From ebe0eb6c2d19daa954ca5dd9f3781ed075ab62e2 Mon Sep 17 00:00:00 2001
From: Huahai Yang <huahai.yang@gmail.com>
Date: Mon, 20 Jul 2020 23:44:34 -0700
Subject: [PATCH] reset transaction after obtaining entries

---
 CHANGELOG.md                 |  3 +++
 src/datalevin/constants.cljc |  2 +-
 src/datalevin/lmdb.clj       | 10 +++++++---
 test/datalevin/lmdb_test.clj |  8 ++++++++
 4 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cd0c192e..b5fd7162 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 All notable changes to this project will be documented in this file. This change log follows the conventions of [keepachangelog.com](http://keepachangelog.com/).
 
 ## WIP
+## Fixed
+- Reset transaction after getting entries
+- Only use 24 reader slots
 
 ## 0.2.4
 ## Fixed
diff --git a/src/datalevin/constants.cljc b/src/datalevin/constants.cljc
index 32317690..094ee2ab 100644
--- a/src/datalevin/constants.cljc
+++ b/src/datalevin/constants.cljc
@@ -19,7 +19,7 @@
 
 (def ^:const +max-dbs+          128)
 (def ^:const +max-readers+      126)
-(def ^:const +use-readers+      64)    ; leave the rest to others
+(def ^:const +use-readers+      24)    ; leave the rest to others
 (def ^:const +init-db-size+     100)   ; in megabytes
 (def ^:const +default-val-size+ 16384) ; in bytes
 (def ^:const +max-key-size+     511)   ; in bytes
diff --git a/src/datalevin/lmdb.clj b/src/datalevin/lmdb.clj
index b9651613..4ff8e912 100644
--- a/src/datalevin/lmdb.clj
+++ b/src/datalevin/lmdb.clj
@@ -559,9 +559,13 @@
   (entries [this dbi-name]
     (assert (not (closed? this)) "LMDB env is closed.")
     (let [^DBI dbi   (get-dbi this dbi-name)
-          ^Rtx rtx   (get-rtx pool)
-          ^Stat stat (.stat ^Dbi (.-db dbi) (.-txn rtx))]
-      (.-entries stat)))
+          ^Rtx rtx   (get-rtx pool)]
+      (try
+        (.-entries ^Stat (.stat ^Dbi (.-db dbi) (.-txn rtx)))
+        (catch Exception e
+          (raise "Fail to get entries: " (ex-message e)
+                 {:dbi dbi-name}))
+        (finally (reset rtx)))))
 
   (transact [this txs]
     (assert (not (closed? this)) "LMDB env is closed.")
diff --git a/test/datalevin/lmdb_test.clj b/test/datalevin/lmdb_test.clj
index d66854d1..e60fc2d9 100644
--- a/test/datalevin/lmdb_test.clj
+++ b/test/datalevin/lmdb_test.clj
@@ -45,6 +45,10 @@
                    [:put "b" :long 1 :data :long]
                    [:put "b" 2 3 :long :long]]))
 
+  (testing "entries"
+    (is (= 6 (sut/entries lmdb "a")))
+    (is (= 9 (sut/entries lmdb "b"))))
+
   (testing "get-value"
     (is (= 2 (sut/get-value lmdb "a" 1)))
     (is (= [1 2] (sut/get-value lmdb "a" 1 :data :data false)))
@@ -71,6 +75,10 @@
                         [:del "a" :non-exist]])
     (is (nil? (sut/get-value lmdb "a" 1))))
 
+  (testing "entries-again"
+    (is (= 5 (sut/entries lmdb "a")))
+    (is (= 9 (sut/entries lmdb "b"))))
+
   (testing "non-existent dbi"
     (is (thrown-with-msg? Exception #"open-dbi" (sut/get-value lmdb "z" 1))))