Question

我已经下载了Geonames数据库转储，并且试图将所有内容放入postgresql表中，但是无论尝试如何，我都会遇到多个错误。

我所做的最后修改：

Error: Connection terminated by user
    at Client.end (/media/DarkHawk/srv/Databases/PremadeDB/Geonames/node_modules/pg/lib/client.js:402:36)
    at Pool._remove (/media/DarkHawk/srv/Databases/PremadeDB/Geonames/node_modules/pg-pool/index.js:135:12)
    at Timeout.setTimeout (/media/DarkHawk/srv/Databases/PremadeDB/Geonames/node_modules/pg-pool/index.js:38:12)
    at ontimeout (timers.js:498:11)
    at tryOnTimeout (timers.js:323:5)
    at Timer.listOnTimeout (timers.js:290:5)
Line added  6052 0.05135667935111022%
(node:31819) UnhandledPromiseRejectionWarning: Error: This socket is closed
    at Socket._writeGeneric (net.js:729:18)
    at Socket._write (net.js:783:8)
    at doWrite (_stream_writable.js:397:12)
    at writeOrBuffer (_stream_writable.js:383:5)
    at Socket.Writable.write (_stream_writable.js:290:11)
    at Socket.write (net.js:707:40)
    at Connection.end (/media/DarkHawk/srv/Databases/PremadeDB/Geonames/node_modules/pg/lib/connection.js:318:22)
    at global.Promise (/media/DarkHawk/srv/Databases/PremadeDB/Geonames/node_modules/pg/lib/client.js:410:23)
    at new Promise (<anonymous>)
    at Client.end (/media/DarkHawk/srv/Databases/PremadeDB/Geonames/node_modules/pg/lib/client.js:409:12)
(node:31819) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:31819) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:31819) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 end listeners added. Use emitter.setMaxListeners() to increase limit

我的代码是：

var pg = require("pg");
var fs = require('fs');

const pool = new pg.Pool({
  user: 'smurf',
  host: 'localhost',
  database: 'mydb',
  password: 'smurf',
  port: 5432,
})

var filename = 'allCountries.txt';

var fs = require('fs'),
  es = require('event-stream');

var lineNr = 0;
var max = 11784251; // Number of line, dirty, to get % of lines inserted

// Connect to Postgresql
pool.connect((err, client, done) => {
  if (err) throw err

  // Stream file line by line
  var s = fs.createReadStream(filename)
    .pipe(es.split())
    .pipe(es.mapSync(function(e) {

        // pause the readstream
        s.pause();

        lineNr += 1;

        // Each line need to be properly formated
        e = e.split("\t"); //TAB split

        // The following fields need formating
        e[0] = parseInt(e[0]);
        e[4] = parseFloat(e[4]);
        e[5] = parseFloat(e[5]);
        e[14] = parseInt(e[14]);

        e[15] = e[15] == '' ? 0 : e[15];

        e[16] = parseInt(e[16]);

        // Insert into db
        pool.query('INSERT INTO geonames.rawdata (geonameid, name, asciiname, alternatenames, latitude, longitude, fclass, fcode, country, cc2, admin1, admin2, admin3, admin4, population, elevation, gtopo30, timezone, moddate) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16, $17, $18, $19);', e, function(err, result) {
          if (err) {
            console.log(err);

          }
          done(); // Release this connection to the pool
          console.log("Line added ", lineNr, (lineNr / max * 100) + "%") // Monitor progress
          s.resume(); // Go to next line

        });

      })
      .on('error', function(err) {
        console.log('Error while reading file.', err);
      })
      .on('end', function() {
        console.log('Read entire file.')
      })
    );
}) // END pool.connect

我尝试使用ReadFile，ReadFileSync，readline扩展名。移动或忽略done()函数，或只是移动它。

我通常使用php插入大量文件，所以我不知道我在这里做错了什么。

MaxListenersExceededWarning 错误对我来说毫无意义，因为似乎我关闭了所有打开的内容。我在这里做什么错了？

谢谢！

Answer 1

如注释中所述-在处理异步代码时，您需要使用stdafx.h而不是stdafx.h操作，并在插入项目后调用回调。

如果使用此选项，则不再需要对map和mapSync的调用（这由pause完成），您只需要恢复创建的最后一个流。然后是一个问题，何时应调用resume-即：在完成所有操作之后。

您的代码应如下所示：

event-stream

以上版本的代码将不会使用您正在创建的池-它会一次对一项进行操作。

如果您使用的节点是最新的（8.4+），则可以使用我自己的scramjet框架，该框架将允许使用ES6异步函数编写更简单的代码：

done

上面的代码将尝试使用该池运行32个并行插入（在每个条目上请求一个客户端-pg pool.query方法将重复使用并将客户端添加到其设置的限制中。这并不意味着一定会快32倍-由于存在一些外部限制因素，但您应该看到速度急剧提高。

如何使用Node将Geonames 1.5Gib文件正确插入Postgresql？

1 个答案: