Evaluation of Massively Scalable Database Management Systems for Erlang

Evaluation of Massively Scalable Evaluation of Massively Scalable Database Management Systems for Database Management Systems for

ErlangErlang

Fifth ACM SIGPLAN Erlang WorkshopFifth ACM SIGPLAN Erlang WorkshopPortland, September 16Portland, September 16thth, 2006, 2006

Emil [email protected]

ContentsContents

• MnesiaMnesia• DBMS surveyDBMS survey• Open Source AlternativesOpen Source Alternatives• ConclusionsConclusions

MneMnessiaia

• Primarily designed as a in-memory databasePrimarily designed as a in-memory database– Very fast lookup times

• Great connectivity/interface to ErlangGreat connectivity/interface to Erlang– Tight coupling to Erlang

• Limited to 4 GB table size (8GB on 64 Bit Limited to 4 GB table size (8GB on 64 Bit machines)machines)

• Lacking in ability to maintain constraintsLacking in ability to maintain constraints• Awkward to modify schemasAwkward to modify schemas

DBMS SurveyDBMS Survey

• Important attributesImportant attributes– Safety Mechanisms– Replication– Large Storage Capabilities– Maintaining Logical Constraints– Erlang Interface

Open Source AlternativesOpen Source Alternatives

• Berkeley DBBerkeley DB– Embedded databases

• MySQLMySQL– Web applications

• PostgreSQLPostgreSQL– Complex databases / Web applications

• IngresIngres– Enterprise grade databases

How do we know which one to use???How do we know which one to use???

Berkeley DBBerkeley DB

• Pros:Pros:– Good for term storage– Fast lookups with memory cache

• Cons:Cons:– Does not support constraints– Application involvement needed for replication– Limited in size capabilites (256 GB/DB and 4GB/record)– Lots of things left to the using application

• Erlang:Erlang:– Several open source drivers exist

MySQLMySQL

• Pros:Pros:– MySQL clusters– Supports failover (however, additional scripting needed)

• Cons:Cons:– Some storage engines may force invalid data into valid– Size limitations (different for different storage engines)– No partial recovery

• Erlang:Erlang:– The Erlang ODBC driver is available– A primitive driver exists through the YXA project.– Erlang Training and Consulting will soon be releasing its

driver.

PostgreSQLPostgreSQL

• Pros:Pros:– Storage capabilities– Supports fail and switchover (with additional software)– Good constraint system– Soon an open source driver available

• Cons:Cons:– Some limitations in replicating large objects– No partial recovery

• Erlang:Erlang:– Erlang Training and Consulting has released its driver– The Erlang ODBC driver is available

IngresIngres

• Pros:Pros:– Supports failover– Support partial recovery of inconsistent tables– Can attempt automatic resolution of inconsistencies– Replication granularity– Great constraint system– Clustering capabilities

• Cons:Cons:– Only interface is through Erlang ODBC application

• ErlangErlang– The Erlang ODBC driver is available

ConclusionsConclusions

• We evaluated the questionnaire results using We evaluated the questionnaire results using a method called the Analytical Hierarchy a method called the Analytical Hierarchy ProcessProcess– Evaluation method invented by Dr. Thomas Saaty in the

1970's– Based on pairwise comparison of alternatives to reduce

complexity

DBMS ScoreIngres 0.37

PostgreSQL 0.35MySQL 0.19

BerkeleyDB 0.09


From the survey, we conclude Erlang Users are From the survey, we conclude Erlang Users are not giving up using Mnesia. Asked what not giving up using Mnesia. Asked what

survey participants use when Mnesia is not survey participants use when Mnesia is not enough, two replies we got were…enough, two replies we got were…

“We still use Mnesia, with care.”

In order not to complicate design, “one of our applications uses

Mnesia to store about 200,000,000 rows/record. The database consists

of two logical tables: one set of 512 fragments is used for data, and another consisting of 128

fragments is used to store indexes.”


• Is a comparison of Berkeley DB and relational Is a comparison of Berkeley DB and relational databases fair?databases fair?

• What licenses are available for the DBMSs?What licenses are available for the DBMSs?

Questions ?Questions ?

SummarySummary

• MnesiaMnesia• DBMS surveyDBMS survey• Open Source AlternativesOpen Source Alternatives• ConclusionsConclusions

Evaluation of Massively Scalable Database Management Systems for Erlang

Documents

Transcript of Evaluation of Massively Scalable Database Management Systems for Erlang