Lars Hofhansl created HBASE-10805: ------------------------------------- Summary: Speed up KeyValueHeap.next() a bit Key: HBASE-10805 URL: https://issues.apache.org/jira/browse/HBASE-10805 Project: HBase Issue Type: Bug Reporter: Lars Hofhansl Fix For: 0.99.0, 0.94.19, 0.98.2, 0.96.3
See discussion on HBASE-9969. This was brought up by [~mcorgan]. Even though I didn't believe him first. {code} KeyValueScanner topScanner = this.heap.peek(); if (topScanner == null || this.comparator.compare(kvNext, topScanner.peek()) >= 0) { this.heap.add(this.current); this.current = pollRealKV(); } {code} We already have the invariant everywhere this.current always has a real KV polled. So adding current back to the heap followed by pollRealKV() is a no-op if this.current is the only scanner anyway. This can be changed to: {code} ... if (topScanner != null && this.comparator.compare(kvNext, topScanner.peek()) >= 0) { ... {code} With 20m rows, 5 cols each, everything in the cache, fully compacted - i.e. one HFile per store, a scan that filters everything at the server through all 100m KVs takes 15.1s without the change and 13.3s with it, so a 12% improvement. -- This message was sent by Atlassian JIRA (v6.2#6252)