notes on the Oracle APPROX_COUNT_DISTINCT Function

The APPROX_COUNT_DISTINCT Function – A Test Case

Testing

http://externaltable.blogspot.co.uk/2014/08/scaling-up-cardinality-estimates-in.html

Scaling up Cardinality Estimates in 12.1.0.2

http://afatkulin.blogspot.co.uk/2013/11/hyperloglog-in-oracle.html

HyperLogLog in Oracle

Sketch of the Day: HyperLogLog — Cornerstone of a Big Data Infrastructure

HyperLogLog — Cornerstone of a Big Data Infrastructure