diff --git a/ext/session/session1.test b/ext/session/session1.test
index 7aebe8c000..e97aa3c20d 100644
--- a/ext/session/session1.test
+++ b/ext/session/session1.test
@@ -206,8 +206,8 @@ do_conflict_test 3.1.2 -tables t1 -sql {
   INSERT INTO t1 VALUES(7, 'seven');
   INSERT INTO t1 VALUES(8, NULL);
 } -conflicts {
-  {INSERT t1 CONSTRAINT {i 8 n {}}}
   {INSERT t1 CONFLICT {i 6 t six} {i 6 t VI}}
+  {INSERT t1 CONSTRAINT {i 8 n {}}}
 }
 
 do_db2_test 3.1.3 "SELECT * FROM t1" {
@@ -272,9 +272,9 @@ do_conflict_test 3.3.3 -tables t4 -sql {
   UPDATE t4 SET a = NULL WHERE c = 9;
   UPDATE t4 SET a = 'x' WHERE b = 11;
 } -conflicts {
-  {UPDATE t4 CONSTRAINT {i 7 i 8 i 9} {n {} {} {} {} {}}}
   {UPDATE t4 DATA {i 1 i 2 i 3} {i -1 {} {} {} {}} {i 0 i 2 i 3}}
   {UPDATE t4 NOTFOUND {i 4 i 5 i 6} {i -1 {} {} {} {}}}
+  {UPDATE t4 CONSTRAINT {i 7 i 8 i 9} {n {} {} {} {} {}}}
 }
 do_db2_test     3.3.4 { SELECT * FROM t4 } {0 2 3 4 5 7 7 8 9 x 11 12}
 do_execsql_test 3.3.5 { SELECT * FROM t4 } {-1 2 3 -1 5 6 {} 8 9 x 11 12}
diff --git a/ext/session/sessionG.test b/ext/session/sessionG.test
new file mode 100644
index 0000000000..5c057350e4
--- /dev/null
+++ b/ext/session/sessionG.test
@@ -0,0 +1,177 @@
+# 2016 March 30
+#
+# 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.
+#
+#***********************************************************************
+#
+# This file implements regression tests for the sessions module.
+# Specifically, it tests that UNIQUE constraints are dealt with correctly.
+#
+
+
+
+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 sessionG
+
+
+forcedelete test.db2
+sqlite3 db2 test.db2
+
+do_test 1.0 {
+  do_common_sql {
+    CREATE TABLE t1(a PRIMARY KEY, b UNIQUE);
+    INSERT INTO t1 VALUES(1, 'one');
+    INSERT INTO t1 VALUES(2, 'two');
+    INSERT INTO t1 VALUES(3, 'three');
+  }
+  do_then_apply_sql {
+    DELETE FROM t1 WHERE a=1;
+    INSERT INTO t1 VALUES(4, 'one');
+  }
+  compare_db db db2
+} {}
+
+do_test 1.1 {
+  do_then_apply_sql {
+    DELETE FROM t1 WHERE a=4;
+    INSERT INTO t1 VALUES(1, 'one');
+  }
+  compare_db db db2
+} {}
+
+do_test 1.2 {
+  execsql { INSERT INTO t1 VALUES(5, 'five') } db2
+  do_then_apply_sql {
+    INSERT INTO t1 VALUES(11, 'eleven');
+    INSERT INTO t1 VALUES(12, 'five');
+  }
+  execsql { SELECT * FROM t1 } db2
+} {2 two 3 three 1 one 5 five 11 eleven}
+
+do_test 1.3 {
+  execsql { SELECT * FROM t1 }
+} {2 two 3 three 1 one 11 eleven 12 five}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+db2 close
+forcedelete test.db2
+sqlite3 db2 test.db2
+
+do_test 2.1 {
+  do_common_sql {
+    CREATE TABLE t1(a PRIMARY KEY, b UNIQUE, c UNIQUE);
+    INSERT INTO t1 VALUES(1, 1, 1);
+    INSERT INTO t1 VALUES(2, 2, 2);
+    INSERT INTO t1 VALUES(3, 3, 3);
+  }
+} {}
+
+do_test 2.2.1 {
+  # It is not possible to apply the changeset generated by the following
+  # SQL, as none of the three updated rows may be updated as part of the
+  # first pass.
+  do_then_apply_sql {
+    UPDATE t1 SET b=0 WHERE a=1;
+    UPDATE t1 SET b=1 WHERE a=2;
+    UPDATE t1 SET b=2 WHERE a=3;
