Restore particular tables

[sanikolaev]

It would be great to be able to restore a particular table. IMPORT can be automated for that, e.g.:

root@bb5278967f62:/# mysql -P9306 -h0 -e "insert into t(f) values('abc'); flush ramchunk t;"
root@bb5278967f62:/# mysql -P9306 -h0 -e "insert into t2(f) values('abc'); flush ramchunk t2;"
root@bb5278967f62:/# mysql -P9306 -h0 -e "backup table t to /tmp/"
+----------------------------+
| Path                       |
+----------------------------+
| /tmp/backup-20230222140126 |
+----------------------------+
root@bb5278967f62:/# mysql -P9306 -h0 -e "drop table t"
root@bb5278967f62:/# mysql -P9306 -h0 -e "import table t from '/tmp/backup-20230222140126/data/t/t'"
root@bb5278967f62:/# mysql -P9306 -h0 -e "select * from t"
+---------------------+------+
| id                  | f    |
+---------------------+------+
| 4901936465623121921 | abc  |
+---------------------+------+

UPDATE Jan 19th 2024

For the sake of data safety and high availabiliy it makes sense to:

• first off import a table into a temporary table (may take time since we copy the files here)
• then if all is ok, truncate the table being restored
• then move chunks from the temporary table to the new one (should be instant as the chunks are in the same data dir and we move them). Use ATTACH for that (available for RT since https://github.com/manticoresoftware/manticoresearch/commit/af5812cc0affbb74f31d6f9d4f0ea34f6ec64a0f)

This should protect from losing the table in the middle of importing a table due to an instance shutdown or smth else.

Let's also add support for wildcards in --tables, so

• --restore --tables=tbl1,tbl2 restores tbl1 and tbl2
• --restore --tables=tbl* restores all tbl*. Let's support wildcards % and *

We'll also need to cover the new functionality with CLT tests.