I see a chart labeled Hit Ratio in the ProTop Portal. What's it about?
The “hit ratio” (left axis) is the percentage of block references that were satisfied directly from the buffer pool without needing to fetch data from the disk.
Log2Rec (right axis) is the ratio of logical reads to record reads – if it takes one index read and one data block read to fetch a record, then log2rec = 2.
These metrics are ”per second”.