(PDB-3059) Add memoize-resource-identity-hashes opt

Add a boolean memoize-resource-identity-hashes option to the developer
config section that defaults to true (the existing behavior), and will
disable the resource hash memoization (for the whole JVM) when set to
false.

project.clj

@@ -1,4 +1,4 @@
-(def pdb-version "4.1.2")
+(def pdb-version "4.1.2-hotfix-3059")
 
 (defn deploy-info
   "Generate deployment information from the URL supplied and the username and

src/puppetlabs/puppetdb/cli/services.clj

@@ -61,6 +61,7 @@
             [puppetlabs.puppetdb.query-eng :as qeng]
             [puppetlabs.puppetdb.query.population :as pop]
             [puppetlabs.puppetdb.scf.migrate :refer [migrate! indexes!]]
+            [puppetlabs.puppetdb.scf.hash :as scf-hash]
             [puppetlabs.puppetdb.scf.storage :as scf-store]
             [puppetlabs.puppetdb.scf.storage-utils :as sutils]
             [puppetlabs.puppetdb.time :refer [to-seconds to-millis parse-period
@@ -256,6 +257,9 @@
     (when-let [v (version/version)]
       (log/infof "PuppetDB version %s" v))
 
+    (reset! scf-hash/memoize-resource-identity-hashes?
+            (:memoize-resource-identity-hashes developer))
+
     (init-with-db database config)
 
     (let [population-registry (get-in metrics/metrics-registries [:population :registry])]

src/puppetlabs/puppetdb/config.clj

@@ -178,10 +178,12 @@
 
 (def developer-config-in
   (all-optional
-    {:pretty-print (pls/defaulted-maybe String "false")}))
+   {:pretty-print (pls/defaulted-maybe String "false")
+    :memoize-resource-identity-hashes (pls/defaulted-maybe String "true")}))
 
 (def developer-config-out
-  {:pretty-print Boolean})
+  {:pretty-print Boolean
+   :memoize-resource-identity-hashes Boolean})
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; Database config

src/puppetlabs/puppetdb/scf/hash.clj

@@ -50,6 +50,8 @@
 ;; "medium" site persona
 (def memoized-resource-identity-hash* (kitchensink/bounded-memoize resource-identity-hash* 40000))
 
+(def memoize-resource-identity-hashes? (atom true))
+
 (defn resource-identity-hash
   "Compute a hash for a given resource that will uniquely identify it
   _for storage deduplication only_.
@@ -60,7 +62,9 @@
   [{:keys [type title parameters] :as resource}]
   {:pre  [(map? resource)]
    :post [(string? %)]}
-  (memoized-resource-identity-hash* type title parameters))
+  (if @memoize-resource-identity-hashes?
+    (memoized-resource-identity-hash* type title parameters)
+    (resource-identity-hash* type title parameters)))
 
 (defn catalog-resource-identity-format
   "Narrow `resource` to only contain the needed key/values for computing the hash of