我在NodeJS和HapiJS之上构建了一个api。
该应用程序在启动时加载大量数据，然后将其保存在内存中。我有这个应用程序运行在一个有16 GB RAM的服务器上，所以在内存中保持4 GB RAM应该是可能的。
然而，每次应用程序启动时，此错误都会在日志中出现5次：
{ Error: connect ETIMEDOUT
at Connection._handleConnectTimeout (/home/ec2-user/daemons/liar_lies/node_modules/mysql/lib/Connection.js:425:13)
at Socket.g (events.js:291:16)
at emitNone (events.js:86:13)
at Socket.emit (events.js:185:7)
at Socket._onTimeout (net.js:339:8)
at ontimeout (timers.js:365:14)
at tryOnTimeout (timers.js:237:5)
at Timer.listOnTimeout (timers.js:207:5)
--------------------
at Protocol._enqueue (/home/ec2-user/daemons/liar_lies/node_modules/mysql/lib/protocol/Protocol.js:141:48)
at Protocol.handshake (/home/ec2-user/daemons/liar_lies/node_modules/mysql/lib/protocol/Protocol.js:52:41)
at Connection.connect (/home/ec2-user/daemons/liar_lies/node_modules/mysql/lib/Connection.js:136:18)
at /home/ec2-user/daemons/liar_lies/node_modules/knex/lib/dialects/mysql/index.js:106:18
at Promise._execute (/home/ec2-user/daemons/liar_lies/node_modules/bluebird/js/release/debuggability.js:300:9)
at Promise._resolveFromExecutor (/home/ec2-user/daemons/liar_lies/node_modules/bluebird/js/release/promise.js:481:18)
at new Promise (/home/ec2-user/daemons/liar_lies/node_modules/bluebird/js/release/promise.js:77:14)
at Client_MySQL.acquireRawConnection (/home/ec2-user/daemons/liar_lies/node_modules/knex/lib/dialects/mysql/index.js:104:12)
at Object.create (/home/ec2-user/daemons/liar_lies/node_modules/knex/lib/client.js:231:16)
at Pool._createResource (/home/ec2-user/daemons/liar_lies/node_modules/generic-pool/lib/generic-pool.js:326:17)
at Pool.dispense [as _dispense] (/home/ec2-user/daemons/liar_lies/node_modules/generic-pool/lib/generic-pool.js:314:12)
at Pool.acquire (/home/ec2-user/daemons/liar_lies/node_modules/generic-pool/lib/generic-pool.js:392:8)
at /home/ec2-user/daemons/liar_lies/node_modules/knex/lib/client.js:281:19
at Promise._execute (/home/ec2-user/daemons/liar_lies/node_modules/bluebird/js/release/debuggability.js:300:9)
at Promise._resolveFromExecutor (/home/ec2-user/daemons/liar_lies/node_modules/bluebird/js/release/promise.js:481:18)
at new Promise (/home/ec2-user/daemons/liar_lies/node_modules/bluebird/js/release/promise.js:77:14)
errorno: 'ETIMEDOUT',
code: 'ETIMEDOUT',
syscall: 'connect',
fatal: true }
这是唯一的错误，每当应用程序启动时就会发生5次。
然而，该应用程序似乎确实获得了我期望它获得的大部分数据，所以无论什么查询抛出这个错误，它都一定相当模糊。
我该如何判断哪个查询会引发此错误？
stacktrace似乎没有提到我的代码中导致这种情况的那一行。(我觉得很沮丧。)
这些是我正在使用的模块：
"boom": "3.1.2",
"code": "2.1.0",
"fs": "0.0.2",
"glob": "6.0.4",
"glue": "3.1.0",
"good-console": "5.3.0",
"good-file": "5.1.2",
"hapi": "16.0.2",
"html-entities": "1.2.0",
"joi": "7.2.2",
"knex": "0.12.6",
"knex-logger": "0.1.0",
"multiline": "1.0.2",
"mysql": "2.12.0",
"path": "0.12.7",
"plugo": "0.3.1"
据我所知，只有两个函数在启动时调用数据库。这就是其中之一：
function build_maps_which_index_database_data(query, which_type_of_data_in_which_database_table) {
DB.knex.raw(query).then(
function(result) {
var count_of_database_results = result[0].length;
build_list_of_allowed_fields(result[0][0]);
for(var how_many_records_processed_so_far = 0; how_many_records_processed_so_far < count_of_database_results; how_many_records_processed_so_far++) {
var document = result[0][how_many_records_processed_so_far];
var profile_id = document['profile_id'];
document['which_type_of_data_in_which_database_table'] = which_type_of_data_in_which_database_table;
document['item_id'] = uuidV4();
build_map_of_uuid_ids_to_documents(document);
Object.keys(document).forEach(function(name_of_field_in_database) {
// avoiding name_of_field_in_database = profile_id
if (name_of_field_in_database != 'profile_id') {
var string_from_database = document[name_of_field_in_database];
build_map_of_santized_words_to_uuid_ids(name_of_field_in_database, string_from_database, document['item_id']);
}
});
}
})
.catch(function(e) {
console.log('Error: calling code was get_map_of_santized_words_to_uuid_ids');
console.log('query was: ' + query);
console.error(e);
});
}
这些函数中的每一个都附带了一个"catch"子句，所以我认为如果这是错误的原因，那么我会在日志中看到。
问题中的错误不是由问题中包含的代码引起的。
要了解发送这些错误时发生了什么，请尝试使用环境变量DEBUG=knex:*运行应用程序。这将向您显示连接池中发生了什么，以及向DB发送了哪些查询。
export DEBUG=knex:*
cd ~/yourapp
node server.js
或者只是
cd ~/yourapp
DEBUG=knex:* node server.js
还要尝试从应用程序中删除代码，直到应用程序中的代码量最小，这仍然会产生这些错误。在那之后，应该很容易找到问题的根本原因。
您还可以做的一件事是将调试信息添加到
knex.on('query-error', function (err, obj) { ... });
事件，并检查是否捕捉到这些错误。