Hi, The regex group capture for matching the TO database is missing i…

…n case the table names are enclosed in a "`". This further leads to wrong restore of materialized views(the TO still point to default database!).

Restore command used:
clickhouse-backup restore_remote --rm -m praveen:default <backup-name>

For example:- If we run the following restore command, the resulting materialized view will be the following.

CREATE MATERIALIZED VIEW praveen.`32da477b_0eb9_4aa6_bcbb_7f511649861e_v0_5_min_mv_shard` TO default.`32da477b_0eb9_4aa6_bcbb_7f511649861e_v0_5_min_mv_inner_shard`
(

    `__created_at` AggregateFunction(max,
 DateTime),

    `__occurred_at` DateTime,

    `environment_id` UUID,

    `aggregation` String,

    `value` AggregateFunction(sum,
 Float64)
) AS
SELECT
    maxState(__created_at) AS __created_at,

    toStartOfFiveMinute(__occurred_at) AS __occurred_at,

    environment_id,

    aggregation,

    sumState(value) AS value
FROM praveen.`32da477b_0eb9_4aa6_bcbb_7f511649861e_v0_5_min_shard`
GROUP BY
    environment_id,

    aggregation,

    __occurred_at
ORDER BY
    environment_id ASC,

    aggregation ASC,

    __occurred_at ASC;

The expected one:-

CREATE MATERIALIZED VIEW praveen.`32da477b_0eb9_4aa6_bcbb_7f511649861e_v0_5_min_mv_shard` TO praveen.`32da477b_0eb9_4aa6_bcbb_7f511649861e_v0_5_min_mv_inner_shard`
(

    `__created_at` AggregateFunction(max,
 DateTime),

    `__occurred_at` DateTime,

    `environment_id` UUID,

    `aggregation` String,

    `value` AggregateFunction(sum,
 Float64)
) AS
SELECT
    maxState(__created_at) AS __created_at,

    toStartOfFiveMinute(__occurred_at) AS __occurred_at,

    environment_id,

    aggregation,

    sumState(value) AS value
FROM praveen.`32da477b_0eb9_4aa6_bcbb_7f511649861e_v0_5_min_shard`
GROUP BY
    environment_id,

    aggregation,

    __occurred_at
ORDER BY
    environment_id ASC,

    aggregation ASC,

    __occurred_at ASC;

pkg/backup/table_pattern.go

@@ -295,7 +295,7 @@ func (b *Backuper) enrichTablePatternsByInnerDependencies(metadataPath string, t
 	return tablePatterns, nil
 }
 
-var queryRE = regexp.MustCompile(`(?m)^(CREATE|ATTACH) (TABLE|VIEW|LIVE VIEW|MATERIALIZED VIEW|DICTIONARY|FUNCTION) (\x60?)([^\s\x60.]*)(\x60?)\.([^\s\x60.]*)(?:( UUID '[^']+'))?(?:( TO )(\x60?)([^\s\x60.]*)(\x60?)(\.))?(?:(.+FROM )(\x60?)([^\s\x60.]*)(\x60?)(\.))?`)
+var queryRE = regexp.MustCompile(`(?m)^(CREATE|ATTACH) (TABLE|VIEW|LIVE VIEW|MATERIALIZED VIEW|DICTIONARY|FUNCTION) (\x60?)([^\s\x60.]*)(\x60?)\.\x60?([^\s\x60.]*)\x60?( UUID '[^']+')?(?:( TO )(\x60?)([^\s\x60.]*)(\x60?)(\.))?(?:(.+FROM )(\x60?)([^\s\x60.]*)(\x60?)(\.))?`)
 var createOrAttachRE = regexp.MustCompile(`(?m)^(CREATE|ATTACH)`)
 var uuidRE = regexp.MustCompile(`UUID '([a-f\d\-]+)'`)