Allow serialization errors through internal error handling.

project.clj

@@ -1,4 +1,4 @@
-(defproject views "0.4.3"
+(defproject views "0.4.4"
   :description "You underestimate the power of the SQL side"
 
   :url "https://github.com/diligenceengine/views"

src/views/db/deltas.clj

@@ -1,4 +1,5 @@
 (ns views.db.deltas
+  (:import (java.sql SQLException))
   (:require
    [clojure.string :refer [split]]
    [clojure.java.jdbc :as j]
@@ -8,7 +9,7 @@
    [views.db.load :as vdbl]
    [views.db.checks :as vc]
    [views.db.honeysql :as vh]
-   [views.db.util :refer [safe-map log-exception]]))
+   [views.db.util :refer [safe-map log-exception serialization-error?]]))
 
 ;;
 ;; Terminology and data structures used throughout this code
@@ -218,9 +219,10 @@
        (try
          (let [refresh-set (get (vdbl/initial-view db view-sig templates view) view-sig)]
            (update-in d [view-sig] (update-deltas-with-refresh-set refresh-set)))
-         (catch Exception e ;; ignore any failed view deltas
+         ;; allow serialization errors
-           (log-exception e)
+         (catch SQLException e (if (serialization-error? e) (throw e) d))
-           d)))
+         ;; ignore any failed view deltas
+         (catch Exception e (log-exception e) d)))
      deltas
      refresh-only-views))
 

src/views/db/util.clj

@@ -9,7 +9,7 @@
 ;; java.sql.SQLException: ERROR: could not serialize access due to concurrent update
 ;;
 (defn get-nested-exceptions*
-  [exceptions e]
+  [exceptions ^SQLException e]
   (if-let [next-e (.getNextException e)]
     (recur (conj exceptions next-e) next-e)
     exceptions))
@@ -19,6 +19,11 @@
   [e]
   (get-nested-exceptions* [e] e))
 
+(defn serialization-error?
+  "True if e is a serialization error."
+  [^SQLException e]
+  (boolean (some #(= (.getSQLState ^SQLException %) "40001") (get-nested-exceptions e))))
+
 ;; TODO: update to avoid stack overflow.
 (defn retry-on-transaction-failure
   "Retry a function whenever we receive a transaction failure."
@@ -31,7 +36,7 @@
       (debug "Exception message: " (.getMessage e))
 
       ;; (debug "stack trace message: " (.printStackTrace e))
-      (if (some #(= (.getSQLState %) "40001") (get-nested-exceptions e))
+      (if (serialization-error? e)
         (retry-on-transaction-failure transaction-fn) ;; try it again
         (throw e))))) ;; otherwise rethrow
 
@@ -42,7 +47,7 @@
     (retry-on-transaction-failure tfn#)))
 
 (defn log-exception
-  [e]
+  [^Exception e]
   (error "views internal"
          (str
            "e: "      e
@@ -50,6 +55,11 @@
            " trace: " (with-out-str (print-stack-trace e)))))
 
 (defn safe-map
-  "A non-lazy map that skips any results that throw exeptions."
+  "A non-lazy map that skips any results that throw exeptions other than SQL
+  serialization errors."
   [f items]
-  (reduce #(try (conj %1 (f %2)) (catch Exception e %1)) [] items))
+  (reduce #(try (conj %1 (f %2))
+                (catch SQLException e (if (serialization-error? e) (throw e) %1))
+                (catch Exception e %1))
+          []
+          items))