How a transaction is implemented as a queue hang

[liangzhuang327]

Generally speaking, the above requirements mean that any transaction which has an overlapping scope with a read/write transaction and which was created after that read/write transaction, can’t run in parallel with that read/write transaction.（Mentioned in W3C）

And my question is :
How does indexedDB do to suspend the remaining transactions when multiple read/write transactions are opened at the same time? Is it done with the browser's Event Loop?

[inexorabletash]

The transaction processing model is somewhat underspecified (and has been the case since the initial IDB spec); the relevant text is in https://w3c.github.io/IndexedDB/#transaction-scheduling and https://w3c.github.io/IndexedDB/#transaction-lifecycle which rather informally defines the preconditions for a transaction to start.

Ideally, the spec would define transaction scheduling e.g. as a parallel queue. The steps are not run synchronously with any agent's (document's/worker's) event queue.

PRs that firm up transaction behavior here would be welcome.