The document discusses Cassandra drivers for .NET and C++. It describes how older Thrift-based drivers worked, the advantages of Cassandra's new asynchronous binary protocol, and examples of using the .NET driver. It also outlines plans for future driver development, including a new C++ driver built on Boost.Asio.

1. Sterowniki .NET i C++ dla
Apache Cassandra
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2. dr inż. Paweł Kapłański
Cognitum
p.kaplanski@cognitum.eu

3. Cognitum
Autoryzowany dystrybutor DataStax Enterprise w Polsce
Dostarczamy:
Big Data
Cloud

Wysoce skalowalne aplikacje w chmurze

Rozwiązania Big Data

Systemy zarządzania wiedzą

Aplikacje dedykowane

Rozwój oprogramowania i testowanie aplikacji

Konsulting IT
Semantics
strong partnerships:
Customers from: US, CH, FL, DE
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4. Spis treści (Agenda)
1.
2.
3.
4.
5.
6.
7.
Cassandra
Jak działają stare sterowniki oparte o Thrift
Asynchroniczność
Binarny protokół klient-serwer w Cassandrze
Przykład (driver .Net)
Plany na przyszłość
Driver C++
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5. Cassandra
1. noSql – BigTable (Google 2005)
2. Stworzona w FB – obecnie Apache
3. Rozproszona
4. Skalowalna - Duże (100PB) dane
5. Obecnie już istnieją instalacje po 1000 nodów
6. Symetryczna (odporna na awarie)
7. Klaster (możliwość instalacji „multidatacenter”)
8. Elastyczna – duże możliwości konfiguracji
9. CQL – Cassandra Query Language
– podobny do SQL
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6. Multidatacenter
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7. Typowa aplikacja (serwis www .Net)
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8. Ważne!
1. Driver to nie tyko „smart socket” - posiada
rozbudowaną logikę działania
2. Driver zarządza połączeniami do klastra
– load balancer
3. Użytkownik nie musi martwić się o
połączenie i strategię – wystarczy ze użyje
jednej z dostaraczanych np. RoundRobin
4. Driver potrafi automatycznie powtórzyć
zapytanie w razie potrzeby
5. Można tworzyć własne strategie
6. Lock-free (wysoka wydajność)
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9. Interfejsy C*: Thrift
1. IDL (interface definition language)
2. Pozwala na automatyczne generowanie
kodu w różnych językach
3. Sam Thrift to nie wszystko – trzeba
obsłużyć zapytania do klastra
4. Zapytanie blokuje połączenie
(podobnie jak zapytanie http)
w oczekiwaniu na odpowiedź
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10. Interfejsy C*: Protokół binarny
1.
Operacje asynchroniczne
2.
Pojedyncze polaczenie do 128
jednoczesnych zapytan
3.
Lepsze wykorzystanie zasobów (połączenia
są kosztowne)
4.
Cassandra może lepiej optymizować
5.
Wsparcie dla programowania
asynchronicznego – powszechne obecnie w
podejsciu client-server
6.
Zdarzenia z Cassandy są „pushowane”
•
zmiana schematu bazy
•
zmiana w topologii klastra
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11. Wspierane języki
1.
Native Protocol Drivers (Datastax)
•
Java driver (with ORM)
•
.Net driver (Cql2Linq, ORM)
•
Python
•
C++ Driver – early stage of development
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12. Przykład – połączenie (driver .Net)
1. public class NerdMovie {
[PartitionKey] public string Movie;
[ClusteringKey(1)] public string Director;
public string MainActor;
public int Year;
}
2. var cluster = Cluster.Builder().AddContactPoints("192.168.13.1", "192.168.13.1").Build();
3. using (var session = cluster.Connect("test")){
var nerdMovieTable = session.GetTable<NerdMovie>();
nerdMovieTable.CreateIfNotExists();
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13. Zapytania
var batch = session.CreateBatch();
batch.Append(nerdMovieTable.Insert(
new NerdMovie() { Movie = "Serenity", Director = "Joss Whedon", MainActor = "Nathan Fillion", Year = 2005 }));
batch.Append(nerdMovieTable.Insert(
new NerdMovie() { Movie = "Pulp Fiction", Director = "Quentin Tarantino", MainActor = "John Travolta", Year
= 1994 }));
batch.Append(nerdMovieTable.Insert(
new NerdMovie() { Movie = "Zero Charisma", Director = "Katie Graham", MainActor = "Nathan Fillion", Year = 2013
}));
var query = from m in nerdMovieTable select m;
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14. Wywołanie synchroniczne
batch.Execute();
var result = query.Execute();
foreach (var e in result)
Console.WriteLine("Movie " + e.Movie + "[" + e.Director + "]");
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15. Wywołanie asynchroniczne
ManualResetEventSlim ev = new ManualResetEventSlim();
batch.BeginExecute((ar1) => {
batch.EndExecute(ar1);
query.BeginExecute((ar2) => {
var result = query.EndExecute(ar2);
foreach (var e in result)
Console.WriteLine("Movie " + e.Movie + "[" + e.Director + "]");
ev.Set();
}, null);
}, null);
ev.Wait();
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16. Co dalej? (driver .Net)
Protokół binarny: wersja 2 (Cassandra 2.x)
-
Batch
-
Autentykacja poprzez SASL
-
Lekkie transakcje – implementacja protokołu
Paxos
IINSER … IF NOT EXISTS,
UPDATE … IF <column>=<value>
-
Strumieniowanie wyników
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17. Driver C++ (w drodze)
1. Wieloplatformowość (np. embedded)
2. Oparty o boost::asio
3. Mała liczba zależności od innych
bibliotek
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18. Kontakt
Cognitum | PL, Warszawa
office@cognitum.eu
+48 22 250 2541
www.cognitum.eu/semantics
abroad sales representatives:
Cognitum | CH, St. Gallen
swiss-office@cognitum.eu
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Cognitum | UK, Bristol
uk-office@cognitum.eu
The company, product and service names used in this web site are for identification purposes only.
All trademarks and registered trademarks are the property of their respective owners.