While in trace mode, you can issue a pause command to pause the stream processing loop. Pausing the loop allows you to examine the stream in a static state.
While the Event Stream Processor is in trace mode, the stream processing mechanism checks for a pause request as it enters each processing group location. Once you issue a pause command, the stream pauses and the does not resume the loop until you allow it to continue. When the Event Stream Processor is paused, no calculations happen. Any transactions in the streams' output buffers are still consumable by subscribers. Publishing to the paused stream continues until the stream's input buffers are full.
If the stream is engaged in actual processing when the pause is requested, processing continues until it enters the next location.
Streams are not affected by a pause request when in an I/O location. For example, the stream pauses automatically in the INPUT location if there are no transactions in the input queue and in the OUTPUT location if the output queue is full.
The stream may move between the I/O locations to a processing location even when it is paused. If there is a slow subscriber on a stream, the stream's output fills up, and the stream remains in the OUTPUT location, until the buffer space becomes available. If the stream in this location receives a pause request, the request is ignored. If the stream's subscriber takes a transaction off the output buffer after this request, the stream deposits its current output transaction on the buffer and goes to the INPUT location. At this point, after entering the INPUT location, the stream recognizes the pause request. No new data is processed after the pause request, but the stream does change its location.
Pause metadata streams like any other stream. No updates should come from these streams while the Event Stream Processor is paused, except for _ESP_RunUpdates.
esp_client> check_pause Platform is not paused esp_client> pause esp_client> check_pause PAUSED esp_client> run esp_client> check_pause Platform is not paused