That 52% reduction is similar to the 57% reduction from my test above, lines 2 and 3.
I’m no longer testing line 1 (dblist) recreate, but substituted dbrecr with normal cache.
This allows comparisions betwen the dbrecr and the cache improvements separately.
Combined, of course, is the fastest. Below I switched to testing my typical backup, so
dlist count is higher (about 60), blocksize is 100 KB, and block count is about 256000.
Missing 0 dindex
Processing indexlist volume 214 of 214
Recreate completed, verifying the database consistency
seconds dbrecr dblist cache
409 0 0 0
286 0 0 1
355 1 0 0
277 1 0 1
That’s about a 32% reduction with both enhancements.
Less than the high-block improvement (as you predict).