+    UPDATE t1 SET b=3 WHERE a=1;
+  }
+  db2 eval { SELECT a, b FROM t1 }
+} {1 1 2 2 3 3}
+do_test 2.2.2 { db eval { SELECT a, b FROM t1 } } {1 3 2 1 3 2}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+db2 close
+forcedelete test.db2
+sqlite3 db2 test.db2
+
+do_test 3.1 {
+  do_common_sql {
+    CREATE TABLE t1(a PRIMARY KEY, b UNIQUE, c UNIQUE);
+    INSERT INTO t1 VALUES(1, 1, 1);
+    INSERT INTO t1 VALUES(2, 2, 2);
+    INSERT INTO t1 VALUES(3, 3, 3);
+  }
+} {}
+
+do_test 3.3 {
+  do_then_apply_sql {
+    UPDATE t1 SET b=4 WHERE a=3;
+    UPDATE t1 SET b=3 WHERE a=2;
+    UPDATE t1 SET b=2 WHERE a=1;
+  }
+  compare_db db db2
+} {}
+
+do_test 3.4 {
+  do_then_apply_sql {
+    UPDATE t1 SET b=1 WHERE a=1;
+    UPDATE t1 SET b=2 WHERE a=2;
+    UPDATE t1 SET b=3 WHERE a=3;
+  }
+  compare_db db db2
+} {}
+
+#-------------------------------------------------------------------------
+#
+reset_db
+db2 close
+forcedelete test.db2
+sqlite3 db2 test.db2
+
+do_test 4.1 {
+  do_common_sql {
+    CREATE TABLE t1(a PRIMARY KEY, b UNIQUE);
+    INSERT INTO t1 VALUES(1, 1);
+    INSERT INTO t1 VALUES(2, 2);
+    INSERT INTO t1 VALUES(3, 3);
+
+    CREATE TABLE t2(a PRIMARY KEY, b UNIQUE);
+    INSERT INTO t2 VALUES(1, 1);
+    INSERT INTO t2 VALUES(2, 2);
+    INSERT INTO t2 VALUES(3, 3);
+  }
+} {}
+
+do_test 4.2 {
+  do_then_apply_sql {
+    UPDATE t1 SET b=4 WHERE a=3;
+    UPDATE t1 SET b=3 WHERE a=2;
+    UPDATE t1 SET b=2 WHERE a=1;
+
+    UPDATE t2 SET b=0 WHERE a=1;
+    UPDATE t2 SET b=1 WHERE a=2;
+    UPDATE t2 SET b=2 WHERE a=3;
+  }
+  compare_db db db2
+} {}
+
+do_test 4.3 {
+  do_then_apply_sql {
+    UPDATE t1 SET b=1 WHERE a=1;
+    UPDATE t1 SET b=2 WHERE a=2;
+    UPDATE t1 SET b=3 WHERE a=3;
+
+    UPDATE t2 SET b=3 WHERE a=3;
+    UPDATE t2 SET b=2 WHERE a=2;
+    UPDATE t2 SET b=1 WHERE a=1;
+  }
+  compare_db db db2
+} {}
+
+finish_test
+
diff --git a/ext/session/sessionfault2.test b/ext/session/sessionfault2.test
new file mode 100644
index 0000000000..6b257cf41b
--- /dev/null
+++ b/ext/session/sessionfault2.test
@@ -0,0 +1,106 @@
+# 2016 March 31
+#
+# 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.
+#
+#***********************************************************************
+#
+# The focus of this file is testing the session module.
+#
+
+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
+set testprefix sessionfault2
+
+do_execsql_test 1.0.0 {
+  CREATE TABLE t1(a PRIMARY KEY, b UNIQUE);
+  INSERT INTO t1 VALUES(1, 1);
+  INSERT INTO t1 VALUES(2, 2);
+  INSERT INTO t1 VALUES(3, 3);
+
+  CREATE TABLE t2(a PRIMARY KEY, b UNIQUE);
+  INSERT INTO t2 VALUES(1, 1);
+  INSERT INTO t2 VALUES(2, 2);
+  INSERT INTO t2 VALUES(3, 3);
+}
+faultsim_save_and_close
+
+faultsim_restore_and_reopen
+do_test 1.0.1 {
+  set ::C [changeset_from_sql {
+    UPDATE t1 SET b=4 WHERE a=3;
+    UPDATE t1 SET b=3 WHERE a=2;
+    UPDATE t1 SET b=2 WHERE a=1;
+    UPDATE t2 SET b=0 WHERE a=1;
+    UPDATE t2 SET b=1 WHERE a=2;
+    UPDATE t2 SET b=2 WHERE a=3;
+  }]
+  set {} {}
+} {}
+
+proc xConflict args { return "OMIT" }
+
