Cassandra NodeJS driver & NodeJS Paris
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This document provides an overview of the NodeJS Cassandra driver. It begins with a brief introduction of Cassandra and then discusses the driver's architecture, streaming capabilities, and API. Key aspects covered include connection pooling, request pipelining, load balancing policies, automatic failover, and data type mappings. The presentation concludes with a code example and demonstration of the driver.
![Cluster!
@doanduyhai
7
Random: hash of #partition → token = hash(#p)
Hash: ]0, 2127-1]
Each node: 1/8 of ]0, 2127-1]
n1
n2
n3
n4
n5
n6
n7
n8](https://image.slidesharecdn.com/cassandranodejsdriver-141015172528-conversion-gate01/85/Cassandra-NodeJS-driver-NodeJS-Paris-7-320.jpg)
![Common Usage!
@doanduyhai
32
var cassandra = require('cassandra-driver');
var client = new cassandra.Client({contactPoints: [’192.168.0.12', ’node2'],
keyspace: ’my_keyspace'});
var query = 'SELECT email, last_name FROM users WHERE login=?';
client.execute(query, [’jdoe'], function(err, result) {
console.log('got user with email ' + result.rows[0].email);
});](https://image.slidesharecdn.com/cassandranodejsdriver-141015172528-conversion-gate01/85/Cassandra-NodeJS-driver-NodeJS-Paris-32-320.jpg)
![API!
@doanduyhai
33
Insert/Update
var query = ‘’INSERT INTO sensor_data(id,date,value) VALUES(?, ?, ?)’’;
client.query(query,
[‘mySensor’, ‘2014-10-15 12:00:00’, 34.5],
{prepare: true, consistency: cassandra.types.consistencies.one},
function(err) { //error handling });](https://image.slidesharecdn.com/cassandranodejsdriver-141015172528-conversion-gate01/85/Cassandra-NodeJS-driver-NodeJS-Paris-33-320.jpg)
![API!
@doanduyhai
34
Select
var query = ‘’SELECT * sensor_data WHERE id = ?’’;
client.query(query,
[‘mySensor’],
{prepare: true, consistency: cassandra.types.consistencies.one},
function(err, result) {
result.rows.forEach(function(row) {
console.log(‘value = ‘ + row.value);
});
});](https://image.slidesharecdn.com/cassandranodejsdriver-141015172528-conversion-gate01/85/Cassandra-NodeJS-driver-NodeJS-Paris-34-320.jpg)
![Streaming!
@doanduyhai
36
var query = ‘’SELECT * FROM sensor_data‘’;
var stream = client.stream(query, [ ], {autoPage: true});
Default fetchSize = 5000](https://image.slidesharecdn.com/cassandranodejsdriver-141015172528-conversion-gate01/85/Cassandra-NodeJS-driver-NodeJS-Paris-36-320.jpg)
Cassandra NodeJS driver & NodeJS Paris
- 1. NodeJS Cassandra driver DuyHai DOAN, Technical Advocate @doanduyhai
- 2. Shameless self-promotion! @doanduyhai 2 Duy Hai DOAN Cassandra technical advocate • talks, meetups, confs • open-source devs (Achilles, …) • Cassandra technical point of contact duy_hai.doan@datastax.com
- 3. Agenda! @doanduyhai 3 C* quick intro • Cluster, Replication, Consistency, Data Model NodeJS Driver • Architecture, Streaming, API Live DEMO!
- 4. Cassandra history! @doanduyhai 4 NoSQL database • created at Facebook • open-sourced since 2008 • current version = 2.1 • column-oriented ☞ distributed table
- 5. Cassandra in 5 points! @doanduyhai 5 • Linear scalability • Continuous availability (≈100% up-time) • Multi-data centers • Consistent performance (99% percentile) • Operational simplicity
- 6. Cassandra quick intro! Cluster Replication Consistency
- 7. Cluster! @doanduyhai 7 Random: hash of #partition → token = hash(#p) Hash: ]0, 2127-1] Each node: 1/8 of ]0, 2127-1] n1 n2 n3 n4 n5 n6 n7 n8
- 8. Linear scalability! @doanduyhai 8 n1 n2 8 nodes 10 nodes n3 n4 n5 n6 n7 n8 n1 n2 n3 n4 n5 n6 n7 n9 n8 n10
- 9. Failure tolerance! @doanduyhai 9 Replication Factor (RF) = 3 n1 n2 n3 n4 n5 n6 n7 n8 1 2 3
- 10. Coordinator node! Incoming requests (read/write) Coordinator node handles the request Every node can be coordinator àmasterless @doanduyhai n1 n2 n3 n4 n5 n6 n7 n8 1 2 3 coordinator request
- 11. Consistency! @doanduyhai 11 Tunable at runtime • ONE • QUORUM (strict majority w.r.t. RF) • ALL Apply both to read & write
- 12. Write consistency! Write ONE • write request to all replicas in // • wait for ONE ack before returning to client • other acks later, asynchronously @doanduyhai n1 n2 n3 n4 n5 n6 n7 n8 1 2 3 coordinator
- 13. Write consistency! Write QUORUM • write request to all replicas in // • wait for QUORUM acks before returning to client • other acks later, asynchronously @doanduyhai n1 n2 n3 n4 n5 n6 n7 n8 1 2 3 coordinator
- 14. Read consistency! Read ONE • read from one node among all replicas • contact the least-loaded node (stats) @doanduyhai n1 n2 n3 n4 n5 n6 n7 n8 1 2 3 coordinator
- 15. Read consistency! Read QUORUM • read from one least-loaded node • AND request digest from other replicas to reach QUORUM • return most up-to-date data to client • repair if digest mismatch n1 @doanduyhai n2 n3 n4 n5 n6 n7 n8 1 2 3 coordinator
- 17. CRUD Operations! @doanduyhai 17 INSERT INTO users(login, name, age) VALUES(‘jdoe’, ‘John DOE’, 33); UPDATE users SET age = 34 WHERE login = jdoe; DELETE age FROM users WHERE login = jdoe; SELECT age FROM users WHERE login = jdoe;
- 18. DDL! @doanduyhai 18 CREATE TABLE users ( login text, name text, age int, … PRIMARY KEY(login)); partition key (#partition)
- 19. Cassandra NodeJS Driver! Architecture! Streaming! API!
