Re: Page Checksums + Double Writes - Mailing list pgsql-hackers

For what's worth here are the numbers on one of our biggest databases
(same system as I posted about separately wrt seq_scan_cost vs
random_page_cost).


0053 1001
00BA 1009
0055 1001
00B9 1020
0054 983
00BB 1010
0056 1001
00BC 1019
0069 0
00BD 1009
006A 224
00BE 1018
006B 1009
00BF 1008
006C 1008
00C0 1006
006D 1004
00C1 1014
006E 1016
00C2 1023
006F 1003
00C3 1012
0070 1011
00C4 1000
0071 1011
00C5 1002
0072 1005
00C6 982
0073 1009
00C7 996
0074 1013
00C8 973
0075 1002
00D1 987
0076 997
00D2 968
0077 1007
00D3 974
0078 1012
00D4 964
0079 994
00D5 981
007A 1013
00D6 964
007B 999
00D7 966
007C 1000
00D8 971
007D 1000
00D9 956
007E 1008
00DA 976
007F 1010
00DB 950
0080 1001
00DC 967
0081 1009
00DD 983
0082 1008
00DE 970
0083 988
00DF 965
0084 1007
00E0 984
0085 1012
00E1 1004
0086 1004
00E2 976
0087 996
00E3 941
0088 1008
00E4 960
0089 1003
00E5 948
008A 995
00E6 851
008B 1001
00E7 971
008C 1003
00E8 954
008D 982
00E9 938
008E 1000
00EA 931
008F 1008
00EB 956
0090 1009
00EC 960
0091 1013
00ED 962
0092 1006
00EE 933
0093 1012
00EF 956
0094 994
00F0 978
0095 1017
00F1 292
0096 1004
0097 1005
0098 1014
0099 1012
009A 994
0035 1003
009B 1007
0036 1004
009C 1010
0037 981
009D 1024
0038 1002
009E 1009
0039 998
009F 1011
003A 995
00A0 1015
003B 996
00A1 1018
003C 1013
00A5 1007
003D 1008
00A3 1016
003E 1007
00A4 1020
003F 989
00A7 375
0040 989
00A6 1010
0041 975
00A9 3
0042 994
00A8 0
0043 1010
00AA 1
0044 1007
00AB 1
0045 1008
00AC 0
0046 991
00AF 4
0047 1010
00AD 0
0048 997
00AE 0
0049 1002
00B0 5
004A 1004
00B1 0
004B 1012
00B2 0
004C 999
00B3 0
004D 1008
00B4 0
004E 1007
00B5 807
004F 1010
00B6 1007
0050 1004
00B7 1007
0051 1009
00B8 1006
0052 1005
0057 1008
00C9 994
0058 991
00CA 977
0059 1000
00CB 978
005A 998
00CD 944
005B 971
00CC 972
005C 1005
00CF 969
005D 1010
00CE 988
005E 1006
00D0 975
005F 1015
0060 989
0061 998
0062 1014
0063 1000
0064 991
0065 990
0066 1000
0067 947
0068 377
00A2 1011


On 23/12/11 14:23, Kevin Grittner wrote:
> Jeff Janes <jeff.janes@gmail.com> wrote:
>  
> > Could we get some major OLTP users to post their CLOG for
> > analysis?  I wouldn't think there would be much
> > security/propietary issues with CLOG data.
>  
> FWIW, I got the raw numbers to do my quick check using this Ruby
> script (put together for me by Peter Brant).  If it is of any use to
> anyone else, feel free to use it and/or post any enhanced versions
> of it.
>  
> #!/usr/bin/env ruby
> 
> Dir.glob("*") do |file_name|
>   contents = File.read(file_name)
>   total = 
>     contents.enum_for(:each_byte).enum_for(:each_slice,
> 256).inject(0) do |count, chunk|
>       if chunk.all? { |b| b == 0x55 }
>         count + 1
>       else
>         count
>       end
>     end
>   printf "%s %d\n", file_name, total
> end
>  
> -Kevin
> 
> -- 
> Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-hackers