1. Relational Grid Monitoring Architecture (R-GMA)
Valeria Ardizzone
INFN Catania
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2. Grid Monitoring Architecture(GMA)
The Producer stores its location (URL) in the Registry.
PRODUCER
Store location
The Consumer looks up producer URLs in the Registry.
REGISTRY
The Consumer contacts the Producer to get all the data or the Consumer can listen to the Producer for new data.
Transfer Data
CONSUMER
Lookup location
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3. R-GMA within Testbed
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4. R-GMA: Schema-Registry-Mediator
SCHEMA : it holds the names and definitions of all of the tables in the virtual database, and their authorization rules.
R-GMA Server
VIRTUAL DATABASE
TABLE 1,Producer P1 details
TABLE 2,Producer P1 details
TABLE 2,Producer P2 details
TABLE 2,Producer P3 details
TABLE 3,Producer P2 details
TABLE 3,Producer P1 details
TABLE 3,Producer P3 details
REGISTRY
TABLE 1, Colum defs
TABLE 2, Colum defs
TABLE 3, Colum defs
TABLE 4, Colum defs
SCHEMA
REGISTRY: It holds the details of all producers that are publishing to tables in the virtual database and it also holds the details of “continuous” consumers.
MEDIATOR
MEDIATOR: a set of rules for deciding which data providers to contact for any given query.
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5. R-GMA: Producer-Consumer
Producers: are the data providers for the virtual database. Writing data into the virtual database is known as publishing, and data is always published in complete rows, known as tuples. There are three types of producer: Primary, Secondary and On-demand.
R-GMA Server P1
VIRTUAL DATABASE C1
TABLE 1,Producer P1 details
TABLE 2,Producer P1 details
TABLE 2,Producer P2 details
TABLE 2,Producer P3 details
TABLE 3,Producer P2 details
TABLE 3,Producer P1 details
TABLE 3,Producer P3 details
REGISTRY
TABLE 1, Colum defs
TABLE 2, Colum defs
TABLE 3, Colum defs
TABLE 4, Colum defs
SCHEMA
SQL “INSERT” P2
SQL “SELECT”
MEDIATOR P3 C2
Consumer: represents a single SQL SELECT query on the virtual database. The query is matched against the list of available producers in the Registry. The consumer service then selects the best set of producers to contact and sends the query directly to each of them, to obtain the answer tuples.
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6. Producer Types Primary Producer C Secondary Producer P C
User Code
Producer API
Producer Service
Tuple Storage C
Control and inserted tuples
Queries
Tuples
Secondary Producer
User Code
Producer API
Producer Service
Tuple Storage C
Control only
Queries
Tuples
SELECT * P
On-Demand Producer
User Code
Producer API
Producer Service C
Control only
Queries
Tuples
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7. Query and Storage Types
Continuous: as soon as new data becomes available it is broadcast to all interested parties.
Latest: correspond to intuitive idea of current information.
History: return time sequenced data.
TABLE 1,Producer P1 details
TABLE 2,Producer P1 details
TABLE 2,Producer P2 details
TABLE 2,Producer P3 details
TABLE 3,Producer P2 details
TABLE 3,Producer P1 details
TABLE 3,Producer P3 details
REGISTRY
Tuple-store can be in Memory or Database P1
LATEST RETENTION PERIOD (LRP) and
HISTORY RETENTION PERIOD (RTP)
allow producers to periodically purge old tuples, and to give a precise meaning to the “current state”.
Latest-store
Continuous&History-store
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8. Store table description
Continuous
Producer API
Insert
Producer Servlet
Schema
TableName
Value 1
Value 2
TableName
Column
SQL “CREATE TABLE”
SQL “INSERT”
Store location
Store table description
TableName
Value 1
Value 2
Registry
Continuous
TableName
URL
Predicate
Lookup location
Consumer API
Query
Consumer Servlet
TableName
Value 1
Value 2
SQL “SELECT”
TableName UK
RAL
Alice
Result Set
TableName
Value 1
Value 2
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9. Store table description
History or Latest
Producer API
Insert
Producer Servlet
Schema
TableName
Value 1
Value 2
TableName
Column
SQL “CREATE TABLE”
SQL “INSERT”
Store location
Store table description
TableName
Value 1
Value 2
Registry
Query
TableName
URL
Predicate
Lookup location
Consumer API
Query
Consumer Servlet
TableName
Value 1
Value 2
SQL “SELECT”
TableName UK
RAL
Alice
Result Set
TableName
Value 1
Value 2
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10. R-GMA APIs APIs exist in Java, C, C++. They include methods for…
For clients (servlets contacted behind the scenes)
They include methods for…
Creating consumers
Creating primary and secondary producers
Setting type of queries, type of produces, retention periods, time outs…
Retrieving tuples, inserting data …
You can create your own Producer or Consumer.
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11. The R-GMA Browser The easiest way to try out R-GMA.
It is installed on the machine running the Registry and Schema:
Using the Browser you can do the following.
Browse the tables in the schema.
Look at the table definitions.
See all the available producers for a table.
Query a table.
Query only selected producers.
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12. https://rgmasrv.ct.infn.it:8443/R-GMA
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13. References RGMA exercises on PI2S2 Wiki:
Schema
gLite 3.0 User Guide
R-GMA home page
R-GMA in EGEE
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14. Questions…
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