- 20. Connection pooling! @doanduyhai 20 n3 n2 n4 Client Pool1 Pool2 Pool3 CallBack1 CallBack2 CallBack3
- 21. Request Pipelining! @doanduyhai 21 Client Cassandra
- 22. Request Pipelining! @doanduyhai 22 Client Cassandra StreamID StreamID
- 23. Nodes Discovery! @doanduyhai 23 n2 n3 n4 n5 n6 n7 n8 Control Connection n1 Client
- 24. Round Robin Load Balancing! @doanduyhai 24 n2 n3 n4 n5 n6 n7 n8 n1 Client 1 2 3 4
- 25. DC Aware Load Balancing! @doanduyhai 25 Client1 DC1 ⤫ Client2 DC2
- 26. DC Aware Load Balancing! @doanduyhai 26 ⤫ Client1 DC1 Client2 DC2
- 27. Token Aware Load Balancing! @doanduyhai 27 n2 n3 n4 n5 n6 n7 n8 1 n1 Client 2 3 ⤫
- 28. Combining Load Balancing Policies! Token Aware Round Robin DC Aware Round Robin @doanduyhai 28 extends Load Balancing Policy wraps Default config
- 29. Automatic Failover! @doanduyhai 29 n3 n2 n4 Client Pool1 Pool2 Pool3 Request ⤫
- 30. Other policies! @doanduyhai 30 Retry policy • write/read timeout • node unavailable Reconnection policy • constant schedule • exponential schedule
- 31. Where do I get the driver ?! @doanduyhai 31 $ npm install cassandra-driver
- 32. Common Usage! @doanduyhai 32 var cassandra = require('cassandra-driver'); var client = new cassandra.Client({contactPoints: [’192.168.0.12', ’node2'], keyspace: ’my_keyspace'}); var query = 'SELECT email, last_name FROM users WHERE login=?'; client.execute(query, [’jdoe'], function(err, result) { console.log('got user with email ' + result.rows[0].email); });
- 33. API! @doanduyhai 33 Insert/Update var query = ‘’INSERT INTO sensor_data(id,date,value) VALUES(?, ?, ?)’’; client.query(query, [‘mySensor’, ‘2014-10-15 12:00:00’, 34.5], {prepare: true, consistency: cassandra.types.consistencies.one}, function(err) { //error handling });
- 34. API! @doanduyhai 34 Select var query = ‘’SELECT * sensor_data WHERE id = ?’’; client.query(query, [‘mySensor’], {prepare: true, consistency: cassandra.types.consistencies.one}, function(err, result) { result.rows.forEach(function(row) { console.log(‘value = ‘ + row.value); }); });
- 35. API! @doanduyhai 35 Client creation new cassandra.Client( { policies: {}, // load balancing, retry, reconnection queryOptions: {}, // default consistency, fetchSize protocolOptions: {}, // port pooling: {}, // #connection/host socketOptions: {}, //timeout authProvider: {}, //plain text login/password, SSL maxPrepared: 500});
- 36. Streaming! @doanduyhai 36 var query = ‘’SELECT * FROM sensor_data‘’; var stream = client.stream(query, [ ], {autoPage: true}); Default fetchSize = 5000
- 37. Streaming! @doanduyhai 37 stream .on(‘end’, function() { //no more data }) .on(‘readable’, function() { while (row = this.read()) { // do something with the row } }) .on(‘error’, function(err) { // process error });
- 38. Types! @doanduyhai 38 Cassandra Javascript bigint Long (dCodeIO) blob Buffer boolean Boolean counter Long (dCodeIO) Decimal Buffer Double Number Float Number int Number list Array map Object set Array Cassandra Javascript text String timestamp Date timeuuid String uuid String varchar* String varint* Buffer ascii* String
- 39. Special types! @doanduyhai 39 var cassandra = require('cassandra-driver'); //generate a new v4 uuid var id1 = cassandra.types.uuid(); //generate a new v1 uuid var id2 = cassandra.types.timeuuid(); //big int value var bigIntValue = new cassandra.types.Long.fromString("5764607523034211");
- 40. Code demo
- 41. ! " ! Q & R
- 42. Thank You @doanduyhai duy_hai.doan@datastax.com