+do_faultsim_test 1 -faults oom-p* -prep {
+  faultsim_restore_and_reopen
+} -body {
+  sqlite3changeset_apply db $::C xConflict
+} -test {
+  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
+  faultsim_integrity_check
+
+  catch { db eval ROLLBACK }
+  set res [db eval {
+    SELECT * FROM t1;
+    SELECT * FROM t2;
+  }]
+
+  if {$testrc==0} {
+    if {$res != "1 2 2 3 3 4 1 0 2 1 3 2"} { error "data error" }
+  } else {
+    if {
+         $res != "1 2 2 3 3 4 1 0 2 1 3 2"
+      && $res != "1 1 2 2 3 3 1 1 2 2 3 3"
+    } { error "data error!! $res" }
+  }
+}
+
+#-------------------------------------------------------------------------
+# OOM when applying a changeset for which one of the tables has a name
+# 99 bytes in size. This happens to cause an extra malloc in within the
+# sessions_strm permutation.
+#
+reset_db
+set nm [string repeat t 99]
+do_execsql_test 2.0.0 [string map "%TBL% $nm" {
+  CREATE TABLE %TBL%(a PRIMARY KEY, b UNIQUE);
+}]
+faultsim_save_and_close
+
+faultsim_restore_and_reopen
+do_test 1.0.1 {
+  set ::C [changeset_from_sql [string map "%TBL% $nm" {
+    INSERT INTO %TBL% VALUES(1, 2);
+    INSERT INTO %TBL% VALUES(3, 4);
+  }]]
+  set {} {}
+} {}
+
+proc xConflict args { return "OMIT" }
+do_faultsim_test 2 -faults oom-p* -prep {
+  faultsim_restore_and_reopen
+} -body {
+  sqlite3changeset_apply db $::C xConflict
+} -test {
+  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
+  faultsim_integrity_check
+}
+
+finish_test
+
diff --git a/ext/session/sqlite3session.c b/ext/session/sqlite3session.c
index 312e03dcfb..437549dd70 100644
--- a/ext/session/sqlite3session.c
+++ b/ext/session/sqlite3session.c
@@ -67,6 +67,8 @@ struct SessionBuffer {
 **  sqlite3changeset_start_strm()).
 */
 struct SessionInput {
+  int bNoDiscard;                 /* If true, discard no data */
+  int iCurrent;                   /* Offset in aData[] of current change */
   int iNext;                      /* Offset in aData[] of next change */
   u8 *aData;                      /* Pointer to buffer containing changeset */
   int nData;                      /* Number of bytes in aData */
@@ -175,7 +177,7 @@ struct SessionTable {
 **
 ** Followed by one or more changes to the table.
 **
-**   1 byte: Either SQLITE_INSERT, UPDATE or DELETE.
+**   1 byte: Either SQLITE_INSERT (0x12), UPDATE (0x17) or DELETE (0x09).
 **   1 byte: The "indirect-change" flag.
 **   old.* record: (delete and update only)
 **   new.* record: (insert and update only)
@@ -217,7 +219,7 @@ struct SessionTable {
 **
 ** Followed by one or more changes to the table.
 **
-**   1 byte: Either SQLITE_INSERT, UPDATE or DELETE.
+**   1 byte: Either SQLITE_INSERT (0x12), UPDATE (0x17) or DELETE (0x09).
 **   1 byte: The "indirect-change" flag.
 **   single record: (PK fields for DELETE, PK and modified fields for UPDATE,
 **                   full record for INSERT).
@@ -2460,7 +2462,6 @@ static int sessionChangesetStart(
   pRet->in.nData = nChangeset;
   pRet->in.xInput = xInput;
   pRet->in.pIn = pIn;
-  pRet->in.iNext = 0;
   pRet->in.bEof = (xInput ? 0 : 1);
 
