[performance improvement] remove duplicate LoadShardList call

[zhjwpku]

LoadShardList is called twice, which is not neccessary, and there is no need to
sort the shard placement list since we only want to know the list length.

[codecov]

Codecov Report

Merging #7380 (8e49fc5) into main (1d55deb) will increase coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7380      +/-   ##
==========================================
+ Coverage   89.60%   89.62%   +0.01%     
==========================================
  Files         280      280              
  Lines       60304    60302       -2     
  Branches     7505     7505              
==========================================
+ Hits        54036    54043       +7     
+ Misses       4114     4109       -5     
+ Partials     2154     2150       -4     

[JelteF]

Thanks for this. These indeed look like clear improvements. Out of curiosity was the perf impact of these big enough for them to show up in a profile? Or did you simply find them when looking at the code?

[zhjwpku]

Thanks for this. These indeed look like clear improvements. Out of curiosity was the perf impact of these big enough for them to show up in a profile? Or did you simply find them when looking at the code?

Just by looking the code, no perf ;(