GLOBAL
¶Functions to create and manipulate probabilistic cardinality counters.
Namespace: | GLOBAL |
---|---|
Source File: | /scripts/base/bif/cardinality-counter.bif.bro |
hll_cardinality_add : function |
Adds an element to a HyperLogLog cardinality counter. |
hll_cardinality_copy : function |
Copy a HLL cardinality counter. |
hll_cardinality_estimate : function |
Estimate the current cardinality of an HLL cardinality counter. |
hll_cardinality_init : function |
Initializes a probabilistic cardinality counter that uses the HyperLogLog algorithm. |
hll_cardinality_merge_into : function |
Merges a HLL cardinality counter into another. |
hll_cardinality_add
¶Type: | function (handle: opaque of cardinality, elem: any ) : bool |
---|
Adds an element to a HyperLogLog cardinality counter.
Handle: | the HLL handle. |
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Elem: | the element to add. |
Returns: | true on success. |
See also: hll_cardinality_estimate
, hll_cardinality_merge_into
, hll_cardinality_init
, hll_cardinality_copy
hll_cardinality_copy
¶Type: | function (handle: opaque of cardinality) : opaque of cardinality |
---|
Copy a HLL cardinality counter.
Handle: | cardinality counter to copy. |
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Returns: | copy of handle. |
See also: hll_cardinality_estimate
, hll_cardinality_merge_into
, hll_cardinality_add
, hll_cardinality_init
hll_cardinality_estimate
¶Type: | function (handle: opaque of cardinality) : double |
---|
Estimate the current cardinality of an HLL cardinality counter.
Handle: | the HLL handle. |
---|---|
Returns: | the cardinality estimate. Returns -1.0 if the counter is empty. |
See also: hll_cardinality_merge_into
, hll_cardinality_add
, hll_cardinality_init
, hll_cardinality_copy
hll_cardinality_init
¶Type: | function (err: double , confidence: double ) : opaque of cardinality |
---|
Initializes a probabilistic cardinality counter that uses the HyperLogLog algorithm.
Err: | the desired error rate (e.g. 0.01). |
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Confidence: | the desired confidence for the error rate (e.g., 0.95). |
Returns: | a HLL cardinality handle. |
See also: hll_cardinality_estimate
, hll_cardinality_merge_into
, hll_cardinality_add
, hll_cardinality_copy
hll_cardinality_merge_into
¶Type: | function (handle1: opaque of cardinality, handle2: opaque of cardinality) : bool |
---|
Merges a HLL cardinality counter into another.
Note
The same restrictions as for Bloom filter merging apply,
see bloomfilter_merge
.
Handle1: | the first HLL handle, which will contain the merged result. |
---|---|
Handle2: | the second HLL handle, which will be merged into the first. |
Returns: | true on success. |
See also: hll_cardinality_estimate
, hll_cardinality_add
, hll_cardinality_init
, hll_cardinality_copy