Hello developers, it seems that I found an issue accidentally.

When do ptrack_get_pagemapset() query, this function will get all relation files and then retrieve each file to construct its page map information.

1. ptrack_filelist_getnext() is to get the next relation file's info, please notice this two lines (just consider only one segment file case)
   ctx->bid.blocknum = 0;
   ctx->relsize = fst.st_size / BLCKSZ;
2. ptrack_get_pagemapset() will do loop to check whether there're this block's update lsn or not, please notice the loop condition:
   /* Stop traversal if there are no more segments */
   if (ctx->bid.blocknum > ctx->relsize) { complete this segment to output, and get next relation file to loop }

Obviously,if (ctx->bid.blocknum > ctx->relsize) should beif (ctx->bid.blocknum + 1 >= ctx->relsize) ?

And another small question: maybe ctx->relsize will be better named blknums?

If I miss some points and this is not an issue, apology for my disturbance.

Regards,
Bird