seromenho / prisma-join-performance

Reproduce prisma error on "JOIN" a big data set

This repo reproduces the error happening when you want to get data from other tables.

Can't reach database server at `localhost`:`5432`

    Please make sure your database server is running at `localhost`:`5432`.

Prisma doesn't do a JOIN when you might think it does. Instead batches smaller chunks queries with the result from the previou one as better explained here: https://youtu.be/RAoXdyI_PH4?t=1059

Conclusions

Prisma fails to get more than ~20k records while using a JOIN works well.

Possible reasons

Not really sure about the reasons but might be:

1. Huge second(third/fourth/so on) query being created after the first one returning 40k id's so the second query to query model B is something like

SELECT  
...  
FROM "B"  
WHERE "aId" IN (....40K ids here)

Doesn't seem it passes the char limit for the query but could be related to the query lenght.

Possible solution

1. Give the user the choice to execute a real join...