Database files
PostgreSQL WAL position difference
Subtract WAL LSNs exactly and show segment-relative positions.
Your inputs
Start with an exampleYour result
Example resultAa — A small example of your colors.
How it works
Interpret each LSN as two 32-bit hex halves. Subtract right − left with 64-bit integer precision, then divide by segment size.
0/10 minus 0/0 is 16 bytes because the low half is hexadecimal.
Limits
A byte-position difference, not elapsed replication lag or a health estimate. Segment size must match the cluster and be a power of two MiB. Timelines and WAL filenames are not inferred.