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Distribution key in Netezza

When you create a table in Netezza database, selecting column/s being a member of distribution key is one of the critical decision for good performance of the queries that will run against the table.

Below are some of the key points to remember when we select distribution key:

  • Maximum of four columns can be a member of distribution key
  • We can have only one distribution key per table (Which is quite obvious)
  • We cannot modify column (by issuing alter table command) which is a member of distribution key
  • We create a table with random distribution then Netezza will store data based on round robin algorithm
  • When we create a table, if no column is selected as distribution key then Netezza will randomly distribute on any column of the table and not always the first column (Most of the cases it first column but in theory it can be any column)
  • When we create a table by issuing “select * from table …….” then the newly created table will inherit the distribution key of source table.
  • Always try to avoid using different distribution key when creating a table using “select * from table …….” as this can result in transfer of data across SPU’s because of change in distribution

Find version number of all executables – Netezza server

To check the version number, revision number of all the executables in Netezza host use command ‘nzcontents’.

/export/home/nz-> nzcontents

Program Revision Stamp Build Stamp CheckSum
adm Directory
libnzodbc_nzload.s o 7.0.2-0.F-1.P-5.Bld-31017 hs02nw932ef8cec9866712d0a10c18fc
nzbackup 7.0.2-0.F-1.P-5.Bld-31017 2bb36c262c0320khab372f0cb8cd19d
nzcontents 2ecb83ff75c1d73e489957bbab372f0cb
nzconvert 7.0.2-0.F-1.P-5.Bld-31017 773e19e2bab372f0cbdc39b8cb435ddb
nzds 7.0.2-0.F-1.P-5.Bld-31017 6d1d791742f4ab372f0cb4c5fe50315e
nzevent 7.0.2-0.F-1.P-5.Bld-31017 217cbd7ab372f0cbassasaa0b88961fecb
nzhostbackup 15af730413c5eaf89asiajsnaad0829c611
nzhostrestore 1dec785a9adksdjo0091a76883ecfc6b0a
nzhw 7.0.2-0.F-1.P-5.Bld-31017 9iqnkssak9d6f0e89a74eec04cce8ead8d
nzload 7.0.2-0.F-1.P-5.Bld-31017 adi0skasjjk73ddfafb97bd50b14abad59a
nzpassword 7.0.2-0.F-1.P-5.Bld-31017 6b814d784aed0as0ansd35734e3281451
nzreclaim 79ea54ee552603f6de810asdjka9d2kjsd
nzrestore 7.0.2-0.F-1.P-5.Bld-31017 1c530eee20398aisid0wbw9w94df32a00
nzrev 7.0.2-0.F-1.P-5.Bld-31017 4ed833fb2f1d29a2981b1acc9u9dj99dac
nzsession 7.0.2-0.F-1.P-5.Bld-31017 ba2dd11f0e05ad9jdda551c45bb3cd04f
nzspupart 7.0.2-0.F-1.P-5.Bld-31017 oaois0wdihdcdd03e1f28d04c8c023812
nzsql 7.0.2-0.F-1.P-5.Bld-31017 a7598e0c18dd7b8969u39fu9a91fe1535
nzstart d8ef1254f168fd189bf8fhafhiaff816062
nzstate 7.0.2-0.F-1.P-5.Bld-31017 9b00ecahf9fa9h99af55489605a593a34
nzstats 7.0.2-0.F-1.P-5.Bld-31017 a5012dd9ed4c508e11a03b5aa9u9asf
nzstop 0a4fcf15ffcad8d74badsbidas99dc27
nzsystem 7.0.2-0.F-1.P-5.Bld-31017 d284b8ay8ha7e9

How to read revision stamp?
Like for above exampel it is 7.0.2-0.F-1.P-5.Bld-31017 for nz system.

7 -> Manjor release number
0 -> Minor release number
2 -> Service pack number / sub-minor
-0 -> Variant number. can be ignored
.F -> Release stage as production. D means developement, A means alpha and B means beta release
P-5 -> Fix release patch level. All patches are cumulative
Bld-31017 -> Production build number