我在nodejs中创建了一个函数,该函数返回对象 QueryName 和查询
{"QueryName":"a","Query":"SELECT something from bar"}
{"QueryName":"b","Query":"SELECT something from bar"}
{"QueryName":"c","Query":"SELECT something from bar"}
{"QueryName":"d","Query":"SELECT something from bar"}
另外,我创建了另一个函数来获取查询结果。
代码到目前为止
executeQuery(connection, query, config.dbtype, response, function (error, data) {
});
function executeQuery(connection, query, dbtype, response, callback) {
DB_OPERATIONS.executeOperations(connection, APP_CONSTANT.findall, query, dbtype, null, null, "", function (error, data) {
callback(error, data);
});
};
FIND_ALL.findAllRecords(connection, query, dbtype, function(error, result) {
callback(error, result);
});
执行每个查询的时间为5秒,总时间为20秒。
如何在nodejs中并行执行每个查询?然后,而不是20秒,最多需要5秒钟来获取所有查询数据。
答案 0 :(得分:1)
正如@zabusa在评论中指出的那样,你可以使用基于承诺的功能。
以下是一些例子
var queries = [{"QueryName":"a","Query":"SELECT something from bar"}
{"QueryName":"b","Query":"SELECT something from bar"}
{"QueryName":"c","Query":"SELECT something from bar"}
{"QueryName":"d","Query":"SELECT something from bar"}]
//Promisified executeQuery
function executeQueryAsync(connection, query, dbtype, response) {
return new Promise(function(resolve, reject){
DB_OPERATIONS.executeOperations(connection, APP_CONSTANT.findall, query.Query, dbtype, null, null, "", function (error, data) {
var result = {
QueryName: query.QueryName
}
if(error){
reject(error);
return;
}
result.data = data;
resolve(result);
});
})
};
// Promise with callback
function executeMultipleQueries(callback){
var promises = [];
queries.forEach(function(query){
promises.push(executeQueryAsync(connection, query, config.dbtype, response))
})
Promise.all(promises).then(callback)
}
executeMultipleQueries(function(results){
// results[0].QueryName is a
// results[1].QueryName is b
// results[2].QueryName is c
//actually there is no need to create a result object in the promise,
//if we only revolved the data the result array will have them in the order with pushed them in the promises array
})
//Full Promise
function executeMultipleQueriesPromise(){
var promises = [];
queries.forEach(function(query){
promises.push(executeQueryAsync(connection, query, config.dbtype, response))
})
return Promise.all(promises)
}
executeMultipleQueriesPromise().then(function(results){
// results[0].QueryName is a
// results[1].QueryName is b
// results[2].QueryName is c
//actually there is no need to create a result object in the promise,
//if we only revolved the data the result array will have them in the order with pushed them in the promises array
})
答案 1 :(得分:0)
您可以使用Cluster更多进程。您可以在此线程Why is Node.js single threaded?中查看有关节点中多线程的更多信息。希望对你有所帮助。