ODBC Request Monitoring and Cancellation
Request monitoring is supported for the ODBC app server in MarkLogic 10.0-9 and later. The following ODBC meters will be recorded for ODBC Requests:
Meter |
Description |
|---|---|
odbcRowsSent |
The number of rows sent from the server over the network |
odbcBytesSent |
The total number of bytes sent from the server over the network |
Prior to this feature, the Modules database assigned to an ODBC server served no purpose. Now, a file named /default.api is looked for in the Modules root - whether that be the filesystem or a Modules database - and the configuration defined in that file is heeded to.
When a query comes in over ODBC, the odbcRowsSent and odbcBytesSent meters and their values are output in the ODBC app server request log, given that Request Monitoring is enabled in /default.api.
Request cancellation is now enabled for ODBC server as well. The /default.api will take in unsigned long values as limits for odbcRowsSent and odbcBytesSent. If the number of rows or bytes sent exceed the limits defined in /default.api, the sending of rows over the network ends prematurely and SQL-ODBCREQLIMIT is thrown. elapsedTime is also supported for cancellation, and XDMP-EXTIME is thrown if the time limit is exceeded. lockCount and readSize are not relevant for ODBC.
These values are purely e-node metrics and are not recorded on any d-nodes.
Configuration example:
With the following /default.api in the Modules root, a query will be canceled for one of these reasons:
Run time exceeds 3 seconds.
The number of bytes sent to the client exceeds 200000.
The number of rows sent to the client exceeds 10000.
{
"monitoring": {
"general": {
"enabled": true
},
"limits" : {
"elapsedTime" : 3,
"odbcBytesSent": 200000,
"odbcRowsSent": 10000
}
}
}