This is useful if your postgresql version is dependant on `system.stateVersion` and not pinned down manually. Then it's not necessary to find out which version exactly is in use and define `package` manually, but just stay with what NixOS provides as default: $ nix-instantiate -A postgresql /nix/store/82fzmb77mz2b787dgj7mn4a8i4f6l6sn-postgresql-14.7.drv $ nix-instantiate -A postgresql_jit /nix/store/qsjkb72fcrrfpsszrwbsi9q9wgp39m50-postgresql-14.7.drv $ nix-instantiate -A postgresql.withJIT /nix/store/qsjkb72fcrrfpsszrwbsi9q9wgp39m50-postgresql-14.7.drv $ nix-instantiate -A postgresql.withJIT.withoutJIT /nix/store/82fzmb77mz2b787dgj7mn4a8i4f6l6sn-postgresql-14.7.drv I.e. you can use postgresql with JIT (for complex queries only[1]) like this: services.postgresql = { enable = true; enableJIT = true; }; Performing a new override instead of re-using the `_jit`-variants for that has the nice property that overlays for the original package apply to the JIT-enabled variant, i.e. with import ./. { overlays = [ (self: super: { postgresql = super.postgresql.overrideAttrs (_: { fnord = "snens"; }); }) ]; }; postgresql.withJIT.fnord still gives the string `snens` whereas `postgresql_jit` doesn't have the attribute `fnord` in its derivation. [1] https://www.postgresql.org/docs/current/runtime-config-query.html#GUC-JIT-ABOVE-COST |
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.. | ||
administration | ||
configuration | ||
development | ||
installation | ||
manpages | ||
release-notes | ||
contributing-to-this-manual.chapter.md | ||
default.nix | ||
man-pages.xml | ||
manual.md | ||
nixos-options.md | ||
preface.md | ||
README.md |