   /* Populate the output variable and return success. */
@@ -2490,6 +2491,23 @@ int sqlite3changeset_start_strm(
   return sessionChangesetStart(pp, xInput, pIn, 0, 0);
 }
 
+/*
+** If the SessionInput object passed as the only argument is a streaming
+** object and the buffer is full, discard some data to free up space.
+*/
+static void sessionDiscardData(SessionInput *pIn){
+  if( pIn->bEof && pIn->xInput && pIn->iNext>=SESSIONS_STRM_CHUNK_SIZE ){
+    int nMove = pIn->buf.nBuf - pIn->iNext;
+    assert( nMove>=0 );
+    if( nMove>0 ){
+      memmove(pIn->buf.aBuf, &pIn->buf.aBuf[pIn->iNext], nMove);
+    }
+    pIn->buf.nBuf -= pIn->iNext;
+    pIn->iNext = 0;
+    pIn->nData = pIn->buf.nBuf;
+  }
+}
+
 /*
 ** Ensure that there are at least nByte bytes available in the buffer. Or,
 ** if there are not nByte bytes remaining in the input, that all available
@@ -2503,13 +2521,7 @@ static int sessionInputBuffer(SessionInput *pIn, int nByte){
     while( !pIn->bEof && (pIn->iNext+nByte)>=pIn->nData && rc==SQLITE_OK ){
       int nNew = SESSIONS_STRM_CHUNK_SIZE;
 
-      if( pIn->iNext>=SESSIONS_STRM_CHUNK_SIZE ){
-        int nMove = pIn->buf.nBuf - pIn->iNext;
-        memmove(pIn->buf.aBuf, &pIn->buf.aBuf[pIn->iNext], nMove);
-        pIn->buf.nBuf -= pIn->iNext;
-        pIn->iNext = 0;
-      }
-
+      if( pIn->bNoDiscard==0 ) sessionDiscardData(pIn);
       if( SQLITE_OK==sessionBufferGrow(&pIn->buf, nNew, &rc) ){
         rc = pIn->xInput(pIn->pIn, &pIn->buf.aBuf[pIn->buf.nBuf], &nNew);
         if( nNew==0 ){
@@ -2818,11 +2830,15 @@ static int sessionChangesetNext(
     return SQLITE_DONE;
   }
 
+  sessionDiscardData(&p->in);
+  p->in.iCurrent = p->in.iNext;
+
   op = p->in.aData[p->in.iNext++];
   if( op=='T' || op=='P' ){
     p->bPatchset = (op=='P');
     if( sessionChangesetReadTblhdr(p) ) return p->rc;
     if( (p->rc = sessionInputBuffer(&p->in, 2)) ) return p->rc;
+    p->in.iCurrent = p->in.iNext;
     op = p->in.aData[p->in.iNext++];
   }
 
