porsas 
Nopea kuin sika pakkasella
Spike to see how fast we can go with both Clojure + JDBC & Async SQL. Highly Experimental.
Related dicsussion: https://clojureverse.org/t/next-jdbc-early-access/4091
Latest version
Basics
porsas provides tools for precompiling the functions to convert database results into Clojure values. This enables basically Java-fast database queries using idiomatic Clojure.
SQL queries are executed against a Context, which caches compiled row transformation functions based on database metadata.
There are different Context implementations:
- JDBC, a standalone JDBC implementation
- Async SQL, non-blocking SQL access
- jdbc.next, plugin for
next.jdbc
Currently, only eager query-one and query functions are supported.
Performance
At least an order of magnitude faster than clojure.java.jdbc, see the tests for more details.
Usage
JDBC
With defaults:
(require '[porsas.jdbc])
(def ctx (jdbc/context))
(jdbc/query-one ctx connection ["select * from fruit where appearance = ?" "red"])
; {:ID 1, :NAME "Apple", :APPEARANCE "red", :COST 59, :GRADE 87.0}Returning maps with qualified keys:
(def ctx
(jdbc/context
{:key (jdbc/qualified-key)}))
(jdbc/query-one ctx connection ["select * from fruit where appearance = ?" "red"])
; #:FRUIT{:ID 1, :NAME "Apple", :APPEARANCE "red", :COST 59, :GRADE 87.0}Generate Records for each unique Resultset, with lowercased keys. NOTE: this feature uses runtime code generation, so it doesn't work under GraalVM:
(def ctx
(jdbc/context
{:row (jdbc/rs->compiled-record)
:key (jdbc/unqualified-key str/lower-case)}))
(jdbc/query-one ctx connection ["select * from fruit where appearance = ?" "red"])
; ; => #user.DBResult6208{:id 1, :name "Apple", :appearance "red", :cost 59, :grade 87.0}Context can be omitted, bypassing all caching. Can be used when performance doesn't matter, e.g. when exploring in REPL:
(jdbc/query-one connection ["select * from fruit where appearance = ?" "red"])
; {:ID 1, :NAME "Apple", :APPEARANCE "red", :COST 59, :GRADE 87.0}Async SQL
Uses non-blocking vertx-sql-client and can be used with libraries like Promesa and Manifold.
(require '[porsas.async :as async])
(def ctx (async/context))
;; define a pool
(def pool
(async/pool
{:uri "postgresql://localhost:5432/hello_world"
:user "benchmarkdbuser"
:password "benchmarkdbpass"
:size 16}))
(-> (async/query-one ctx pool ["SELECT randomnumber from WORLD where id=$1" 1])
(async/then :randomnumber)
(async/then println))
; prints 504A blocking call:
(-> (async/query-one ctx pool ["SELECT randomnumber from WORLD where id=$1" 1])
(async/then :randomnumber)
(deref))With Promesa
(require '[promesa.core :as p])
(-> (pa/query-one ctx pool ["SELECT randomnumber from WORLD where id=$1" 1])
(p/chain :randomnumber println))
; #<Promise[~]>
; printls 504With Manifold
(require '[manifold.deferred :as d])
(-> (pa/query-one ctx pool ["SELECT randomnumber from WORLD where id=$1" 1])
(d/chain :randomnumber println))
; << … >>
; printls 504next.jdbc
Using porsas with :builder-fn option of next.jdbc:
(require '[porsas.next])
(require '[next.jdbc])
(def builder-fn (porsas.next/caching-row-builder))
(next.jdbc/execute-one! connection ["select * from fruit where appearance = ?" "red"] {:builder-fn builder-fn})
; #:FRUIT{:ID 1, :NAME "Apple", :APPEARANCE "red", :COST 59, :GRADE 87.0}More info
There is #sql in Clojurians Slack for discussion & help.
Roadmap as issues.
License
Copyright © 2019 Metosin Oy
Distributed under the Eclipse Public License, the same as Clojure.
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