NAMEDATALEN revisited

Using current CVS (yesterday) I've rerun the benchmarks to see the
effects of various NAMEDATALEN settings.

3 times per setting.

First time is pgbench inserts (-s 5)
Second time is pgbench run (-t 3000 -s 5)

Third time is the postmaster during both of the above.

I'll run it again tonight on a computer with faster disk I/O to see if
that helps descrease the sys times.

-----
NAMEDATALEN: 32

89.34 real 1.85 user 0.13 sys
146.87 real 1.51 user 3.91 sys

246.63 real 66.11 user 19.21 sys

NAMEDATALEN: 64

93.10 real 1.82 user 0.16 sys
147.30 real 1.45 user 3.90 sys

249.28 real 66.01 user 18.82 sys

NAMEDATALEN: 128

99.13 real 1.80 user 0.51 sys
169.47 real 1.87 user 4.54 sys

279.16 real 67.93 user 29.72 sys

NAMEDATALEN: 256

106.60 real 1.81 user 0.43 sys
166.61 real 1.69 user 4.25 sys

283.76 real 66.88 user 26.59 sys