On Tue, 2008-02-26 at 12:29 +0100, Martijn van Oosterhout wrote: > > When we're running a COPY over a high latency link then network time is > > going to become dominant, so potentially, running COPY asynchronously > > might help performance for loads or initial Slony configuration. This is > > potentially more important on Slony where we do both a PQgetCopyData() > > and PQputCopyData() in a tight loop. > > When you check the packets being sent, are you showing only one record > being sent per packet? If so, there's your problem.
I've not inspected the packet flow. It seemed easier to ask. > > I also note that PQgetCopyData always returns just one row. Is there an > > underlying buffering between the protocol (which always sends one > > message per row) and libpq (which is one call per row)? It seems > > possible for us to request a number of rows from the server up to a > > preferred total transfer size. > > AIUI the server merely streams the rows to you, the client doesn't get > to say how many :) Right, but presumably we generate a new message per PQgetCopyData() request? So my presumption is we need to wait for that to be generated each time? -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
