3. The method of claim 1 , further comprising: partitioning each of a plurality of log streams into a sequence of records having corresponding intervals; and for each of the intervals, performing: determining a number of times the unique term occurs in one or more records of the log streams corresponding to the interval; selecting, based on the number of times, one of a plurality of different types of operations that the computer is configured to perform to characterize occurrences of terms in a record; and generating the information of the one of a bit-array data structure, a min-wise independent permutation locality sensitive hashing (MinHash) data structure, and a histogram data structure characterizing occurrences of the unique term in the one or more records of the log streams corresponding to the interval using the selected one of the plurality of different types of operations.
4. The method of claim 3 , further comprising: repeating the determining, the selecting, and the generating for each unique term occurring in the one or more records of the log streams corresponding to the interval, wherein the generating the estimate for the number of occurrences of the logical combination of terms in the defined interval of records for each of the logical combinations of terms in the set uses the information of the one of a bit-array data structure, a min-wise independent permutation locality sensitive hashing (MinHash) data structure, and a histogram data structure characterizing occurrences of each unique term among the terms in the logical combination of terms defined by the search query.