Tom, you are right: it is just more complicated.
In fact, I did not pretend to demonstrate that it was easier or faster
using one file per tape.
As you can remember, I just did not understand why you said it was
*impossible* to recycle space in that case.
So, the conclusion is: you can do rec
Il 21/06/2010 04:25, Tom Lane ha scritto:
No. You could do that if the rate at which you need to write data to
the file is<= the rate at which you extract it. But for what we
are doing, namely merging runs from several tapes into one output run,
it's pretty much guaranteed that you need new spa
logical tapesets?
In other words, why Tom affirmed it was impossible to recycle space
implementing one tape per file?
Il 20/06/2010 23:20, Robert Haas ha scritto:
On Sat, Jun 19, 2010 at 4:57 AM, mac_man2...@hotmail.it
wrote:
Tom, Robert,
thank you.
Now it is clearer how space on tapes
46 PM, mac_man2...@hotmail.it
wrote:
Which is the difference between having more than one tape into a file and
having one tape per file?
It makes it easier to recycle space a little at a time. Suppose
you're merging two runs of 100 blocks each. You read in a block from
each run and wri
Ok, so let's try asking the question in another way.
Which is the difference between having more than one tape into a file
and having one tape per file?
I mean, we are peaking runs belonging to different tapes and merge those
runs.
Moreover, why space is reduced taking in account that we can
Il 18/06/2010 21:00, Robert Haas ha scritto:
On Fri, Jun 18
Did you read the rest of the comment? It explains how the code avoids this...
Robert, thanks for your reply.
I read the rest of the document, but please take in account that my
question wasn't about "avoiding".
My question is "
Hi to all.
Please take a look at the initial comment contained into the logtape.c file:
http://doxygen.postgresql.org/logtape_8c-source.html
Almost at the beginning of that file, it is affirmed that implementing
tapes on disk (quote: /by creating a separate file for each "tape"/)
will require
