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# 7.1.1. `grndb`

## 7.1.1.1. Summary

Added in version 4.0.9.

`grndb` manages a Groonga database.

Here are features:

> - Checks whether database is broken or not.

> - Recovers broken database automatically if the database is recoverable.

## 7.1.1.2. Syntax

`grndb` requires command and database path:

    grndb COMMAND [OPTIONS] DATABASE_PATH

Here are available commands:

> - `check` - Checks whether database is broken or not.

> - `recover` - Recovers database.

## 7.1.1.3. Usage

Here is an example to check the database at `/var/lib/groonga/db/db`:

    % grndb check /var/lib/groonga/db/db

Here is an example to recover the database at `/var/lib/groonga/db/db`:

    % grndb recover /var/lib/groonga/db/db

## 7.1.1.4. Commands

This section describes available commands.

### 7.1.1.4.1. `check`

It checks an existing Groonga database. If the database is broken, `grndb` reports reasons and exits with non-`0` exit status.

Note

You must not use this command for opened database. If the database is opened, this command may report wrong result.

`check` has some options.

#### 7.1.1.4.1.1. `--target`

Added in version 5.1.2.

It specifies a check target object.

If your database is large and you know an unreliable object, this option will help you. `check` need more time for large database. You can reduce check time by `--target` option to reduce check target.

The check target is checked recursive. Because related objects of unreliable object will be unreliable.

If the check target is a table, all columns of the table are also checked recursive.

If the check target is a table and its key type is another table, the another table is also checked recursive.

If the check target is a column and its value type is a table, the table is also checked recursive.

If the check target is an index column, the table specified as value type and all sources are also checked recursive.

Here is an example that checks only `Entries` table and its columns:

    % grndb check --target Entries /var/lib/groonga/db/db

Here is an example that checks only `Entries.name` column:

    % grndb check --target Entries.name /var/lib/groonga/db/db

#### 7.1.1.4.1.2. `--log-level`

Added in version 7.0.4.

It specifies a log level of `grndb` log.

Here is an example that specifies `--log-level` option:

    % grndb check --log-level info --log-path /var/log/groonga/grndb.log /var/lib/groonga/db/db

See log_level to know about supported log level.

#### 7.1.1.4.1.3. `--log-path`

Added in version 7.0.4.

It specifies a path of `grndb` log.

Here is an example that specifies `--log-path` option:

    % grndb check --log-path /var/log/groonga/grndb.log /var/lib/groonga/db/db

#### 7.1.1.4.1.4. `--log-flags`

Added in version 9.0.3.

It specifies a logged content in `grndb` log by flags. The default value of `--log-flags` is `time|message`. It means that timestamp and log messages are logged into `grndb` log.

Here is an example that specifies `--log-flags` option:

    % grndb check --log-path /var/log/groonga/grndb.log --log-flags "time|pid|message" /var/lib/groonga/db/db

See groonga executable file to know about supported log flags.

#### 7.1.1.4.1.5. `--since`

Added in version 9.0.4.

It specifies the object’s modified time which should be checked. If object’s modified time is newer than the specified time, these objects are checked by `grndb`. You can specify the modified time as ISO 8601 format or `-NUNIT` format such as -3days or -2.5weeks format.

Here is an example that specifies `--since` option in ISO 8601 format:

    % grmdb check --since=2019-06-24T18:16:22 /var/lib/groonga/db/db

In above example, the objects which are modified after `2019-06-24T18:16:22` are checked.

Here is an example that specifies `--since` option in `-NUNIT` format:

    % grmdb check --since=-7d /var/lib/groonga/db/db

In above example, the objects which are modified in recent 7 days are checked.

`-NUNIT` accepts the following suffix as a unit.

