datahike.pg.sql.database — org.replikativ/pg-datahike 0.1.367

CREATE DATABASE / DROP DATABASE token-driven parser plus the db-from-template helper used to wire a server-level config template to a per-database config.

JSqlParser 5.x has no AST class for either statement (returns UnsupportedStatement), so we hand-parse before JSqlParser sees the SQL. The grammar accepted is:

CREATE DATABASE name [WITH] [(] [k [=] v [,]]* [)] DROP DATABASE [IF EXISTS] name [WITH (FORCE)]

name is either a bare identifier or a quoted identifier ("..."). Option values are 'string', "ident", number, true|false, or a bare identifier.

Datahike-aware option keys are translated into datahike config:

BACKEND -> [:store :backend] keyword STORE_ID -> [:store :id] string PATH -> [:store :path] string (file backend) HOST / PORT / USER / -> [:store :*] string|long PASSWORD / DBNAME (pg backend) SCHEMA_FLEXIBILITY -> :schema-flexibility keyword KEEP_HISTORY -> :keep-history? boolean INDEX -> :index :datahike.index/<value>

PostgreSQL-only option keys (OWNER, TEMPLATE, ENCODING, LC_COLLATE, LC_CTYPE, LOCALE, LOCALE_PROVIDER, ICU_LOCALE, ICU_RULES, COLLATION_VERSION, TABLESPACE, ALLOW_CONNECTIONS, CONNECTION_LIMIT, IS_TEMPLATE, OID, STRATEGY, REFRESH_COLLATION_VERSION) are silently accepted with a NOTICE so pg_dump output round-trips.

Unknown option names raise :syntax-error.

db-delete-from-template clj

(db-delete-from-template _server-template)

Build an :on-delete-database hook that mirrors db-from-template: release the conn and delete ITS backing store.

The store is the one the conn was opened on, read from the conn. Rebuilding it from the template, as this did, gave an in-memory store a FRESH random :id (ensure-store-id), so delete-database deleted a store that never existed -- silently, under the catch -- and the dropped database stayed in the memory backend's registry, reachable for the life of the process. pg_regress creates and drops a fixture database per file; a run kept every one of them, about 400k datoms each, and that is why its harness restarted the server every 30 files.

db-from-template clj

(db-from-template server-template)

Build an :on-create-database hook from a server-level config template. The returned fn receives [db-name parsed-options], merges options over the template, interpolates {{name}}, ensures a UUID :id, then runs d/create-database and d/connect and returns the connection.

Example template: {:store {:backend :memory} :schema-flexibility :write :keep-history? false}

With {{name}} interpolation: {:store {:backend :file :path "/var/lib/dh/{{name}}"} :schema-flexibility :write}

ensure-value-caps clj

(ensure-value-caps cfg)

Default a server-created database to UNBOUNDED value sizes unless the operator's template says otherwise.

Datahike leaves value-size caps opt-in and warns once per create-database that they are unset. The nudge is aimed at Datalog applications; for a PostgreSQL surrogate the answer is not the :value-caps :default preset, because that is Datomic parity — 4096 characters for a string — and PostgreSQL's text is bounded only by the 1GB varlena limit. Adopting the preset would reject values a real PostgreSQL accepts, so we record the unbounded choice explicitly (:max-string-length 0 disables the cap) rather than inherit a silent 4096.

An operator who wants caps sets them in the template and keeps them.

options->config clj

(options->config server-template options)

Apply parsed options on top of server-template. Returns {:config datahike-config :notices [str ...]}. Throws :syntax-error on an unknown non-pg option.

parse-create-database clj

(parse-create-database toks)

Parse a tokenised CREATE DATABASE statement. Returns: {:db-name str :if-not-exists? bool :options [[lower-case-key value] ...]}

The grammar is intentionally lenient — WITH is optional, (...) is optional, = between key and value is optional, , between pairs is optional. Each option value is decoded as the right Clojure type (string for 'literal', long for digits, boolean for true/false, raw string otherwise).

parse-drop-database clj

(parse-drop-database toks)

Parse a tokenised DROP DATABASE statement. Returns: {:db-name str :if-exists? bool}

WITH (FORCE) is silently accepted but ignored — Datahike connections are released as part of the drop regardless.

tokenize clj

(tokenize sql)

Tokenize a SQL string into a vector of [kind text-or-value] pairs. Tokens: :ident :string :num :bool :eq :comma :lparen :rparen :semicolon.