From cf283895369412c1bfd7fdcda981f47a3c1bd4d0 Mon Sep 17 00:00:00 2001
From: Lloyd Hilaiel <lloyd@hilaiel.com>
Date: Tue, 22 May 2012 17:53:05 -0600
Subject: [PATCH] db.ping() must use the same application level query timing
and reconnection logic as other query types - issue #1608
---
lib/db/mysql_wrapper.js | 63 ++++++++++++++++++++++++++---------------
1 file changed, 40 insertions(+), 23 deletions(-)
diff --git a/lib/db/mysql_wrapper.js b/lib/db/mysql_wrapper.js
index 45edfd7de..931ff97fb 100644
--- a/lib/db/mysql_wrapper.js
+++ b/lib/db/mysql_wrapper.js
@@ -39,14 +39,15 @@ exports.createClient = function(options) {
logger.warn("database connection down: " + e.toString());
});
},
- ping: function(cb) {
- if (stalled) {
- process.nextTick(function() {
- cb("database is intentionally stalled");
- });
- } else {
- this.realClient.ping(cb);
- }
+ ping: function(client_cb) {
+ // ping queries are added to the front of the pending work queue. they are
+ // a priority, as they are used by load balancers that want to know the health
+ // of the system.
+ queryQueue.unshift({
+ ping: true,
+ cb: client_cb
+ });
+ this._runNextQuery();
},
_runNextQuery: function() {
var self = this;
@@ -93,25 +94,41 @@ exports.createClient = function(options) {
}
}, config.get('database.max_query_time_ms'));
- this.realClient.query(work.query, work.args, function(err, r) {
- // if we want to simulate a "stalled" mysql connection, we simply
- // ignore the results from a query.
- if (stalled) return;
+ if (work.ping) {
+ this.realClient.ping(function(err) {
+ if (stalled) {
+ return invokeCallback(work.cb, "database is intentionally stalled");
+ }
- clearTimeout(slowQueryTimer);
- slowQueryTimer = null;
- consecutiveFailures = 0;
+ clearTimeout(slowQueryTimer);
+ slowQueryTimer = null;
+ consecutiveFailures = 0;
- // report query time for all queries via statsd
- var reqTime = new Date - work.startTime;
- statsd.timing('query_time', reqTime);
+ invokeCallback(work.cb, err);
- // report failed queries via statsd
- if (err) statsd.increment('failed_query');
+ self._runNextQuery();
+ });
+ } else {
+ this.realClient.query(work.query, work.args, function(err, r) {
+ // if we want to simulate a "stalled" mysql connection, we simply
+ // ignore the results from a query.
+ if (stalled) return;
- invokeCallback(work.cb, err, r);
- self._runNextQuery();
- });
+ clearTimeout(slowQueryTimer);
+ slowQueryTimer = null;
+ consecutiveFailures = 0;
+
+ // report query time for all queries via statsd
+ var reqTime = new Date - work.startTime;
+ statsd.timing('query_time', reqTime);
+
+ // report failed queries via statsd
+ if (err) statsd.increment('failed_query');
+
+ invokeCallback(work.cb, err, r);
+ self._runNextQuery();
+ });
+ }
},
query: function() {
var client_cb;
--
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