@@ -3266,6 +3282,9 @@ struct SessionApplyCtx {
   int nCol;                       /* Size of azCol[] and abPK[] arrays */
   const char **azCol;             /* Array of column names */
   u8 *abPK;                       /* Boolean array - true if column is in PK */
+
+  int bDeferConstraints;          /* True to defer constraints */
+  SessionBuffer constraints;      /* Deferred constraints are stored here */
 };
 
 /*
@@ -3516,7 +3535,7 @@ static int sessionBindValue(
 ** transfers new.* values from the current iterator entry to statement
 ** pStmt. The table being inserted into has nCol columns.
 **
-** New.* value $i 0 from the iterator is bound to variable ($i+1) of 
+** New.* value $i from the iterator is bound to variable ($i+1) of 
 ** statement pStmt. If parameter abPK is NULL, all values from 0 to (nCol-1)
 ** are transfered to the statement. Otherwise, if abPK is not NULL, it points
 ** to an array nCol elements in size. In this case only those values for 
@@ -3662,9 +3681,18 @@ static int sessionConflictHandler(
     pIter->pConflict = 0;
     rc = sqlite3_reset(p->pSelect);
   }else if( rc==SQLITE_OK ){
-    /* No other row with the new.* primary key. */
-    res = xConflict(pCtx, eType+1, pIter);
-    if( res==SQLITE_CHANGESET_REPLACE ) rc = SQLITE_MISUSE;
+    if( p->bDeferConstraints && eType==SQLITE_CHANGESET_CONFLICT ){
+      /* Instead of invoking the conflict handler, append the change blob
+      ** to the SessionApplyCtx.constraints buffer. */
+      u8 *aBlob = &pIter->in.aData[pIter->in.iCurrent];
+      int nBlob = pIter->in.iNext - pIter->in.iCurrent;
+      sessionAppendBlob(&p->constraints, aBlob, nBlob, &rc);
+      res = SQLITE_CHANGESET_OMIT;
+    }else{
+      /* No other row with the new.* primary key. */
+      res = xConflict(pCtx, eType+1, pIter);
+      if( res==SQLITE_CHANGESET_REPLACE ) rc = SQLITE_MISUSE;
+    }
   }
 
   if( rc==SQLITE_OK ){
@@ -3824,6 +3852,120 @@ static int sessionApplyOneOp(
   return rc;
 }
 
