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Mange SequoiaDB Process

Concept

Engine Dispatchable Unit is the carrier of tasks in SequoiaDB. Generally, EDU is an independent thread.

Each EDU can be used to execute users' requests or execute system internal maintenance tasks.

EDU is independent to each other. One EDU is charged for one user session. One user session is fixed on one EDU on one data node.

Each EDU has a thread-unique and 64-bit integer ID called "EDU ID".

There are two kinds of EDU: user EDU and system EDU, respectively representing threads that executes user task and threads that executes system task.

User EDU

User EDU is a thread executes user task. It is also called Agent

In SequoiaDB, ther are differnt kinds of agetns as follow:

Name Type Description
Agent Agent Agent thread is charged for requests of svcname service. Generally, the request is directly sent by user.
ShardAgent Shard agent Shard agent thread is charged for requests of shardname service. Generally, the request is directly sent from coord node to data node.
CoordAgent Coord agent Coord agent thread is charged for request of svcname service. Generally, the request is directly sent from user to coord node and only acts on coord node.
ReplAgent Replication agent Replication agent thread is charged for request of replname service. Generally, the request is directly sent from data master node to data slave node and acts on non-coord node.
HTTPAgent HTTP agent HTTP agent thread is charged for request of httpname service. Generally, the request is directly sent by user.

System EDU

System EDU is a kind of threads that maintains data structures in the system and guarantee the consistency of data and configuration. Generally, it is invisible to users.

In SequoiaDB, there are different kinds of EDU. The following EDU are just part of them:

Name Type Description
TCPListener Service listener The duty of this thread is to listen to svcname service, and start agent threads.
HTTPListener HTTP listener The duty of this thread is to listen to httpname service, and start agent threads.
Cluster Cluster management Cluster management thread is used to maintain the infrastructure of clusters, and start ReplReader threads and ShardReader threads.
ReplReader Replication listener ReplReader is charged for request of replname service, and start ReplAgent threads.
ShardReader Shard listener ShardReader is charged for request of shardname service, and start ShardAgent threads.
LogWriter Log writer LogWriter thread is used to write data from log cache to log file.
WindowsListener Windows event listener It is owned by Windows environment. It is used to listen to events defined by SequoiaDB.
Task Background task It is a kind of threads that cope with background tasks. For example, data split
CatalogMC Catalog main controller CatalogMC thread is used to receive and send requested sent to catalog nodes.
CatalogNM Catalog node maintainer CatalogNM thread is used to cope with requests relative to cluster information within catalog nodes.
CatalogManager Catalog manager CatalogManager thread is used to cope with requests relative to metadata information within catalog nodes.
CatalogNetwork Catalog network listener CatalogNetwork thread is used to listen to requests of catalogname service in coord network.
CoordNetwork Coord network listner CoordNetwork thread is used to listen to shard requests.

Monitorinf

Users can use sessions snapshot to monitor system and user EDU.

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About Us

SequoiaDB is a financial-level distributed database vendor and is the first Chinese database listed in Gartner’s Magic Quadrant OPDBMS report. SequoiaDB has recently released version 3.0.
SequoiaDB is now penetrating the vertical sector Financial Industry quickly and had more than 50 banking clients and hundreds of enterprise customers in industries including government, telecommunication, Internet and IoT.

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