Thank you.
The database was corrupted (usually an abrupt power-off / interruption can cause this).
Apr 26, 2020 00:02:34.915 [0x7ff5d8ea3700] INFO - Plex Media Server v1.19.2.2702-776106bc6 - Synology DS216+II x86_64 - build: linux-x86_64 synology - GMT 01:00
Apr 26, 2020 00:02:34.915 [0x7ff5d8ea3700] INFO - Linux version: DSM 6.2.2.24922-4, language: en-US
Apr 26, 2020 00:02:34.915 [0x7ff5d8ea3700] INFO - Processor Intel(R) Celeron(R) CPU N3060 @ 1.60GHz
Apr 26, 2020 00:02:34.915 [0x7ff5d8ea3700] INFO - /var/packages/Plex Media Server/target/Plex Media Server
Apr 26, 2020 00:02:34.911 [0x7ff5e2cd6740] DEBUG - BPQ: [Idle] -> [Starting]
Apr 26, 2020 00:02:34.912 [0x7ff5e2cd6740] DEBUG - FeatureManager: Using cached data for features list
Apr 26, 2020 00:02:34.913 [0x7ff5e2cd6740] DEBUG - Opening 20 database sessions to library (com.plexapp.plugins.library), SQLite 3.26.0, threadsafe=1
Apr 26, 2020 00:02:34.917 [0x7ff5e2cd6740] INFO - SQLITE3:(nil), 283, recovered 970 frames from WAL file /volume1/Plex/Library/Application Support/Plex Media Server/Plug-in Support/Databases/com.plexapp.plugins.library.db-wal
Apr 26, 2020 00:02:35.096 [0x7ff5e2cd6740] DEBUG - Running migrations. (EPG 0)
Apr 26, 2020 00:02:35.158 [0x7ff5e2cd6740] ERROR - SQLITE3:(nil), 11, database corruption at line 85694 of [bf8c1b2b7a]
Apr 26, 2020 00:02:35.158 [0x7ff5e2cd6740] ERROR - SQLITE3:(nil), 11, statement aborts at 4: [select max(max(metadata_items.changed_at),max(metadata_items.resources_changed_at)) from metadata_items] database disk image is malformed
Apr 26, 2020 00:02:35.158 [0x7ff5e2cd6740] ERROR - Database corruption: sqlite3_statement_backend::loadOne: database disk image is malformed
Apr 26, 2020 00:02:35.159 [0x7ff5e2cd6740] ERROR - Error: Unable to set up server: sqlite3_statement_backend::loadOne: database disk image is malformed (N4soci10soci_errorE)
Here is the procedure to repair it.