+/*
+** Attempt to apply the change that the iterator passed as the first argument
+** currently points to to the database. If a conflict is encountered, invoke
+** the conflict handler callback.
+**
+** The difference between this function and sessionApplyOne() is that this
+** function handles the case where the conflict-handler is invoked and 
+** returns SQLITE_CHANGESET_REPLACE - indicating that the change should be
+** retried in some manner.
+*/
+static int sessionApplyOneWithRetry(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator to read change from */
+  SessionApplyCtx *pApply,        /* Apply context */
+  int(*xConflict)(void*, int, sqlite3_changeset_iter*),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  int bReplace = 0;
+  int bRetry = 0;
+  int rc;
+
+  rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, &bReplace, &bRetry);
+  assert( rc==SQLITE_OK || (bRetry==0 && bReplace==0) );
+
+  /* If the bRetry flag is set, the change has not been applied due to an
+  ** SQLITE_CHANGESET_DATA problem (i.e. this is an UPDATE or DELETE and
+  ** a row with the correct PK is present in the db, but one or more other
+  ** fields do not contain the expected values) and the conflict handler 
+  ** returned SQLITE_CHANGESET_REPLACE. In this case retry the operation,
+  ** but pass NULL as the final argument so that sessionApplyOneOp() ignores
+  ** the SQLITE_CHANGESET_DATA problem.  */
+  if( bRetry ){
+    assert( pIter->op==SQLITE_UPDATE || pIter->op==SQLITE_DELETE );
+    rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, 0, 0);
+  }
+
+  /* If the bReplace flag is set, the change is an INSERT that has not
+  ** been performed because the database already contains a row with the
+  ** specified primary key and the conflict handler returned
+  ** SQLITE_CHANGESET_REPLACE. In this case remove the conflicting row
+  ** before reattempting the INSERT.  */
+  else if( bReplace ){
+    assert( pIter->op==SQLITE_INSERT );
+    rc = sqlite3_exec(db, "SAVEPOINT replace_op", 0, 0, 0);
+    if( rc==SQLITE_OK ){
+      rc = sessionBindRow(pIter, 
+          sqlite3changeset_new, pApply->nCol, pApply->abPK, pApply->pDelete);
+      sqlite3_bind_int(pApply->pDelete, pApply->nCol+1, 1);
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3_step(pApply->pDelete);
+      rc = sqlite3_reset(pApply->pDelete);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, 0, 0);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_exec(db, "RELEASE replace_op", 0, 0, 0);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Retry the changes accumulated in the pApply->constraints buffer.
+*/
+static int sessionRetryConstraints(
+  sqlite3 *db, 
+  int bPatchset,
+  const char *zTab,
+  SessionApplyCtx *pApply,
+  int(*xConflict)(void*, int, sqlite3_changeset_iter*),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  int rc = SQLITE_OK;
+
+  while( pApply->constraints.nBuf ){
+    sqlite3_changeset_iter *pIter2 = 0;
+    SessionBuffer cons = pApply->constraints;
+    memset(&pApply->constraints, 0, sizeof(SessionBuffer));
+
+    rc = sessionChangesetStart(&pIter2, 0, 0, cons.nBuf, cons.aBuf);
+    if( rc==SQLITE_OK ){
+      int nByte = 2*pApply->nCol*sizeof(sqlite3_value*);
+      int rc2;
+      pIter2->bPatchset = bPatchset;
+      pIter2->zTab = (char*)zTab;
+      pIter2->nCol = pApply->nCol;
+      pIter2->abPK = pApply->abPK;
+      sessionBufferGrow(&pIter2->tblhdr, nByte, &rc);
+      pIter2->apValue = (sqlite3_value**)pIter2->tblhdr.aBuf;
+      if( rc==SQLITE_OK ) memset(pIter2->apValue, 0, nByte);
+
+      while( rc==SQLITE_OK && SQLITE_ROW==sqlite3changeset_next(pIter2) ){
+        rc = sessionApplyOneWithRetry(db, pIter2, pApply, xConflict, pCtx);
+      }
+
+      rc2 = sqlite3changeset_finalize(pIter2);
+      if( rc==SQLITE_OK ) rc = rc2;
+    }
+    assert( pApply->bDeferConstraints || pApply->constraints.nBuf==0 );
+
+    sqlite3_free(cons.aBuf);
+    if( rc!=SQLITE_OK ) break;
+    if( pApply->constraints.nBuf>=cons.nBuf ){
+      /* No progress was made on the last round. */
+      pApply->bDeferConstraints = 0;
+    }
+  }
+
+  return rc;
+}
+
 /*
 ** Argument pIter is a changeset iterator that has been initialized, but
 ** not yet passed to sqlite3changeset_next(). This function applies the 
@@ -3850,9 +3992,11 @@ static int sessionChangesetApply(
   const char *zTab = 0;           /* Name of current table */
   int nTab = 0;                   /* Result of sqlite3Strlen30(zTab) */
   SessionApplyCtx sApply;         /* changeset_apply() context object */
+  int bPatchset;
 
   assert( xConflict!=0 );
 
