Gaining Insights into Server Cache

Overview

The $info endpoint offers comprehensive insights into the server's cache usage, active user sessions, and internal server metrics. This endpoint is instrumental for developers and administrators to monitor and manage the application's performance and data accessibility effectively.

Properties Returned

General Properties

The $info endpoint returns structured information as outlined in the following table:

Property	Type	Description
cacheSize	Number	Total allocated cache size in bytes.
usedCache	Number	Amount of cache currently used in bytes.
entitySetCount	Number	Number of entity selections currently stored.
entitySet	Array	Information on active entity selections stored within the server's cache.
ProgressInfo	Array	Operational progress indicators that may impact server performance.
sessionInfo	Array	Data on active user sessions, including session duration and expiration.
memMetrics	Array	Detailed memory usage statistics related to client and server processes.
privileges	Object	An object with a "privileges" property (collection of objects). Each object of the collection has a "privilege" property with a privilege name of the user session as value.

entitySet Details

The entitySet provides detailed information about each entity set stored in the cache:

Property	Type	Description
id	String	Unique identifier for the entity set.
dataClass	String	Name of the dataclass associated with the entity set.
selectionSize	Number	Number of entities within the set.
sorted	Boolean	Indicates if the set is sorted.
refreshed	Date	Timestamp when the entity set was last accessed or refreshed.
expires	Date	Expiry timestamp after which the entity set may be cleared from cache.

Additionally, for creating or releasing an entity set from the cache:

• Creating an Entity Set: Use $method=entityset to initiate a new entity selection within the cache, specifying the desired parameters for entity retrieval.

• Releasing an Entity Set: To remove an entity set from the cache, employ $method=release, ensuring the specific set is targeted for clearance.

info

The server automatically generates certain entity selections for internal optimizations. Therefore, the entity sets you manually create are part of a broader collection managed by the system.

ProgressInfo Details

The ProgressInfo provides information about ongoing operations that may affect server performance:

Property	Type	Description
UserInfo	String	Identifier for the type of progress (e.g., index or flush).
SessionCount	Number	Number of sessions affected by this operation.
Title	String	Title or name of the operation, if applicable.
CanInterrupt	Boolean	Indicates whether the operation can be interrupted.

sessionInfo Details

The sessionInfo details each active user session to help monitor access and system usage:

Property	Type	Description
sessionID	String	Unique identifier for the user session.
lifeTime	Number	Duration the session is set to remain active, in seconds.
expiration	Date	Timestamp when the session is scheduled to expire.

memMetrics Details

The memMetrics provides a detailed breakdown of memory usage across different server processes, particularly focusing on client interactions and REST API handlers:

Key	Type	Description
clients	Object	An object that currently has no data (empty). Future implementations may populate this with client-specific memory usage data.
processes	Object	Memory usage broken down by server processes such as the Client Manager and REST Handler.
methods	Object	Memory usage associated with internal methods.
total	Object	Cumulative memory metrics across all processes and methods.

Example Context: Client Manager and REST Handler

In the processes section, memory usage is detailed for key server components like the Client Manager and the REST Handler:

• Client Manager: Manages client connections and data transactions.

  • methods: Details internal methods and their memory usage.
  • total: Aggregates the memory usage for the entire process.

• REST Handler: Manages REST API requests and responses.

  • methods: Specific to handling REST requests, including caching and entity management.
  • total: Summarizes memory usage directly attributed to REST operations.

Sample Usage Example in Postman

How to Use:

• Method: GET
• URL: {{ApiEndpoint}}/rest/$info

The response structure for the $info endpoint looks something like this in practice:

{
    "cacheSize": 209715200,
    "usedCache": 328760,
    "entitySetCount": 1,
    "entitySet": [
        {
            "id": "9BCEC36AD6ED4104BE817C47C360AB0D",
            "dataClass": "Users",
            "selectionSize": 10,
            "sorted": false,
            "refreshed": "2024-05-12T00:21:38.575Z",
            "expires": "2024-05-12T02:21:38.575Z"
        }
    ],
    "ProgressInfo": [
        {
            "UserInfo": "flushProgressIndicator",
            "SessionCount": 0,
            "Title": "",
            "CanInterrupt": false
        },
        {
            "UserInfo": "indexProgressIndicator",
            "SessionCount": 0,
            "Title": "",
            "CanInterrupt": true
        }
    ],
    "sessionInfo": [
        {
            "sessionID": "00130D6E779E4681873A8B46B694C2DD",
            "lifeTime": 60,
            "expiration": "2024-05-12T01:03:34.942Z"
        },
        {
            "sessionID": "0024480DF07143F995C445C20470E901",
            "lifeTime": 60,
            "expiration": "2024-05-12T00:53:48.042Z"
        },
    ],
    "HTTPConnections": [],
    "privileges": [
        {
            "privilege": "guest"
        }
    ],
    "memMetrics": [
        {
            "clients": {},
            "processes": {
                "Client Manager": {
                    "methods": {
                        "[internal]": {
                            "entities": 0,
                            "entitySelections": 0,
                            "records": 0,
                            "selections": 0,
                            "bittables": 8
                        }
                    },
                    "total": {
                        "entities": 0,
                        "entitySelections": 0,
                        "records": 0,
                        "selections": 0,
                        "bittables": 8
                    }
                },
                "REST Handler: ": {
                    "methods": {
                        "[internal]": {
                            "entities": 0,
                            "entitySelections": 1,
                            "records": 0,
                            "selections": 1,
                            "bittables": 1
                        }
                    },
                    "total": {
                        "entities": 0,
                        "entitySelections": 1,
                        "records": 0,
                        "selections": 1,
                        "bittables": 1
                    }
                }
            },
            "methods": {
                "[internal]": {
                    "entities": 0,
                    "entitySelections": 0,
                    "records": 0,
                    "selections": 0,
                    "bittables": 8
                }
            },
            "total": {
                "entities": 0,
                "entitySelections": 1,
                "records": 0,
                "selections": 1,
                "bittables": 9
            }
        }
    ]
}