On Jan 28, 2008, at 6:14 PM, Simon Riggs wrote:
On Sun, 2008-01-27 at 21:04 -0500, Tom Lane wrote:
[ redirecting thread to -hackers ]
Neil Conway <[EMAIL PROTECTED]> writes:
On Sun, 2008-01-27 at 21:54 +0000, Gregory Stark wrote:
I liked the "synchronized_sequential_scans" idea myself.
I think that's a bit too long. How about "synchronized_scans", or
"synchronized_seqscans"?
We have enable_seqscan already, so that last choice seems to fit in.
If we're going to have a GUC, we may as well make it as useful as
possible.
Currently we set synch scan on when the table is larger than 25% of
shared_buffers. So increasing shared_buffers can actually turn this
feature off.
Rather than having a boolean GUC, we should have a number and make the
parameter "synchronised_scan_threshold". This would then be the
size of
a table above which we would perform synch scans. If its set to -1,
then
this would be the same as "off" in all cases. The default value
would be
25% of shared_buffers. (Think we can only do that at initdb time
currently).
If we do that, its clearly different from the enable_* parameters, so
the name is easier to decide ;-)
+1
This is in fact a lot more flexible and transparent.
It gives us a lot more control over the process and it is easy to
explain / understand.
best regards,
hans
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