I am trying to understand the effect of fuzziness in fuzzy search using span_near multiple clauses.
Here I am doing a document count. Here is one query
GET wikipedia-20200820/_search
{
"query":{
"bool":{
"must":[
{
"span_near":{
"clauses":[
{
"span_multi":{
"match":{
"fuzzy":{
"text":{
"value":"labor",
"fuzziness":"2"
}
}
}
}
},
{
"span_multi":{
"match":{
"fuzzy":{
"text":{
"value":"unionism",
"fuzziness":"2"
}
}
}
}
},
{
"span_multi":{
"match":{
"fuzzy":{
"text":{
"value":"among",
"fuzziness":"2"
}
}
}
}
},
{
"span_multi":{
"match":{
"fuzzy":{
"text":{
"value":"negros",
"fuzziness":"2"
}
}
}
}
}
],
"slop":1,
"in_order":true
}
}
],
"filter": [
{ "term": { "ns": 0 }},
{ "range": { "timestamp": { "gte": "2020-01-01" }}}
]
}
}
}
that is giving me the expected result:
{
"took" : 284,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 1,
"relation" : "eq"
},
"max_score" : 2238.6646,
"hits" : [
{
"_index" : "wikipedia-20200820",
"_type" : "_doc",
"_id" : "GhxaT3UBz_UQYd3DEAJT",
"_score" : 2238.6646,
"_source" : {
"page_title" : "National Brotherhood of Workers of America",
"ns" : 0,
"page_id" : 28365131,
"redirect" : null,
"revision_id" : 965097134,
"revision_parent_id" : 891907364,
"timestamp" : "2020-06-29T11:26:55Z",
"contributor" : {
"username" : "JJMC89 bot III",
"id" : 35936988
},
"comment" : "Moving [[:Category:African-American history between emancipation and the Civil Rights Movement]] to [[:Category:African-American history between emancipation and the civil rights movement]] per [[Wikipedia:Categories for discussion/Speedy]]",
"sha1" : "q1rz1h5n6qk9cpdt5qf0zqrydd9vx7e",
"minor" : "TRUE",
"model" : "wikitext",
"format" : "text/x-wiki",
"text" : """The '''National Brotherhood of Workers of America''' (NBWA) was the largest body of organised [[African American]] workers in the [[United States of America]] in 1919.<ref>''Revolutionary radicalism: its history, purpose and tactics with an exposition and discussion of the steps being taken and required to curb it, being the report of the Joint Legislative Committee Investigating Seditious Activities'', filed 24 April 1920, in the Senate of the State of New York</ref>
==First congress==
The organisation was formed by T.J. Pree and R.T. Sims. [[Philip Randolph]] was also on the board.<ref name=yho>[http://hierographics.org/yourhistoryonline/yourhistoryonlineVIII.htm Your History online], accessed 17 August 2010</ref> The NBWA held its congress in [[Washington DC]] from 8–14 September 1919. There were 115 delegates primarily from the South. Three delegates were from the [[Industrial Workers of the World]] and fifteen from the Society for the Advancement of Trade Unionism among Negroes. No delegates were accepted from the [[American Federation of Labor]].<ref>''Revolutionary radicalism: its history, purpose and tactics with an exposition and discussion of the steps being taken and required to curb it, being the report of the Joint Legislative Committee Investigating Seditious Activities'', filed 24 April 1920, in the Senate of the State of New York</ref>
==Resolutions==
They passed resolutions to the effect that:
". . . The combination of black and white workers will be a powerful lesson to the capitalists of the solidarity of labor. It will show that labor, black and white, is conscious of its interests and power. This will serve to convert a class of worker, which has been used by the capitalist class
to defeat organised labor, into an ardent, class-conscious, intelligent, militant group."
"and be it further resolved, that we recommend to all the working people of our race, that they immediately make themselves acquainted more in detail with the
aims, objects and methods of said organization, the National Association for the Protection of
Labor Unionism Among Negroes, in order that we may, as speedily as possible, align ourselves with and join the industrial unions that have already organized, and help to organize new industrial unions in such industries where they do not yet exist.
"and be it further resolved, that we shall henceforth devote all our energies to building up the new order of society along lines above indicated, to the exclusion of efforts hitherto expended in other directions." <ref>''Revolutionary radicalism: its history, purpose and tactics with an exposition and discussion of the steps being taken and required to curb it, being the report of the Joint Legislative Committee Investigating Seditious Activities'', filed 24 April 1920, in the Senate of the State of New York</ref>
The NBWA functioned as an independent Union, drawing most of its support from shipyard and dock workers in the [[Tidewater region of Virginia]] area.<ref>''Crisis'', November 1951, p626</ref> The union dissolved in 1921, under pressure from the American Federation of Labor.<ref name=yho/>
==References==
{{reflist}}
[[Category:African-American leftism]]
[[Category:African-American history between emancipation and the civil rights movement]]
[[Category:Trade unions established in 1919]]
[[Category:Trade unions disestablished in 1921]]
[[Category:African-American trade unions]]"""
}
}
]
}
}
Although it is documented that the fuzziness parameter represents Edit Distance / Levenshtein Distance, it seemed inconsistent to me. Then to understand the effect of fuzziness I tried to change the some single term in the query and sometimes changed the fuzziness parameter, keeping everything else same.
I am summarizing some changes I tried in the query in the following table and whether or not the query resulted in the same result or not:
+----------------+---------------+-----------+---------------+-----------------------------+
| iniatial_query | updated_query | fuzziness | edit_distance | elastic_returns_same_result |
+----------------+---------------+-----------+---------------+-----------------------------+
| "labor" | "labot" | 2 | 1 | Yes |
| "labor" | "labori" | 2 | 1 | No |
| "labor" | "lab" | 2 | 2 | No |
| "labor" | "lab" | 3 | 2 | No |
| "labor" | "lab" | 4 | 2 | No |
| "labor" | " labor" | 2 | 1 (1 space) | Yes |
| "labor" | " labor" | 1 | 1 (1 space) | Yes |
| "labor" | " labor" | 2 | 2 (2 space) | No |
| "unionism" | "unionismi" | 2 | 1 | Yes |
| "unionism" | "unionismi" | 1 | 1 | Yes |
| "among" | "amonng" | 2 | 1 | Yes |
| "among" | "amonng" | 1 | 1 | Yes |
| "among" | "amonnng" | 2 | 2 | No |
| "among" | "amonnng" | 3 | 2 | No |
| "among" | "amonnng" | 10 | 2 | No |
+----------------+---------------+-----------+---------------+-----------------------------+
Can someone explain what is the effect of fuzziness parameter on the query?
