fix: Race condition for pouchdb hanging indefinitely when multiple instances are used #8513
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This is a simple repro for a problem discovered in PouchDB 7.3.0. This was originally discovered in RxDB. Discussion here: pubkey/rxdb#3807. ``` 134 passing (2s) 3 pending 1 failing 1) test.memory-adapter.js Race condition initially discovered with PouchDB in-memory-adapter 7.3.0: Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. at listOnTimeout (node:internal/timers:559:17) at processTimers (node:internal/timers:502:7) ```
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I've updated my PR:
Hope this gets included into a future release! 🤞🏼 |
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garethbowen
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Thanks for the test, that's really helpful. I've added a suggestion.
| var adapterName = functionName(leveldown); | ||
| var adapterStore = dbStores.get(adapterName); | ||
| var keys = [...adapterStore.keys()].filter(k => k.includes("-mrview-")); | ||
| var keys = [...adapterStore.keys()].filter(k => k.includes(name)).filter(k => k.includes("-mrview-")); |
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I think there's a small issue here if you have two dbs with the same prefix, for example, "test-db" and "test-db-2". If you close "test-db" the same race condition will occur. I think we can make the matching string more restrictive to avoid these edge cases, eg:
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| var keys = [...adapterStore.keys()].filter(k => k.includes(name)).filter(k => k.includes("-mrview-")); | |
| var viewNamePrefix = PouchDB.prefix + name + "-mrview-"; | |
| var keys = [...adapterStore.keys()].filter(k => k.includes(viewNamePrefix)); |
You'll have to import PouchDB too, and I haven't actually run this code, but I think it'll work.
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Thanks for looking this over! Ran this locally and it seemed to work. Updated the tests and used the code snippet you provided. Just pushed the commit. CI should complete in about 10 minutes to verify.
maximerety
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…ly when multiple instances are used" This reverts commit 24157fc.
CaptainAchab
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Release notes: https://github.com/pouchdb/pouchdb/releases/tag/8.0.0 It includes a fix for our issue with multiple PouchDB instances used concurrently, see: apache/pouchdb#8513. Also note that we are waiting for a clarification about the way dependent databases are handled in PouchDB. This could lead to new changes, see: apache/pouchdb#8574. We still allow compat with versions >= 7.2.2 < 7.3.0 for ease of use alongside previous Tanker SDK versions that required these versions. We ban the 7.3.x versions though since they are affected by the aforementioned bug.
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This is a self-contained repro for a problem discovered in PouchDB 7.3.0 where 2 databases using the
memoryadapter could impact each other and ultimately become non-responsive.This was originally discovered in the RxDB test suite. Discussion here: pubkey/rxdb#3807.