lucene - does elasticsearch have compound indexes? -


i'm wondering if elasticsearch needs have compound indexes defined priori. compound index, mean mongodb has.

db.collection.ensureindex( { field1: 1, field2: 1, field3: 1 } )

or mysql db has.

create index adhoc_index on mytable(field1, field2, field3);

so data dealing flat (most of csv format). looks following (for completeness).

field1, field2, ..., fieldn

the number of fields arbitrary. 1 dataset may have 10 fields, 20, 1000. convert each row json document looks following.

{  "field1" : "value1",  "field2" : "value2",  ...  "fieldn" : "valuen" }

denote a, b, , c 3 mutually exclusive subsets of fields: {field1, field2, ..., fieldn}. @ given time, have build dynamic query filters records a=a, b=b, , c=c.

for example,

  • a = {field1}, b = {field2, field3}, c = {field6}
  • a = {field2}, b = {field1}, c = {field1000, field50}

so elasticsearch dsl query may following (not sure if correct myself, illustrate).

"bool" : {  "must" : [   {"term" : { "field1" : "val1" },   {"term" : { "field2" : "val2" },   {"term" : { "field3" : "val3" },   {"term" : { "field4" : "val4" }  ] }

basically, query says, "give me documents field1=val1, field2=val2, field3=val3, field4=val4".

the reason why ask elasticsearch because not find clear answer searching on internet compound indexes. needed?

i'm evaluating mongodb , mysql well, , don't think work situation because these compound/composite indexes have defined priori, , won't have information until runtime group of fields need indexed optimize query speed. of course, mysql, once find out group of fields need indexed (and in order), can go create index, may take long time if dataset large (number of rows > 1 million).

do compound index feature out of box elastic search? meaning, won't have touch index mapping file/definition?

elasticsearch doesn't have composite indexes, it's efficient @ querying multiple indexes , intersecting them (intersecting bit-vectors ftw).

most of time, composite indexes not needed, cases mentioned query 4 different fields. elasticsearch happily query 4 different indexes , intersect results in efficient manner. in experience performance matches , surpasses of mongodb in similar situations.

if absolutely must have composite index, might consider indexing auxiliary field value composite of values want index.


Comments

Post a Comment

Popular posts from this blog

android - Get AccessToken using signpost OAuth without opening a browser (Two legged Oauth) -

i using signpost oauth access data magento server. have read various tutorials on same , reach point open browser user can enter credentials. however, per requirement have automate part. hence, user should not browser page. have set-up done on server side ( magento ), hit url , returned call page. same through program in android. i have tried below, consumer = new commonshttpoauthconsumer(key, secret); provider = new commonshttpoauthprovider(oauth_init_url,access_token_url, authorize_url); try { provider.retrieverequesttoken(consumer, oauth.out_of_band); log.d("tokens" , consumer.gettoken() + " -- " + consumer.gettokensecret()); } and request tokens. dont know how bypass next step. tried directly accessing accesstoken (stupid of me) provider.retrieveaccesstoken(consumer, "mycallback://callback"); no luck, ends in oauth.signpost.exception.oauthnotauthorizedexception: authorization failed (server replied 401). ...
Read more

org.mockito.exceptions.misusing.InvalidUseOfMatchersException: mockito -

getting error org.mockito.exceptions.misusing.invaliduseofmatchersexception: invalid use of argument matchers! 1 matchers expected, 2 recorded. exception may occur if matchers combined raw values: //incorrect: somemethod(anyobject(), "raw string"); when using matchers, arguments have provided matchers. example: //correct: somemethod(anyobject(), eq("string matcher")); at when( getprogramservice .callservice(any(getprogramtype.class))) .thenreturn(jaxbresponse); please explain error , possible resolution the code posted looks fine; don't see problem it. code before or above causing exception. key here: invalid use of argument matchers! 1 matchers expected, 2 recorded. any , used above, doesn't return "special kind of null" or "special kind of getprogramtype"; don't exist. instead, returns null , side effect puts matcher on stack. whe...
Read more

google shop client API returns 400 bad request error while adding an item -

i'm working on solution add items in google shopping market java application. following tutorial real mess because of missing classes of laste release, after setting 1.5-beta maven managed make base example typecheck correctly classes. still can make simple task of adding 1 item. instead of posting whole code i'm posting part creates product feed. private product createproduct(string id) { product product = new product(); product.title = "red wool sweater"; product.content = new content( "text", "comfortable , soft, sweater keep warm on " + "cold winter nights. red , blue stripes."); product.appcontrol = new appcontrol(); product.appcontrol.addrequireddestination("productads"); product.externalid = id; product.lang = "it"; product.country = "it"; product.condition = "nuovo"; product.price = new price("eu...
Read more