Update docs to clarify issues raised in #14272 (#14318)

- example config is not supposed to be copied
- 'persistable-channel' uses a leveldb internally
- '*CONN_STR' overrides queue DIR

custom/conf/app.example.ini

@@ -1,6 +1,8 @@
 ; This file lists the default values used by Gitea
 ; Copy required sections to your own app.ini (default is custom/conf/app.ini)
 ; and modify as needed.
+; Do not copy the whole file as-is, as it contains some invalid sections for illustrative purposes.
+; If you don't know what a setting is you should not set it.
 
 ; see https://docs.gitea.io/en-us/config-cheat-sheet/ for additional documentation.
 
@@ -451,10 +453,13 @@ ISSUE_INDEXER_NAME = gitea_issues
 ISSUE_INDEXER_PATH = indexers/issues.bleve
 ; Issue indexer queue, currently support: channel, levelqueue or redis, default is levelqueue
 ISSUE_INDEXER_QUEUE_TYPE = levelqueue
-; When ISSUE_INDEXER_QUEUE_TYPE is levelqueue, this will be the queue will be saved path,
+; When ISSUE_INDEXER_QUEUE_TYPE is levelqueue, this will be the path where the queue will be saved.
+; This can be overriden by `ISSUE_INDEXER_QUEUE_CONN_STR`.
 ; default is indexers/issues.queue
 ISSUE_INDEXER_QUEUE_DIR = indexers/issues.queue
 ; When `ISSUE_INDEXER_QUEUE_TYPE` is `redis`, this will store the redis connection string.
+; When `ISSUE_INDEXER_QUEUE_TYPE` is `levelqueue`, this is a directory or additional options of
+; the form `leveldb://path/to/db?option=value&....`, and overrides `ISSUE_INDEXER_QUEUE_DIR`.
 ISSUE_INDEXER_QUEUE_CONN_STR = "addrs=127.0.0.1:6379 db=0"
 ; Batch queue number, default is 20
 ISSUE_INDEXER_QUEUE_BATCH_NUMBER = 20
@@ -494,6 +499,8 @@ LENGTH = 20
 ; Batch size to send for batched queues
 BATCH_LENGTH = 20
 ; Connection string for redis queues this will store the redis connection string.
+; When `TYPE` is `persistable-channel`, this provides a directory for the underlying leveldb
+; or additional options of the form `leveldb://path/to/db?option=value&....`, and will override `DATADIR`.
 CONN_STR = "addrs=127.0.0.1:6379 db=0"
 ; Provides the suffix of the default redis/disk queue name - specific queues can be overriden within in their [queue.name] sections.
 QUEUE_NAME = "_queue"

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -331,8 +331,8 @@ relation to port exhaustion.
 - `ISSUE_INDEXER_PATH`: **indexers/issues.bleve**: Index file used for issue search; available when ISSUE_INDEXER_TYPE is bleve and elasticsearch.
 - The next 4 configuration values are deprecated and should be set in `queue.issue_indexer` however are kept for backwards compatibility:
 - `ISSUE_INDEXER_QUEUE_TYPE`: **levelqueue**: Issue indexer queue, currently supports:`channel`, `levelqueue`, `redis`.
-- `ISSUE_INDEXER_QUEUE_DIR`: **indexers/issues.queue**: When `ISSUE_INDEXER_QUEUE_TYPE` is `levelqueue`, this will be the queue will be saved path.
-- `ISSUE_INDEXER_QUEUE_CONN_STR`: **addrs=127.0.0.1:6379 db=0**: When `ISSUE_INDEXER_QUEUE_TYPE` is `redis`, this will store the redis connection string.
+- `ISSUE_INDEXER_QUEUE_DIR`: **indexers/issues.queue**: When `ISSUE_INDEXER_QUEUE_TYPE` is `levelqueue`, this will be the path where the queue will be saved.
+- `ISSUE_INDEXER_QUEUE_CONN_STR`: **addrs=127.0.0.1:6379 db=0**: When `ISSUE_INDEXER_QUEUE_TYPE` is `redis`, this will store the redis connection string. When `ISSUE_INDEXER_QUEUE_TYPE` is `levelqueue`, this is a directory or additional options of the form `leveldb://path/to/db?option=value&....`, and overrides `ISSUE_INDEXER_QUEUE_DIR`.
 - `ISSUE_INDEXER_QUEUE_BATCH_NUMBER`: **20**: Batch queue number.
 
 - `REPO_INDEXER_ENABLED`: **false**: Enables code search (uses a lot of disk space, about 6 times more than the repository size).
@@ -350,11 +350,11 @@ relation to port exhaustion.
 
 ## Queue (`queue` and `queue.*`)
 
-- `TYPE`: **persistable-channel**: General queue type, currently support: `persistable-channel`, `channel`, `level`, `redis`, `dummy`
+- `TYPE`: **persistable-channel**: General queue type, currently support: `persistable-channel` (uses a LevelDB internally), `channel`, `level`, `redis`, `dummy`
 - `DATADIR`: **queues/**: Base DataDir for storing persistent and level queues. `DATADIR` for individual queues can be set in `queue.name` sections but will default to `DATADIR/`**`name`**.
 - `LENGTH`: **20**: Maximal queue size before channel queues block
 - `BATCH_LENGTH`: **20**: Batch data before passing to the handler
-- `CONN_STR`: **redis://127.0.0.1:6379/0**: Connection string for the redis queue type. Options can be set using query params. Similarly LevelDB options can also be set using: **leveldb://relative/path?option=value** or **leveldb:///absolute/path?option=value**
+- `CONN_STR`: **redis://127.0.0.1:6379/0**: Connection string for the redis queue type. Options can be set using query params. Similarly LevelDB options can also be set using: **leveldb://relative/path?option=value** or **leveldb:///absolute/path?option=value**, and will override `DATADIR`
 - `QUEUE_NAME`: **_queue**: The suffix for default redis and disk queue name. Individual queues will default to **`name`**`QUEUE_NAME` but can be overriden in the specific `queue.name` section.
 - `SET_NAME`: **_unique**: The suffix that will be added to the default redis and disk queue `set` name for unique queues. Individual queues will default to
  **`name`**`QUEUE_NAME`_`SET_NAME`_ but can be overridden in the specific `queue.name` section.