solr index size issue

[sara hajili]

hi i have a about 500 doc that stored that in solr.
when i added this 500 doc i see solr index size it was  about 300 KB .
but it become bigger more and more ,and now after about 2 hours solr index
size become 3500KB . i did n't add any new doc to solr. but index size
become bigger and bigger.why solr treat in this way?
why solr index size become bigger and bigger without adding  any new doc?