<div class="Section1"><p class="MsoNormal"><font face="Arial" size="2"><span style="font-size:10.0pt;
font-family:Arial">SELECT 1 FROM test.dbo.a_003 </span></font><p class="MsoNormal"><font face="Times New Roman"
size="3"><spanstyle="font-size:
12.0pt"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span style="font-size:10.0pt;
font-family:Arial">gets about 60,000 records per second</span></font><p class="MsoNormal"><font face="Times New Roman"
size="3"><spanstyle="font-size:
12.0pt"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span style="font-size:10.0pt;
font-family:Arial">SELECT '1' FROM test.dbo.a_003 </span></font><p class="MsoNormal"><font face="Times New Roman"
size="3"><spanstyle="font-size:
12.0pt"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span style="font-size:10.0pt;
font-family:Arial">gets about 600 records per second.</span></font><p class="MsoNormal"><font face="Times New Roman"
size="3"><spanstyle="font-size:
12.0pt"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span style="font-size:10.0pt;
font-family:Arial">The cause is that postgres describes the return column as "unknown" length 65534 in the 2nd
case.</span></font><pclass="MsoNormal"><font face="Arial" size="2"><span style="font-size:10.0pt;
font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span style="font-size:10.0pt;
font-family:Arial">Since the value is a constant, it seems rather odd to make the length 65534 characters. Why not
makeit char(1) or some other appropriate and less costly data type? After all, it isn’t going to grow during the
query.</span></font><pclass="MsoNormal"><font face="Arial" size="2"><span style="font-size:10.0pt;
font-family:Arial"> </span></font></div>
