diff options
| author | Bruce Momjian <bruce@momjian.us> | 2004-01-09 02:02:43 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2004-01-09 02:02:43 +0000 |
| commit | 0150dbdce54f24596547048d4d6617d62a2570a4 (patch) | |
| tree | b2093a0e2efb39f29ce45bc3464b25dd6b298fba /doc/src | |
| parent | acc57543debdd2de93c2c5df31702ef8ecd461b5 (diff) | |
Allow libpq to do thread-safe SIGPIPE handling. This allows it to
ignore SIGPIPE from send() in libpq, but terminate on any other SIGPIPE,
unless the user installs their own signal handler.
This is a minor fix because the only time you get SIGPIPE from libpq's
send() is when the backend dies.
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/libpq.sgml | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml index 248d8646af2..bfd66945f9c 100644 --- a/doc/src/sgml/libpq.sgml +++ b/doc/src/sgml/libpq.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.144 2003/12/13 23:59:06 neilc Exp $ +$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.145 2004/01/09 02:02:43 momjian Exp $ --> <chapter id="libpq"> @@ -3587,7 +3587,7 @@ thread-enabled applications. One restriction is that no two threads attempt to manipulate the same <structname>PGconn</> object at the same time. In particular, you cannot issue concurrent commands from different threads through the same -connection object. (If you need to run concurrent commands, start up +connection object. (If you need to run concurrent commands, use multiple connections.) </para> @@ -3612,6 +3612,25 @@ not thread-safe.<indexterm><primary>crypt</><secondary>thread safety</></> It is better to use the <literal>md5</literal> method, which is thread-safe on all platforms. </para> + +<para> +<application>libpq</application> must ignore <literal>SIGPIPE</> signals +generated internally by <function>send()</> calls to backend processes. +When <productname>PostgreSQL</> is configured without +<literal>--enable-thread-safety</>, <application>libpq</> sets +<literal>SIGPIPE</> to <literal>SIG_IGN</> before each +<function>send()</> call and restores the original signal handler after +completion. When <literal>--enable-thread-safety</> is used, +<application>libpq</> installs its own <literal>SIGPIPE</> handler +before the first database connection if no custom <literal>SIGPIPE</> +handler has been installed previously. This handler uses thread-local +storage to determine if a <literal>SIGPIPE</> signal has been generated +by an internal <function>send()</>. If an application wants to install +its own <literal>SIGPIPE</> signal handler, it should call +<function>PQinSend()</> to determine if it should ignore the +<literal>SIGPIPE</> signal. This function is available in both +thread-safe and non-thread-safe versions of <application>libpq</>. +</para> </sect1> |