oc_filecache table with inconsistent entries (size = -1)

From https://github.com/nextcloud/server/issues/31283 I executed the query

`SELECT DISTINCT f.path, f.size, f.parent FROM oc_filecache AS f INNER JOIN oc_mounts AS m ON m.storage_id = f.storage WHERE size <
0 AND parent > 1 LIMIT 20;

+--------------------------------------------+------+---------+
| path | size | parent |
+--------------------------------------------+------+---------+
| appdata_ocx89t9we96j/preview/0 | -1 | 1057528 |
| appdata_ocx89t9we96j/preview/0/0 | -1 | 1057632 |
| appdata_ocx89t9we96j/preview/0/0/1 | -1 | 1059331 |
| appdata_ocx89t9we96j/preview/0/0/1/6 | -1 | 1065977 |
| appdata_ocx89t9we96j/preview/0/0/1/6/d | -1 | 1065978 |
| appdata_ocx89t9we96j/preview/0/0/1/6/d/1 | -1 | 1065979 |
| appdata_ocx89t9we96j/preview/0/0/1/6/d/1/5 | -1 | 1065980 |
| appdata_ocx89t9we96j/preview/0/0/4 | -1 | 1059331 |
| appdata_ocx89t9we96j/preview/0/0/4/b | -1 | 1080928 |
| appdata_ocx89t9we96j/preview/0/0/4/b/2 | -1 | 1080929 |
| appdata_ocx89t9we96j/preview/0/0/4/b/9 | -1 | 1080929 |
| appdata_ocx89t9we96j/preview/0/0/5 | -1 | 1059331 |
| appdata_ocx89t9we96j/preview/0/0/7 | -1 | 1059331 |
| appdata_ocx89t9we96j/preview/0/0/7/d | -1 | 1063945 |
| appdata_ocx89t9we96j/preview/0/0/7/d/c | -1 | 1063946 |
| appdata_ocx89t9we96j/preview/0/0/7/d/c/c | -1 | 1063947 |
| appdata_ocx89t9we96j/preview/0/0/7/d/c/c/8 | -1 | 1063948 |
| appdata_ocx89t9we96j/preview/0/0/8 | -1 | 1059331 |
| appdata_ocx89t9we96j/preview/0/0/8/1 | -1 | 1074694 |
| appdata_ocx89t9we96j/preview/0/0/8/1/2 | -1 | 1079351 |
+--------------------------------------------+------+---------+
`

Is it true, that all entries with path appdata_/preview/ and size -1 is an inconsistent entry and should be deleted?

If it is true, can you create a function in the previewgenerator which cleans it up automatically or manual with an occ command?

Start by reviewing the previewgenerator code and the reported oc_filecache query, then trace any existing occ command entry points. Determine whether the appdata_/preview/ rows with size -1 are invalid and define a safe cleanup path. Done means the behavior is confirmed and an automatic or manual cleanup option is clearly specified.