minute and a half to decode a 500Kb on a fairly fast machine. I think the
culprit is sscanf.
I attach a patch that replaces the function with one used to perform the same
task in pyPgSQL (a Python interface to PostgreSQL). This code was written by
Billy Allie, author of pyPgSQL. I've changed a few variable names to match
those in the original code and removed a bit of Pythonness.
Billy has kindly looked at the code and points out that it is slightly
stricter than the original implementation and if it encounters an invalid
bytea such as '\12C' it drops the unescape '\' and outputs '12C'.
The code is licensed by the author under a BSD license.
I've performed limited testing of the function by putting JPEGs into
PostgreSQL, extracting them using them using the new function and diffing
against the original files.
The new function is significantly faster on my machine with the JPEGs being
decoded in less than a second. I attach a modified libpq example program that
I used for my testing.
Ben Lamb.
protocol 3, then falls back to 2 if postmaster rejects the startup packet
with an old-format error message. A side benefit of the rewrite is that
SSL-encrypted connections can now be made without blocking. (I think,
anyway, but do not have a good way to test.)
Win32 port is now called 'win32' rather than 'win'
add -lwsock32 on Win32
make gethostname() be only used when kerberos4 is enabled
use /port/getopt.c
new /port/opendir.c routines
disable GUC unix_socket_group on Win32
convert some keywords.c symbols to KEYWORD_P to prevent conflict
create new FCNTL_NONBLOCK macro to turn off socket blocking
create new /include/port.h file that has /port prototypes, move
out of c.h
new /include/port/win32_include dir to hold missing include files
work around ERROR being defined in Win32 includes
handle multiple 'formats' for data I/O. Restructure CommandDest and
DestReceiver stuff one more time (it's finally starting to look a bit
clean though). Code now matches latest 3.0 protocol document as far
as message formats go --- but there is no support for binary I/O yet.
of Describe on a prepared statement. This was in the original 3.0
protocol proposal, but I took it out for reasons that seemed good at
the time. Put it back per yesterday's pghackers discussion.
for tableID/columnID in RowDescription. (The latter isn't really
implemented yet though --- the backend always sends zeroes, and libpq
just throws away the data.)
initial values and runtime changes in selected parameters. This gets
rid of the need for an initial 'select pg_client_encoding()' query in
libpq, bringing us back to one message transmitted in each direction
for a standard connection startup. To allow server version to be sent
using the same GUC mechanism that handles other parameters, invent the
concept of a never-settable GUC parameter: you can 'show server_version'
but it's not settable by any GUC input source. Create 'lc_collate' and
'lc_ctype' never-settable parameters so that people can find out these
settings without need for pg_controldata. (These side ideas were all
discussed some time ago in pgsql-hackers, but not yet implemented.)
rewritten and the protocol is changed, but most elog calls are still
elog calls. Also, we need to contemplate mechanisms for controlling
all this functionality --- eg, how much stuff should appear in the
postmaster log? And what API should libpq expose for it?
have length words. COPY OUT reimplemented per new protocol: it doesn't
need \. anymore, thank goodness. COPY BINARY to/from frontend works,
at least as far as the backend is concerned --- libpq's PQgetline API
is not up to snuff, and will have to be replaced with something that is
null-safe. libpq uses message length words for performance improvement
(no cycles wasted rescanning long messages), but not yet for error
recovery.
with variable-width fields. No more truncation of long user names.
Also, libpq can now send its environment-variable-driven SET commands
as part of the startup packet, saving round trips to server.
problems in applications that may have a large number of files open,
such that libpq's socket number exceeds the range supported by fd_set.
From Chris Brown.