+  pIter->in.bNoDiscard = 1;
   memset(&sApply, 0, sizeof(sApply));
   sqlite3_mutex_enter(sqlite3_db_mutex(db));
   rc = sqlite3_exec(db, "SAVEPOINT changeset_apply", 0, 0, 0);
@@ -3862,8 +4006,6 @@ static int sessionChangesetApply(
   while( rc==SQLITE_OK && SQLITE_ROW==sqlite3changeset_next(pIter) ){
     int nCol;
     int op;
-    int bReplace = 0;
-    int bRetry = 0;
     const char *zNew;
     
     sqlite3changeset_op(pIter, &zNew, &nCol, &op, 0);
@@ -3871,6 +4013,11 @@ static int sessionChangesetApply(
     if( zTab==0 || sqlite3_strnicmp(zNew, zTab, nTab+1) ){
       u8 *abPK;
 
+      rc = sessionRetryConstraints(
+          db, pIter->bPatchset, zTab, &sApply, xConflict, pCtx
+      );
+      if( rc!=SQLITE_OK ) break;
+
       sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
       sqlite3_finalize(sApply.pDelete);
       sqlite3_finalize(sApply.pUpdate); 
@@ -3878,6 +4025,7 @@ static int sessionChangesetApply(
       sqlite3_finalize(sApply.pSelect);
       memset(&sApply, 0, sizeof(sApply));
       sApply.db = db;
+      sApply.bDeferConstraints = 1;
 
       /* If an xFilter() callback was specified, invoke it now. If the 
       ** xFilter callback returns zero, skip this table. If it returns
@@ -3933,39 +4081,20 @@ static int sessionChangesetApply(
     ** next change. A log message has already been issued. */
     if( schemaMismatch ) continue;
 
-    rc = sessionApplyOneOp(pIter, &sApply, xConflict, pCtx, &bReplace, &bRetry);
-
-    if( rc==SQLITE_OK && bRetry ){
-      rc = sessionApplyOneOp(pIter, &sApply, xConflict, pCtx, &bReplace, 0);
-    }
-
-    if( bReplace ){
-      assert( pIter->op==SQLITE_INSERT );
-      rc = sqlite3_exec(db, "SAVEPOINT replace_op", 0, 0, 0);
-      if( rc==SQLITE_OK ){
-        rc = sessionBindRow(pIter, 
-            sqlite3changeset_new, sApply.nCol, sApply.abPK, sApply.pDelete);
-        sqlite3_bind_int(sApply.pDelete, sApply.nCol+1, 1);
-      }
-      if( rc==SQLITE_OK ){
-        sqlite3_step(sApply.pDelete);
-        rc = sqlite3_reset(sApply.pDelete);
-      }
-      if( rc==SQLITE_OK ){
-        rc = sessionApplyOneOp(pIter, &sApply, xConflict, pCtx, 0, 0);
-      }
-      if( rc==SQLITE_OK ){
-        rc = sqlite3_exec(db, "RELEASE replace_op", 0, 0, 0);
-      }
-    }
+    rc = sessionApplyOneWithRetry(db, pIter, &sApply, xConflict, pCtx);
   }
 
+  bPatchset = pIter->bPatchset;
   if( rc==SQLITE_OK ){
     rc = sqlite3changeset_finalize(pIter);
   }else{
     sqlite3changeset_finalize(pIter);
   }
 
