Add a remark about upsert’s race conditions #3910
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Describe this PR
I have been bitten hard by this issue:
This is because I have assumed that Prisma’s upsert behavior would be equivalent to MongoDB’s behavior.
ON DUPLICATE KEY
orON CONFLICT
clause, so the database makes sure that 2 simulataneousupsert
’s on the same document with same unique key are treated sequentially — oneupsert
results in aninsert
, and the other results in anupdate
.SELECT
followed byINSERT
/UPDATE
. If 2 simultaneous upserts are taking place, it could lead to a race condition where both upserts does not see an existing record and both attempts to insert, resulting in a P2002 error.Changes
Document this behavior. This is the remark I wish I saw when I decided to use this method.
What issue does this fix?
prisma/prisma#3242
Any other relevant information
N/A