Dumps information about free space in log part files for the
data node with the node ID
node_id. The dump is written to
the data node out log rather than to the cluster log.
REDO part: 0 HEAD: file: 0 mbyte: 2 TAIL: file: 0 mbyte: 2 total: 256 free: 256 (mb) REDO part: 1 HEAD: file: 0 mbyte: 2 TAIL: file: 0 mbyte: 2 total: 256 free: 256 (mb) REDO part: 2 HEAD: file: 0 mbyte: 2 TAIL: file: 0 mbyte: 2 total: 256 free: 256 (mb) REDO part: 3 HEAD: file: 0 mbyte: 2 TAIL: file: 0 mbyte: 2 total: 256 free: 256 (mb)
Additional Information. Each line of the output has the following format (shown here split across two lines for legibility):
A data node's redo log is divided into four parts; thus,
part_no is always a number between
0 and 3 inclusive. The parts are stored in the data node file
directories with redo log part 0 being stored in
D8, part 1 in
and so on (see
Section 126.96.36.199, “MySQL Cluster Data Node File System Directory Files”).
Within each directory can be found a
DBLQH subdirectory containing
files. The default value for
NoOfFragmentLogFiles is 16. The default
size of each of these files is 16 MB; this can be changed by
start_file_no indicates the number
of the file and
start_pos the point
inside this file in which the redo log starts; for the example
just shown, since
part_no is 0,
this means that the redo log starts at approximately 12 MB
from the end of the file
to the number of the file and
end_pos to the point within that
file where the redo log ends. Thus, in the previous example,
the redo log's end point comes approximately 10 MB from
the end of
total_space shows the total amount
of space reserved for part
of the redo log. This is equal to
NoOfFragmentLogFiles * FragmentLogFileSize;
by default this is 16 times 16 MB, or 256 MB.
free_space shows the amount
remaining. Thus, the amount used is equal to
; in this
example, this is 256 - 254 = 2 MB.
It is not recommended to execute
2398 while a data node restart is in progress.
DUMP 2398 was added in MySQL Cluster NDB
6.3.28 and MySQL Cluster NDB 7.0.9.