Performance Issue

[LieutenantRoger]

We have multiple tickets are discussing the performance issue.

Here, I will create a single ticket to summarize all tickets link here, while closing the invididual tickets, so we are more clear about the issue.

[LieutenantRoger]

The issue list is:

#140

#138

#137

#135

#134

#131

#130

#129

#123

#121

#105

#103

#74

#72

#104

#257

#250

#315