DeduplicateRecord

Description:

This processor attempts to deduplicate a record set in memory using either a hashset or a bloom filter. It operates on a per-file basis rather than across an entire data set that spans multiple files.

Tags:

text, record, update, change, replace, modify, distinct, unique, filter, hash, dupe, duplicate, dedupe

Properties:

In the list below, the names of required properties appear in bold. Any other properties (not in bold) are considered optional. The table also indicates any default values, and whether a property supports the NiFi Expression Language.

Name	Default Value	Allowable Values	Description
Deduplication Strategy	single	Single File Multiple Files	The strategy to use for detecting and isolating duplicate records. The option for doing it across a single data file will operate in memory, whereas the one for going across the enter repository will require a distributed map cache.
Distributed Map Cache client		Controller Service API: DistributedMapCacheClient Implementations: HBase_2_ClientMapCacheService CassandraDistributedMapCache HBase_1_1_2_ClientMapCacheService DistributedMapCacheClientService CouchbaseMapCacheClient HazelcastMapCacheClient RedisDistributedMapCacheClientService	This configuration is required when the deduplication strategy is set to 'multiple files.' The map cache will be used to check a data source such as HBase or Redis for entries indicating that a record has been processed before. This option requires a downstream process that uses PutDistributedMapCache to write an entry to the cache data source once the record has been processed to indicate that it has been handled before. This Property is only considered if the <Deduplication Strategy> Property has a value of "multiple".
Cache Identifier			This option defines a record path operation to use for defining the cache identifier. It can be used in addition to the hash settings. This field will have the expression language attribute "record.hash.value" available to it to use with it to generate the record path operation. Supports Expression Language: true (will be evaluated using flow file attributes and variable registry) This Property is only considered if the <Deduplication Strategy> Property has a value of "multiple".
Record Reader		Controller Service API: RecordReaderFactory Implementations: JsonPathReader AvroReader XMLReader WindowsEventLogReader ReaderLookup Syslog5424Reader GrokReader ScriptedReader CSVReader SyslogReader ParquetReader JsonTreeReader CEFReader	Specifies the Controller Service to use for reading incoming data
Record Writer		Controller Service API: RecordSetWriterFactory Implementations: AvroRecordSetWriter ScriptedRecordSetWriter JsonRecordSetWriter ParquetRecordSetWriter RecordSetWriterLookup FreeFormTextRecordSetWriter XMLRecordSetWriter CSVRecordSetWriter	Specifies the Controller Service to use for writing out the records
Include Zero Record FlowFiles	true	true false	When converting an incoming FlowFile, if the conversion results in no data, this property specifies whether or not a FlowFile will be sent to the corresponding relationship
Record Hashing Algorithm	SHA-256	None SHA-256 SHA-512	The algorithm used to hash the combined set of resolved RecordPath values for cache storage.
Filter Type	hash-set	HashSet BloomFilter	The filter used to determine whether a record has been seen before based on the matching RecordPath criteria. If hash set is selected, a Java HashSet object will be used to deduplicate all encountered records. If the bloom filter option is selected, a bloom filter will be used. The bloom filter option is less memory intensive, but has a chance of having false positives. This Property is only considered if the <Deduplication Strategy> Property has a value of "single".
Filter Capacity Hint	25000		An estimation of the total number of unique records to be processed. The more accurate this number is will lead to fewer false negatives on a BloomFilter. This Property is only considered if the <Filter Type> Property has a value of "bloom-filter".
Bloom Filter Certainty	0.10		The desired false positive probability when using the BloomFilter type. Using a value of .05 for example, guarantees a five-percent probability that the result is a false positive. The closer to 1 this value is set, the more precise the result at the expense of more storage space utilization.

Dynamic Properties:

Dynamic Properties allow the user to specify both the name and value of a property.

Name	Value	Description
RecordPath	An expression language statement used to determine how the RecordPath is resolved. The following variables are availible: ${field.name}, ${field.value}, ${field.type}	The name of each user-defined property must be a valid RecordPath. Supports Expression Language: false

Relationships:

Name	Description
duplicate	Records detected as duplicates in the FlowFile content will be routed to this relationship
non-duplicate	If the record was not found in the cache, it will be routed to this relationship
failure	If unable to communicate with the cache, the FlowFile will be penalized and routed to this relationship
original	The original input FlowFile is sent to this relationship unless there is a fatal error in the processing.

Reads Attributes:

None specified.

Writes Attributes:

Name	Description
record.count	The number of records processed.

State management:

This component does not store state.

Restricted:

This component is not restricted.

Input requirement:

This component requires an incoming relationship.

System Resource Considerations:

Resource	Description
MEMORY	The HashSet filter type will grow memory space proportionate to the number of unique records processed. The BloomFilter type will use constant memory regardless of the number of records processed.
CPU	If a more advanced hash algorithm is chosen, the amount of time required to hash any particular record could increase substantially.