Hi there Lucene samurai! *I was wondering how important is single segment merging for search time performance compared to a more modest merging goal like merging down to just 4 segment. *
Currently my system merges every evening, it takes ~1-2 hours, and invalidates the File-system cache. What would happen if I'll reduce the merging target to just 4 segments? e.g., When searching a term, does Lucene needs to visit each segment (disk seek operation) to access the relevant posting list? If not then what's the advantage of merging down segments (besides open files limit). *Was wondering if anyone has tested # of segments against search time performance?* I should add I have ~10 indexes, at a total size of 50GB, and I use mutli-index searcher to search over them (Lucene 3.0.3 - yeah it's old I know). The index is updated every 15min. Gili Nachum.
