Ühel kenal päeval, K, 2006-08-09 kell 10:57, kirjutas Tom Lane: > Hannu Krosing <[EMAIL PROTECTED]> writes: > > Ühel kenal päeval, K, 2006-08-09 kell 12:56, kirjutas Simon Riggs: > >> Methinks it should be the Write pointer all of the time, since I can't > >> think of a valid reason for wanting to know where the Insert pointer is > >> *before* we've written to the xlog file. Having it be the Insert pointer > >> could lead to some errors. > > > What is the difference ? > > Insert points to the next byte to be written within the internal WAL > buffers. The byte(s) preceding it haven't necessarily gotten out of > those buffers yet. Write points to the end of what we've actually > written to the kernel,
I assume that it also points to the byte after what is written to kernel, or is it tha last byte written ? > and there's also a Flush pointer that points > to the end of what we believe is down on disk. > > Simon's point is that if you're going to use pg_current_xlog_location() > to control partial shipping of xlog files, you probably want to know > about the Write location, because that indicates the limit of what > is visible to an external process. Yes, that is what I need > regards, tom lane -- ---------------- Hannu Krosing Database Architect Skype Technologies OÜ Akadeemia tee 21 F, Tallinn, 12618, Estonia Skype me: callto:hkrosing Get Skype for free: http://www.skype.com ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
