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message is a string field that can contain any sorts sort of text (usually the original log line or some other free text)
@timestamp is a date field, on which log retention is based. If it's not present, Logsene will add a timestamp upon retentionevent receipt
All of these fields are optional, but their use is strongly encouraged. If found in logs with low-enough cardinality, all distinct values of these fields will be loaded and shown in the UI as filters and thus allowing one to very quickly narrow down the search.
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