()
| 1038 | |
| 1039 | it(class="st">'supports for share (i.e. `SELECT ... LOCK IN SHARE MODE`)', async function() { |
| 1040 | const verifySelectLockInShareMode = async () => { |
| 1041 | const User = this.sequelize.define(class="st">'user', { |
| 1042 | username: DataTypes.STRING, |
| 1043 | awesome: DataTypes.BOOLEAN |
| 1044 | }, { timestamps: false }); |
| 1045 | |
| 1046 | await this.sequelize.sync({ force: true }); |
| 1047 | const { id } = await User.create({ username: class="st">'jan' }); |
| 1048 | |
| 1049 | class="cm">// First, we start a transaction T1 and perform a SELECT with it using the `LOCK.SHARE` mode (setting a shared mode lock on the row). |
| 1050 | class="cm">// This will cause other sessions to be able to read the row but not modify it. |
| 1051 | class="cm">// So, if another transaction tries to update those same rows, it will wait until T1 commits (or rolls back). |
| 1052 | class="cm">// https://dev.mysql.com/doc/refman/5.7/en/innodb-locking-reads.html |
| 1053 | const t1 = await this.sequelize.transaction(); |
| 1054 | await User.findByPk(id, { lock: t1.LOCK.SHARE, transaction: t1 }); |
| 1055 | |
| 1056 | class="cm">// Then we start another transaction T2 and see that it can indeed read the same row. |
| 1057 | const t2 = await this.sequelize.transaction({ isolationLevel: Transaction.ISOLATION_LEVELS.READ_COMMITTED }); |
| 1058 | const t2Jan = await User.findByPk(id, { transaction: t2 }); |
| 1059 | |
| 1060 | class="cm">// Then, we want to see that an attempt to update that row from T2 will be queued until T1 commits. |
| 1061 | const executionOrder = []; |
| 1062 | const [t2AttemptData, t1AttemptData] = await pSettle([ |
| 1063 | (async () => { |
| 1064 | try { |
| 1065 | executionOrder.push(class="st">'Begin attempt to update via T2'); |
| 1066 | await t2Jan.update({ awesome: false }, { transaction: t2 }); |
| 1067 | executionOrder.push(class="st">'Done updating via T2'); |
| 1068 | } catch (error) { |
| 1069 | executionOrder.push(class="st">'Failed to update via T2'); class="cm">// Shouldn't happen |
| 1070 | throw error; |
| 1071 | } |
| 1072 | |
| 1073 | await delay(30); |
| 1074 | |
| 1075 | try { |
| 1076 | executionOrder.push(class="st">'Attempting to commit T2'); |
| 1077 | await t2.commit(); |
| 1078 | executionOrder.push(class="st">'Done committing T2'); |
| 1079 | } catch { |
| 1080 | executionOrder.push(class="st">'Failed to commit T2'); class="cm">// Shouldn't happen |
| 1081 | } |
| 1082 | })(), |
| 1083 | (async () => { |
| 1084 | await delay(100); |
| 1085 | |
| 1086 | try { |
| 1087 | executionOrder.push(class="st">'Begin attempt to read via T1'); |
| 1088 | await User.findAll({ transaction: t1 }); |
| 1089 | executionOrder.push(class="st">'Done reading via T1'); |
| 1090 | } catch (error) { |
| 1091 | executionOrder.push(class="st">'Failed to read via T1'); class="cm">// Shouldn't happen |
| 1092 | throw error; |
| 1093 | } |
| 1094 | |
| 1095 | await delay(150); |
| 1096 | |
| 1097 | try { |
no test coverage detected