>> Derek Zhou <derek(a)shannon-data.com&gt; schrieb am 14.12.2018 um 07:27 in Nachricht

On Thursday, December 13, 2018 05:24:53 PM Derek Zhou wrote: > Howard and others: > > Again on deleting lots of entries. I have 2 experiments: > > 1, in a fresh db insert 10 million entries. let's call this state A. then delete 9 million entries over night. let's call this state B > 2, in a fresh db insert 1 million entries I call this state B' > > In B and B' even the 1 million entries are the same; so from user's perspective B and B' are indistinguishable. However, deleting entries from B is much slower than deleting entries from B', like 10x slower. It seems like deleting speed depends on the peak db size, and how full the db currently is. > > My question is: is this wide a deletion performance gap expected? > Further testing shows that this deletion speed drop only happens in writemap mode. default mode is much better.