Module: sip-router Branch: master Commit: 0e564bcd3616f9dc981bb768003545674c79c2a7 URL: http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=0e564bcd...

Author: Jan Janak jan@ryngle.com Committer: Jan Janak jan@ryngle.com Date: Wed Nov 17 18:26:32 2010 -0500

db_mysql: Fixes crash in libmysqlclient after connection reset.

Sometimes SIP-Router would crash in libmysqlclient after a connection to the server has been reset. This is caused by mysql_stmt_prepare which will reset the connection data structure if a connection has been reset. Subsequent calls to other mysql functions (mysql_stmt_execute) crash unless the connection has been re-connected. This is documented as mysql bug #33384.

A workaround is to reset and reconnect the connection explicitly immediately after mysql_stmt_prepare has failed with CR_SERVER_GONE_ERROR. This change implements exactly that.

First of all, this patch fixes a minor bug in updating the variable that keeps track of number of connection resets for each database connection and pre-pared statement. The variable needs to be incremented each time a connection is closed. Previously it was incremented only if a connection was successfully reconnected. If the reconnect attempt failed than the variable was not incremented. The function that uploads commands to the server relies on the variable to detect connection resets and may not have worked properly under some circumstances (if a connection fails to reconnect).

Function upload_cmd has been modified to close the connection explicitly if mysql_stmt_prepare fails with CR_SERVER_GONE_ERROR. This ensures that subsequent calls to mysql_stmt_exec are forced to reconnect and re-upload commands to the server. This is needed to prevent the library from crashing.

exec_cmd_safe now checks if a connection has been disconnected and if so it tries to reconnect it before executing a prepared statement. This is used to recover from failing mysql_stmt_prepare.

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modules/db_mysql/my_cmd.c | 258 +++++++++++++++++++++++++-------------------- modules/db_mysql/my_con.c | 18 ++-- modules/db_mysql/my_con.h | 10 +- 3 files changed, 158 insertions(+), 128 deletions(-)

Diff: http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commitdiff;h=0e56...