+  if( rc==SQLITE_OK ){
+    rc = sessionRetryConstraints(db, bPatchset, zTab, &sApply, xConflict, pCtx);
+  }
+
   if( rc==SQLITE_OK ){
     int nFk, notUsed;
     sqlite3_db_status(db, SQLITE_DBSTATUS_DEFERRED_FKS, &nFk, &notUsed, 0);
@@ -3994,6 +4123,7 @@ static int sessionChangesetApply(
   sqlite3_finalize(sApply.pUpdate);
   sqlite3_finalize(sApply.pSelect);
   sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
+  sqlite3_free((char*)sApply.constraints.aBuf);
   sqlite3_mutex_leave(sqlite3_db_mutex(db));
   return rc;
 }
diff --git a/manifest b/manifest
index deae1a11e9..c98d80b73d 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Minor\sperformance\soptimization\sin\sthe\scomparison\sopcodes\sof\sthe\sVDBE.
-D 2016-04-04T13:46:24.704
+C Enhance\ssqlite3session_apply()\sand\ssqlite3session_apply_strm()\sso\sthat\nconflicts\sare\sretried\sbefore\sthe\sxConflict()\scallback\sis\sinvoked,\sas\slong\nas\sthe\s"apply"\soperation\sis\smaking\sforward\sprogress.
+D 2016-04-04T14:57:25.972
 F Makefile.in e812bb732d7af01baa09f1278bd4f4a2e3a09449
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc fe57d7e3e74fa383fd01ced796c0ffd966fc094a
@@ -273,7 +273,7 @@ F ext/rtree/sqlite3rtree.h 9c5777af3d2921c7b4ae4954e8e5697502289d28
 F ext/rtree/tkt3363.test 142ab96eded44a3615ec79fba98c7bde7d0f96de
 F ext/rtree/viewrtree.tcl eea6224b3553599ae665b239bd827e182b466024
 F ext/session/changeset.c 4ccbaa4531944c24584bf6a61ba3a39c62b6267a
-F ext/session/session1.test 5dab50ce55c859e829bae24f0787013f51775fc5
+F ext/session/session1.test 98f384736e2bc21ccf5ed81bdadcff4ad863393b
 F ext/session/session2.test 284de45abae4cc1082bc52012ee81521d5ac58e0
 F ext/session/session3.test a7a9ce59b8d1e49e2cc23d81421ac485be0eea01
 F ext/session/session4.test a6ed685da7a5293c5d6f99855bcf41dbc352ca84
@@ -287,9 +287,11 @@ F ext/session/sessionC.test 97556f5164ac29f2344b24bd7de6a3a35a95c390
 F ext/session/sessionD.test d4744c78334162851d2a2f285c7e603e31b49aa2
 F ext/session/sessionE.test e60a238c47f0feb3bb707e7f35e22be09c7e8f26
 F ext/session/sessionF.test c2f178d4dfd723a5fd94a730ea2ccb44c669e3ce
+F ext/session/sessionG.test 01ef705096a9d3984eebdcca79807a211dee1b60
 F ext/session/session_common.tcl a1293167d14774b5e728836720497f40fe4ea596
 F ext/session/sessionfault.test d52cbb7bee48cc8ee80335e07eb72fcb6b15eb40
-F ext/session/sqlite3session.c b10af3e87ae437bb197b3a23a584d2dc8ad8981a
+F ext/session/sessionfault2.test ac1dfd77a0fb0ea310aee40a16645ef1b66d3f88
+F ext/session/sqlite3session.c 2fc72bd989c424a15802da766c7ebd8eed47bcf6
 F ext/session/sqlite3session.h 64e9e7f185725ef43b97f4a9a0c0df0669844f1d
 F ext/session/test_session.c 187bd344c5ae9d5be85e22ef7c3010f0c17307ce
 F ext/userauth/sqlite3userauth.h 19cb6f0e31316d0ee4afdfb7a85ef9da3333a220
@@ -1480,7 +1482,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 0213d6af84965676626c2fb4d78b4c74675207cc
-R 20833b687cd0398f4e539411826fc13a
+P e375fe52cea7903c11ecef71c3452c67a96b663e 49763fc3ae2fb6117b0443ea28661568467f9bf2
+R 29983b81bb4a270732770d4dd854ff08
+T +closed 49763fc3ae2fb6117b0443ea28661568467f9bf2
 U drh
-Z 68baca12d82e219ae03586c49d91929a
+Z eb92f633faf3f47383a6550496ee5fc7
diff --git a/manifest.uuid b/manifest.uuid
index b3dbcfbd15..586be52a36 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-e375fe52cea7903c11ecef71c3452c67a96b663e
\ No newline at end of file
+42a219668413e18dae917b03b04a21d108cc44be
\ No newline at end of file