table function that shows fuse table history and basic statistics

[dantengsky]

introduce table function fuse_history, which shows

• fuse table history
• basic statistics for each snapshot

sth like this:

> select * from fuse_history('default', 'test');
+----------------------------------+----------------------------------+---------------+-------------+-----------+--------------------+------------------+
| snapshot_id                      | prev_snapshot_id                 | segment_count | block_count | row_count | uncompressed_bytes | compressed_bytes |
+----------------------------------+----------------------------------+---------------+-------------+-----------+--------------------+------------------+
| b5c164e8a1be4a9588c399eed66e1a69 | 6d3c75712c4f45c3b78345b08dc68da2 |            xx |          xx |       xxx |                xxx |             xxxx |
| 6d3c75712c4f45c3b78345b08dc68da2 | 495a906683fe4bdda2549420a9dc2fc4 |            xx |          xx |   xxxxxxxx|            xxxxxxx |          xxxxxxx |
| 495a906683fe4bdda2549420a9dc2fc4 | eaedc47499d041779e6eaf774c650dca |            xx |          xx |    xxxxxxx|             xxxxxx |           xxxxxx |
| eaedc47499d041779e6eaf774c650dca | 13f6d7099f36453da4c983337810075c |            xx |          xx |      xxxxx|               xxxx |            xxxxx |
| 13f6d7099f36453da4c983337810075c | 1a5d74d4a2a94fc48b997089657232b0 |             x |           x |         x |                 xx |              xxx |
| 1a5d74d4a2a94fc48b997089657232b0 | 419d90b7af854185a2e4f84eeae06a3a |             x |           x |         x |                 xx |              xxx |
| 419d90b7af854185a2e4f84eeae06a3a | NULL                             |             x |           x |         x |                  x |              xxx |
+----------------------------------+----------------------------------+---------------+-------------+-----------+--------------------+------------------+

> select compressed_bytes/block_count as bytes_per_block from fuse_hist('default', 'test') where snapshot_id = 'xxx';

+--------------------+
| bytes_per_block      |
+--------------------+
| 197846.34782608695 |
+--------------------+