ArchiveIndex has a member: std::vector runs
The last element of this vector is the run being generated.
T1: Archiver Thread
T2: Writer Thread
// Run 1
T1: assemb.start() //get block
T1: assemb.add(lr)... assemb.add(lr)... assemb.add(lr)...
T1: assemb.finish() ----> newBlock()
// Run 2
T1: assemb.start() //get block
T1: assemb.add(lr)... assemb.add(lr)... assemb.add(lr)...
T2: closeCurrentRun() ----> finishRun() //inserts empty run element to the back of runs (for the new run)
newBlock() inserts an empty block in the run runs.back().
A new run is only inserted in the runs vector after the Writer Thread finished writing the current run to disk. Therefore, the Archiver Thread may start processing log records pertaining to a new run and inserting then to the element runs.back() which refers to the old run (because it was not written to disk yet).
caetanosauer
commented
9 years ago
ArchiveIndex has a member: std::vector runs
The last element of this vector is the run being generated.
T1: Archiver Thread T2: Writer Thread
newBlock() inserts an empty block in the run runs.back().
A new run is only inserted in the runs vector after the Writer Thread finished writing the current run to disk. Therefore, the Archiver Thread may start processing log records pertaining to a new run and inserting then to the element runs.back() which refers to the old run (because it was not written to disk yet).