  Many Duplicate Bug Report Detection (DBRD) techniques have been proposed in
the research literature. The industry uses some other techniques.
Unfortunately, there is insufficient comparison among them, and it is unclear
how far we have been. This work fills this gap by comparing the aforementioned
techniques. To compare them, we first need a benchmark that can estimate how a
tool would perform if applied in a realistic setting today. Thus, we first
investigated potential biases that affect the fair comparison of the accuracy
of DBRD techniques. Our experiments suggest that data age and issue tracking
system choice cause a significant difference. Based on these findings, we
prepared a new benchmark. We then used it to evaluate DBRD techniques to
estimate better how far we have been. Surprisingly, a simpler technique
outperforms recently proposed sophisticated techniques on most projects in our
benchmark. In addition, we compared the DBRD techniques proposed in research
with those used in Mozilla and VSCode. Surprisingly, we observe that a simple
technique already adopted in practice can achieve comparable results as a
recently proposed research tool. Our study gives reflections on the current
state of DBRD, and we share our insights to benefit future DBRD research.
