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I was wondering what the major changes between psycopg2 and psycopg3 were. Found a post from the maintainer here: https://www.varrazzo.com/blog/2020/03/06/think

I was wondering what the major changes between psycopg2 and psycopg3 were. Found a post from the maintainer here: https://www.varrazzo.com/blog/2020/03/06/thinking-psycopg3/ https://www.varrazzo.com/blog/2020/03/06/thinking-psycopg3/ Main takeaways: - Asyncio from the ground up - Uses PQexecParams to do database-side escaping and interpolation - ContextManager and transaction api improvements for - Python only fallback if the C extension fails to build

whoknowswhat11 5y ago
YES to this last!! Musl cross deploy can be annoying otherwise - any tips on building Alpine Linux ?
odiroot 5y ago
> - Asyncio from the ground up > - Python only fallback if the C extension fails to build These two are really big! The former, for first-party async support, making it much easier to use with async frameworks. The latter would make it much easier to ship in containers. I assume it's still better use the C version, for performance reasons.
Waterluvian 5y ago
That last one is great if it’s hidden behind a flag and some loud messages saying “failed to build, consider using —-python-only with performance limitation.” Otherwise it’s going to be a source of mysterious performance issues with a single error message hidden somewhere in your CI or other logs.
- acdha 5y ago
  I'm a bit mixed on a flag because C library dependencies are a fair support burden and an awful lot of people do not have workloads where a pure Python implementation is a significant performance issue because it's lost in the actual work done by the database. I'd agree with something like a warning on first load or maybe something like an optional package so you could pin `psycopg3[cext]` if you want to guarantee the extension installed.
- dvarrazzo 5y ago
  There is a mechanism to ensure that there is no unexpected regression. Exposing the PSYCOPG_IMPL env var a program can make sure to obtain a specific implementation and import fails if it's not available. https://www.psycopg.org/psycopg3/docs/api/pq.html https://www.psycopg.org/psycopg3/docs/api/pq.html

whoknowswhat11 5y ago

YES to this last!! Musl cross deploy can be annoying otherwise - any tips on building Alpine Linux ?

odiroot 5y ago

> - Asyncio from the ground up > - Python only fallback if the C extension fails to build These two are really big! The former, for first-party async support, making it much easier to use with async frameworks. The latter would make it much easier to ship in containers. I assume it's still better use the C version, for performance reasons.

Waterluvian 5y ago

That last one is great if it’s hidden behind a flag and some loud messages saying “failed to build, consider using —-python-only with performance limitation.” Otherwise it’s going to be a source of mysterious performance issues with a single error message hidden somewhere in your CI or other logs.

acdha 5y ago
I'm a bit mixed on a flag because C library dependencies are a fair support burden and an awful lot of people do not have workloads where a pure Python implementation is a significant performance issue because it's lost in the actual work done by the database. I'd agree with something like a warning on first load or maybe something like an optional package so you could pin `psycopg3[cext]` if you want to guarantee the extension installed.
dvarrazzo 5y ago
There is a mechanism to ensure that there is no unexpected regression. Exposing the PSYCOPG_IMPL env var a program can make sure to obtain a specific implementation and import fails if it's not available. https://www.psycopg.org/psycopg3/docs/api/pq.html https://www.psycopg.org/psycopg3/docs/api/pq.html