Supported suffix | Description
--- | ---
`s`, `sec`, `secs`, `second`, `seconds` | Specify recent N seconds. For example, `--since=-100s` means within recent 100 seconds should be checked.
`m`, `min`, `mins`, `minute`, `minutes` | Specify recent N minutes. For example, `--since=-10m` means within recent 10 minutes should be checked.
`h`, `hour`, `hours` | Specify recent N hours. For example, `--since=-10h` means within recent 10 hours should be checked.
`d`, `day`, `days` | Specify recent N days. For example, `--since=-10d` means within recent 10 days should be checked.
`w`, `week`, `weeks` | Specify recent N weeks. For example, `--since=-10w` means within recent 10 weeks should be checked.
`month`, `months` | Specify recent N months. For example, `--since=-10month` means within recent 10 months should be checked.
`year`, `years` | Specify recent N years. For example, `--since=-1year` means within recent 1 year should be checked.

### 7.1.1.4.2. `recover`

It recovers an existing broken Groonga database.

If the database is not broken, `grndb` does nothing and exits with `0` exit status.

If the database is broken and one or more index columns are only broken, `grndb` recovers these index columns and exists with `0` exit status. It may take a long time for large indexed data.

If the database is broken and tables or data columns are broken, `grndb` reports broken reasons and exits with non-`0` exit status. You can know whether the database is recoverable or not by `check` command.

Note

You must not use this command for opened database. If the database is opened, this command may break the database.

`recover` has some options.

#### 7.1.1.4.2.1. `--force-truncate`

Added in version 7.0.4.

It forces to truncate a corrupted database object.

Here is an example that specifies `--force-truncate` option:

    % grndb recover --force-truncate --log-level info --log-path /var/log/groonga/grndb.log /var/lib/groonga/db/db

When this option is specified, `grndb` does the followings:

- check whether there is a corrupted database object (table, column, indexes)

- truncate a corrupted database object (table, column, indexes)

- remove incremental files with .00N suffix which is created when large amount of data is loaded

`--force-truncate` option is destructive one. Even though lock is still remained, `grndb` truncates a targeted corrupted database object.

After `grndb recover` command has finished, you need to load data against truncated tables or columns to recreate database.

Note

You must use this option only when necessary. It means that you use it when there is a mismatch between database meta information and database object files which exists actually. This options should be used when there is no other way to recover database.

#### 7.1.1.4.2.2. `--force-lock-clear`

Added in version 7.1.1.

It forces to clear lock of database, table and data column. It doesn’t clear lock of index column. If index column has lock, the index column is recreated instead of clearing lock.

Normally, you should truncate and load data again instead of just clearing lock. Because objects that have lock may be broken. This option is provided only for users who know the risk that “the database may be broken but I want to keep using it”.

Here is an example that specifies `--force-lock-clear` option:

    % grndb recover --force-lock-clear --log-level info --log-path /var/log/groonga/grndb.log /var/lib/groonga/db/db

When this option is specified, `grndb` does the followings:

- check whether there are database, table or data column that have lock

- clear lock of these objects

Note

You must use this option only when necessary. Because your database may not be recovered. The database that has objects that have lock may be broken or not be broken. You can keep using the database but Groonga may crash if the database is broken.

#### 7.1.1.4.2.3. `--log-level`

Added in version 7.0.4.

It specifies a log level of `grndb` log.

Here is an example that specifies `--log-level` option:

    % grndb recover --log-level info --log-path /var/log/groonga/grndb.log /var/lib/groonga/db/db

See log_level to know about supported log level.

#### 7.1.1.4.2.4. `--log-path`

Added in version 7.0.4.

It specifies a path of `grndb` log.

Here is an example that specifies `--log-path` option:

    % grndb recover --log-path /var/log/groonga/grndb.log /var/lib/groonga/db/db

#### 7.1.1.4.2.5. `--log-flags`

Added in version 9.0.2.

It specifies a logged content in `grndb` log by flags. The default value of `--log-flags` is `time|message`. It means that timestamp and log messages are logged into `grndb` log.

Here is an example that specifies `--log-flags` option:

    % grndb check --log-path /var/log/groonga/grndb.log --log-flags "time|pid|message" /var/lib/groonga/db/db

See groonga executable file to know about supported log flags.