Search API returns irrelevant results

[Pzixel]

Describe the bug
When querying https://crates.io/api/v1/crates results are invalid sometimes

To Reproduce
Steps to reproduce the behavior:

A:

1. Go to https://crates.io/api/v1/crates?page=1&per_page=20&q=rust_dec&sort=
2. Observe that results page doesn't have a single rust_dec word, but it produces some irrelevant crates like aocleaderboard, atomic-traits and others

B:

1. Go to https://crates.io/api/v1/crates?page=1&per_page=20&q=rust_dec
2. Observe that results page contains rust_dec word, but it also produces some irrelevant crates like z3d, google_maps and others

Expected behavior
It should show the same result as https://crates.io/api/v1/crates?page=1&per_page=20&q=rust_deci&sort= query (note i in the end of the query):

{
   "crates":[
      {
         "id":"rust_decimal",
         "name":"rust_decimal",
         "updated_at":"2020-12-28T16:53:45.360679+00:00",
         "versions":null,
         "keywords":null,
         "categories":null,
         "badges":[
            
         ],
         "created_at":"2016-11-16T16:31:13.547828+00:00",
         "downloads":814045,
         "recent_downloads":210946,
         "max_version":"1.9.0",
         "newest_version":"1.9.0",
         "max_stable_version":"1.9.0",
         "description":"A Decimal Implementation written in pure Rust suitable for financial calculations.",
         "homepage":null,
         "documentation":"https://docs.rs/rust_decimal/",
         "repository":"https://github.com/paupino/rust-decimal",
         "links":{
            "version_downloads":"/api/v1/crates/rust_decimal/downloads",
            "versions":"/api/v1/crates/rust_decimal/versions",
            "owners":"/api/v1/crates/rust_decimal/owners",
            "owner_team":"/api/v1/crates/rust_decimal/owner_team",
            "owner_user":"/api/v1/crates/rust_decimal/owner_user",
            "reverse_dependencies":"/api/v1/crates/rust_decimal/reverse_dependencies"
         },
         "exact_match":false
      },
      {
         "id":"rust_decimal_macro_impls",
         "name":"rust_decimal_macro_impls",
         "updated_at":"2020-07-11T21:49:51.446673+00:00",
         "versions":null,
         "keywords":null,
         "categories":null,
         "badges":[
            
         ],
         "created_at":"2019-02-03T03:22:12.536585+00:00",
         "downloads":32018,
         "recent_downloads":1174,
         "max_version":"1.7.0",
         "newest_version":"1.7.0",
         "max_stable_version":"1.7.0",
         "description":"Shorthand macros to assist creating Decimal types. Do not depend on this directly; use rust_decimal_macros",
         "homepage":null,
         "documentation":"https://docs.rs/rust_decimal/",
         "repository":"https://github.com/paupino/rust-decimal",
         "links":{
            "version_downloads":"/api/v1/crates/rust_decimal_macro_impls/downloads",
            "versions":"/api/v1/crates/rust_decimal_macro_impls/versions",
            "owners":"/api/v1/crates/rust_decimal_macro_impls/owners",
            "owner_team":"/api/v1/crates/rust_decimal_macro_impls/owner_team",
            "owner_user":"/api/v1/crates/rust_decimal_macro_impls/owner_user",
            "reverse_dependencies":"/api/v1/crates/rust_decimal_macro_impls/reverse_dependencies"
         },
         "exact_match":false
      },
      {
         "id":"rust_decimal_macros",
         "name":"rust_decimal_macros",
         "updated_at":"2020-12-28T16:54:49.057667+00:00",
         "versions":null,
         "keywords":null,
         "categories":null,
         "badges":[
            
         ],
         "created_at":"2017-11-11T19:29:52.110872+00:00",
         "downloads":60126,
         "recent_downloads":21243,
         "max_version":"1.9.0",
         "newest_version":"1.9.0",
         "max_stable_version":"1.9.0",
         "description":"Shorthand macros to assist creating Decimal types.",
         "homepage":null,
         "documentation":"https://docs.rs/rust_decimal/",
         "repository":"https://github.com/paupino/rust-decimal",
         "links":{
            "version_downloads":"/api/v1/crates/rust_decimal_macros/downloads",
            "versions":"/api/v1/crates/rust_decimal_macros/versions",
            "owners":"/api/v1/crates/rust_decimal_macros/owners",
            "owner_team":"/api/v1/crates/rust_decimal_macros/owner_team",
            "owner_user":"/api/v1/crates/rust_decimal_macros/owner_user",
            "reverse_dependencies":"/api/v1/crates/rust_decimal_macros/reverse_dependencies"
         },
         "exact_match":false
      }
   ],
   "meta":{
      "total":3,
      "next_page":null,
      "prev_page":null
   }
}

Screenshots

[Turbo87]

thanks for reporting this @Pzixel. I share your view that the search algorithm needs to be improved, though at the moment it is not clear for us yet exactly how we can improve it. We have a similar issue already reported at #2739, so I'll go ahead and close this one as a duplicate. :)