Solved: SequelizeDatabaseError: Deadlock found when trying to get lock; try restarting transaction
Sequelize with MySql can throw Deadlock found when trying to get lock.
SequelizeDatabaseError: Deadlock found when trying to get lock; try restarting transaction\n at Query.formatError (/usr/local/xxx/node_modules/sequelize/lib/dialects/mysql/query.js:247:16)\n at Query.handler [as onResult] (/usr/local/xxx/node_modules/sequelize/lib/dialects/mysql/query.js:68:23)\n at Query.execute (/usr/local/xxx/node_modules/mysql2/lib/commands/command.js:30:14)\n at Connection.handlePacket (/usr/local/xxx/node_modules/mysql2/lib/connection.js:408:32)\n at PacketParser.Connection.packetParser.p [as onPacket] (/usr/local/xxx/node_modules/mysql2/lib/connection.js:70:12)\n at PacketParser.executeStart (/usr/local/xxx/node_modules/mysql2/lib/packet_parser.js:75:16)\n at TLSSocket.secureSocket.on.data (/usr/local/xxx/node_modules/mysql2/lib/connection.js:328:25)\n at TLSSocket.emit (events.js:198:13)\n at addChunk (_stream_readable.js:288:12)\n at readableAddChunk (_stream_readable.js:269:11)\n at TLSSocket.Readable.push (_stream_readable.js:224:10)\n at TLSWrap.onStreamRead [as onread] (internal/stream_base_commons.js:94:17)
One of the reasons such error could occur is, usage of FOR UPDATE in MySql select query. MySQL locks range-type if where condition in FOR UPDATE is not UNIQUE keys.
Add a unique key constraint to all columns which are in where condition of SELECT query where FOR UPDATE is used