C binding for leveldb, better readseq benchmark for SQLite.

- Added a C binding for LevelDB.
  May be useful as a stable ABI that can be used by 
  programs that keep leveldb in a shared library, 
  or for JNI API.

- Replaced SQLite's readseq benchmark to a more efficient version. 
  SQLite readseq speeds increased by about a factor of 2x 
  from the previous version. Also updated benchmark page to
  reflect readseq speed up.



git-svn-id: https://leveldb.googlecode.com/svn/trunk@46 62dab493-f737-651d-591e-8d6aee1b9529

2 files changed, 25 insertions, 15 deletions

diff --git a/doc/bench/db_bench_sqlite3.cc b/doc/bench/db_bench_sqlite3.cc
index a15510e..e11db52 100644
--- a/doc/bench/db_bench_sqlite3.cc
+++ b/doc/bench/db_bench_sqlite3.cc
@@ -23,7 +23,6 @@
 //   fillseq100K   -- write N/1000 100K values in sequential order in async mode
 //   readseq       -- read N times sequentially
 //   readrandom    -- read N times in random order
-//   readseq100K   -- read N/1000 100K values in sequential order in async mode
 //   readrand100K  -- read N/1000 100K values in sequential order in async mode
 static const char* FLAGS_benchmarks =
     "fillseq,"
@@ -38,7 +37,7 @@ static const char* FLAGS_benchmarks =
     "readseq,"
     "fillrand100K,"
     "fillseq100K,"
-    "readseq100K,"
+    "readseq,"
     "readrand100K,"
     ;
 
@@ -387,7 +386,7 @@ class Benchmark {
         Write(write_sync, SEQUENTIAL, FRESH, num_ / 1000, 100 * 1000, 1);
         WalCheckpoint(db_);
       } else if (name == Slice("readseq")) {
-        Read(SEQUENTIAL, 1);
+        ReadSequential();
       } else if (name == Slice("readrandom")) {
         Read(RANDOM, 1);
       } else if (name == Slice("readrand100K")) {
@@ -395,11 +394,6 @@ class Benchmark {
         reads_ /= 1000;
         Read(RANDOM, 1);
         reads_ = n;
-      } else if (name == Slice("readseq100K")) {
-        int n = reads_;
-        reads_ /= 1000;
-        Read(SEQUENTIAL, 1);
-        reads_ = n;
       } else {
         known = false;
         if (name != Slice()) {  // No error message for empty name
@@ -640,6 +634,22 @@ class Benchmark {
     ErrorCheck(status);
   }
 
+  void ReadSequential() {
+    int status;
+    sqlite3_stmt *pStmt;
+    std::string read_str = "SELECT * FROM test ORDER BY key";
+
+    status = sqlite3_prepare_v2(db_, read_str.c_str(), -1, &pStmt, NULL);
+    ErrorCheck(status);
+    for (int i = 0; i < reads_ && SQLITE_ROW == sqlite3_step(pStmt); i++) {
+      bytes_ += sqlite3_column_bytes(pStmt, 1) + sqlite3_column_bytes(pStmt, 2);
+      FinishedSingleOp();
+    }
+
+    status = sqlite3_finalize(pStmt);
+    ErrorCheck(status);
+  }
+
 };
 
 }
diff --git a/doc/benchmark.html b/doc/benchmark.html
index a0d6b02..c463977 100644
--- a/doc/benchmark.html
+++ b/doc/benchmark.html
@@ -130,8 +130,8 @@ parameters are varied.  For the baseline:</p>
     <td class="c2">1,010,000 ops/sec</td>
     <td class="c3"><div class="bkct" style="width:95px">&nbsp;</div></td>
 <tr><td class="c1">SQLite3</td>
-    <td class="c2">174,000 ops/sec</td>
-    <td class="c3"><div class="bsql" style="width:15px">&nbsp;</div></td>
+    <td class="c2">383,000 ops/sec</td>
+    <td class="c3"><div class="bsql" style="width:33px">&nbsp;</div></td>
 </table>
 <h3>B. Random Reads</h3>
 <table class="bn bnbase">
@@ -386,9 +386,9 @@ MB.</p>
     <td class="c3"><div class="bkct" style="width:72px">&nbsp;</div></td>
     <td class="c4">(1.06x baseline)</td></tr>
 <tr><td class="c1">SQLite3</td>
-    <td class="c2">210,000 ops/sec</td>
-    <td class="c3"><div class="bsql" style="width:14px">&nbsp;</div></td>
-    <td class="c4">(1.20x baseline)</td></tr>
+    <td class="c2">609,000 ops/sec</td>
+    <td class="c3"><div class="bsql" style="width:41px">&nbsp;</div></td>
+    <td class="c4">(1.59x baseline)</td></tr>
 </table>
 
 <h4>Random Reads</h4>
@@ -425,8 +425,8 @@ database.</p>
     <td class="c3"><div class="bkct" style="width:88px">&nbsp;</div></td>
     <td class="c4">(3.60x baseline)</td></tr>
 <tr><td class="c1">SQLite3</td>
-    <td class="c2">174,000 ops/sec</td>
-    <td class="c3"><div class="bsql" style="width:13px">&nbsp;</div></td>
+    <td class="c2">383,000 ops/sec</td>
+    <td class="c3"><div class="bsql" style="width:27px">&nbsp;</div></td>
     <td class="c4">(1.00x baseline)</td></tr>
 </table>
 <h4>Random Reads</h4>