Comment 1 for bug 1579987

Set the fc_limit=20000, and then block the node ("flush tables with read lock").
The queue will eventually reach the limit (which is actually ~34800), but
before that it will reach the size of the receive queue (which is set upon
startup, and on a 256MB machine will hold 32K entries). If you then
"unlock tables", this will hit an assert in the code.

There is a bug in the fifo queue implementation (galerautils/src/gu_fifo.c)
that if the circular buffer has wrapped (so that -->tail ... head-->)
and if head and tail are in the same row, when head reaches
the end of the row,it will free() the row, thus erasing part of the entries.

The upper_limit and lower_limit can also be set to be higher than the size
of the receive queue which doesn't seem to be the behavior we want.