Created
November 20, 2015 16:03
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cassandra stream out of memory example
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| #!/usr/bin/env node | |
| 'use strict' | |
| const config = require('config') | |
| const cassandra = require('@our/cassandra-connection-wrapper') | |
| const stream = require('stream') | |
| let rowcount = 0 | |
| setInterval(() => console.log(rowcount, process.memoryUsage()), 1000) | |
| cassandra(config.get('cassandra')) | |
| .then(client => { | |
| const writer = new stream.Writable({ | |
| decodeStrings: false, | |
| objectMode: true, | |
| write: (chunk, encoding, next) => { | |
| ++rowcount | |
| // this works: | |
| // setImmediate(next) | |
| // this leads to OOM: | |
| setTimeout(next, 0) | |
| } | |
| }) | |
| return client.stream('SELECT small_buffer from large.table', [], { autoPage: true }) | |
| .pipe(writer) | |
| }) |
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