Fix a problem causing the sessions module to occasionally lose track of rows

with composite primary keys when there are two rows with the same text value
in the leftmost column of the PK.

FossilOrigin-Name: 09aed13678374bf22087cd808808b711dc703b7c18bc8aaf704850611e17f5cd

ext/session/sessionH.test

@@ -0,0 +1,39 @@
+# 2018 January 18
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+
+if {![info exists testdir]} {
+  set testdir [file join [file dirname [info script]] .. .. test]
+} 
+source [file join [file dirname [info script]] session_common.tcl]
+source $testdir/tester.tcl
+ifcapable !session {finish_test; return}
+set testprefix sessionH
+
+forcedelete test.db2
+sqlite3 db2 test.db2
+
+do_test 1.0 {
+  do_common_sql {
+    CREATE TABLE t1(a, b, c, PRIMARY KEY(a, b));
+  }
+  do_then_apply_sql {
+    WITH s(i) AS (
+      VALUES(1) UNION ALL SELECT i+1 FROM s WHERe i<10000
+    )
+    INSERT INTO t1 SELECT 'abcde', randomblob(16), i FROM s;
+  }
+  compare_db db db2
+} {}
+
+
+finish_test
+

ext/session/sessionat.test

@@ -241,5 +241,9 @@ eval [string map [list %WR% $trailing] {
 }]
 }
 
+catch { db close }
+catch { db2 close }
+sqlite3_shutdown
+test_sqlite3_log
 
 finish_test

ext/session/sqlite3session.c

@@ -838,7 +838,6 @@ static int sessionPreupdateEqual(
         }
         if( memcmp(a, z, n) ) return 0;
         a += n;
-        break;
       }
     }
   }

manifest

@@ -1,5 +1,5 @@
-C Fix\smain.mk\sso\sthat\stestfixture\scan\sbe\sbuilt\seither\sfrom\sthe\samalgamation\sor\nfrom\sindividual\ssource\sfiles.\sNo\schanges\sto\scode.
+C Fix\sa\sproblem\scausing\sthe\ssessions\smodule\sto\soccasionally\slose\strack\sof\srows\nwith\scomposite\sprimary\skeys\swhen\sthere\sare\stwo\srows\swith\sthe\ssame\stext\svalue\nin\sthe\sleftmost\scolumn\sof\sthe\sPK.
-D 2018-01-17T16:11:26.562
+D 2018-01-17T17:38:18.448
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in 38f84f301cbef443b2d269f67a74b8cc536469831f70df7c3e912acc04932cc2
@@ -391,15 +391,16 @@ F ext/session/sessionD.test d3617e29aa15c9413aee5286d99587633245d58d2ad28f3f331c
 F ext/session/sessionE.test 0a616c4ad8fd2c05f23217ebb6212ef80b7fef30f5f086a6633a081f93e84637
 F ext/session/sessionF.test c2f178d4dfd723a5fd94a730ea2ccb44c669e3ce
 F ext/session/sessionG.test 63f9a744341d670775af29e4f19c1ef09a4810798400f28cd76704803a2e56ff
+F ext/session/sessionH.test 332b60e4c2e0a680105e11936201cabe378216f307e2747803cea56fa7d9ebae
 F ext/session/session_common.tcl 7776eda579773113b30c7abfd4545c445228cb73
 F ext/session/session_speed_test.c edc1f96fd5e0e4b16eb03e2a73041013d59e8723
-F ext/session/sessionat.test feb7d22b3124882064b9d9df69f5484a9bb8c123dc9ddc6ffcd357521848139f
+F ext/session/sessionat.test efe88965e74ff1bc2af9c310b28358c02d420c1fb2705cc7a28f0c1cc142c3ec
 F ext/session/sessiondiff.test ad13dd65664bae26744e1f18eb3cbd5588349b7e9118851d8f9364248d67bcec
 F ext/session/sessionfault.test da273f2712b6411e85e71465a1733b8501dbf6f7
 F ext/session/sessionfault2.test 04aa0bc9aa70ea43d8de82c4f648db4de1e990b0
 F ext/session/sessionstat1.test e3a3f5876ce1526b48f6f447ee0b18960ac683e3fc891791e1ca0c08e823d498
 F ext/session/sessionwor.test 2f3744236dc8b170a695b7d8ddc8c743c7e79fdc
-F ext/session/sqlite3session.c a18bfdab0de090597fb50aae734e2cd41bf5e5d394bbd9a2189308f2bc8525d5
+F ext/session/sqlite3session.c c9d813ffa8db0670257da0a0c931e7188dfbb0010bf1a38274775c9b6300dd5c
 F ext/session/sqlite3session.h cb4d860101ba6d3ac810f18684539b766d24d668fa2436cdde90d711af9464fb
 F ext/session/test_session.c eb0bd6c1ea791c1d66ee4ef94c16500dad936386
 F ext/userauth/sqlite3userauth.h 7f3ea8c4686db8e40b0a0e7a8e0b00fac13aa7a3
@@ -1699,7 +1700,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P bfbeffab7735461acb3773242ba31dae15af9f8b0291c54a6734747bb1b36e66
+P a8aea925f8fde8f2dc5ff4b744d54aa2bf8916f3ee57f22d77fd1ddb5a35a9cc
-R ec2f214ab6dea8dc121fe027cc99d1ce
+R fffe7fea955e558a2fcc7877bcdc39db
 U dan
-Z d15337a42013c6ddacd72bec21ca6a84
+Z 8da05c1c6303c10ad33f099cfa382df7

manifest.uuid

@@ -1 +1 @@
-a8aea925f8fde8f2dc5ff4b744d54aa2bf8916f3ee57f22d77fd1ddb5a35a9cc
+09aed13678374bf22087cd808808b711dc703b7c18bc8aaf704850611e17f5cd