Index: ext/fts3/fts3.c
==================================================================
--- ext/fts3/fts3.c
+++ ext/fts3/fts3.c
@@ -2768,11 +2768,11 @@
   ** Fts3SegReaderPending might segfault, as the data structures used by 
   ** fts4aux are not completely populated. So it's easiest to filter these
   ** calls out here.  */
   if( iLevel<0 && p->aIndex ){
     Fts3SegReader *pSeg = 0;
-    rc = sqlite3Fts3SegReaderPending(p, iIndex, zTerm, nTerm, isPrefix, &pSeg);
+    rc = sqlite3Fts3SegReaderPending(p, iIndex, zTerm, nTerm, isPrefix||isScan, &pSeg);
     if( rc==SQLITE_OK && pSeg ){
       rc = fts3SegReaderCursorAppend(pCsr, pSeg);
     }
   }
 

Index: ext/fts3/fts3_write.c
==================================================================
--- ext/fts3/fts3_write.c
+++ ext/fts3/fts3_write.c
@@ -324,11 +324,11 @@
 /* 23 */  "REPLACE INTO %Q.'%q_stat' VALUES(?,?)",
 /* 24 */  "",
 /* 25 */  "",
 
 /* 26 */ "DELETE FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
-/* 27 */ "SELECT DISTINCT level / (1024 * ?) FROM %Q.'%q_segdir'",
+/* 27 */ "SELECT ? UNION SELECT level / (1024 * ?) FROM %Q.'%q_segdir'",
 
 /* This statement is used to determine which level to read the input from
 ** when performing an incremental merge. It returns the absolute level number
 ** of the oldest level in the db that contains at least ? segments. Or,
 ** if no level in the FTS index contains more than ? segments, the statement
@@ -3439,11 +3439,12 @@
   sqlite3_stmt *pAllLangid = 0;
 
   rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
   if( rc==SQLITE_OK ){
     int rc2;
-    sqlite3_bind_int(pAllLangid, 1, p->nIndex);
+    sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
+    sqlite3_bind_int(pAllLangid, 2, p->nIndex);
     while( sqlite3_step(pAllLangid)==SQLITE_ROW ){
       int i;
       int iLangid = sqlite3_column_int(pAllLangid, 0);
       for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
         rc = fts3SegmentMerge(p, iLangid, i, FTS3_SEGCURSOR_ALL);
@@ -4771,11 +4772,11 @@
   while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
 
   pHint->n = i;
   i += sqlite3Fts3GetVarint(&pHint->a[i], piAbsLevel);
   i += fts3GetVarint32(&pHint->a[i], pnInput);
-  if( i!=nHint ) return SQLITE_CORRUPT_VTAB;
+  if( i!=nHint ) return FTS_CORRUPT_VTAB;
 
   return SQLITE_OK;
 }
 
 
@@ -5139,11 +5140,12 @@
 
   /* This block calculates the checksum according to the FTS index. */
   rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
   if( rc==SQLITE_OK ){
     int rc2;
-    sqlite3_bind_int(pAllLangid, 1, p->nIndex);
+    sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
+    sqlite3_bind_int(pAllLangid, 2, p->nIndex);
     while( rc==SQLITE_OK && sqlite3_step(pAllLangid)==SQLITE_ROW ){
       int iLangid = sqlite3_column_int(pAllLangid, 0);
       int i;
       for(i=0; i<p->nIndex; i++){
         cksum1 = cksum1 ^ fts3ChecksumIndex(p, iLangid, i, &rc);
@@ -5152,11 +5154,10 @@
     rc2 = sqlite3_reset(pAllLangid);
     if( rc==SQLITE_OK ) rc = rc2;
   }
 
   /* This block calculates the checksum according to the %_content table */
-  rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
   if( rc==SQLITE_OK ){
     sqlite3_tokenizer_module const *pModule = p->pTokenizer->pModule;
     sqlite3_stmt *pStmt = 0;
     char *zSql;
    
@@ -5249,11 +5250,11 @@
   Fts3Table *p                    /* FTS3 table handle */
 ){
   int rc;
   int bOk = 0;
   rc = fts3IntegrityCheck(p, &bOk);
-  if( rc==SQLITE_OK && bOk==0 ) rc = SQLITE_CORRUPT_VTAB;
+  if( rc==SQLITE_OK && bOk==0 ) rc = FTS_CORRUPT_VTAB;
   return rc;
 }
 
 /*
 ** Handle a 'special' INSERT of the form:

Index: test/fts4check.test
==================================================================
--- test/fts4check.test
+++ test/fts4check.test
@@ -176,8 +176,38 @@
   catchsql {
     INSERT INTO t4(t4) VALUES('integrity-check');
   }
 } {1 {database disk image is malformed}}
 reset_db
+
+#--------------------------------------------------------------------------
+# Test case 5.*
+#
+# Test that the integrity-check works if there is uncommitted data.
+#
+do_execsql_test 5.0 {
+  BEGIN;
+  CREATE VIRTUAL TABLE t5 USING fts4(a, prefix="1,2,3");
+  INSERT INTO t5 VALUES('And down by Kosiosko, where the reed-banks sweep');
+  INSERT INTO t5 VALUES('and sway, and the rolling plains are wide, the');
+  INSERT INTO t5 VALUES('man from snowy river is a household name today,');
+  INSERT INTO t5 VALUES('and the stockmen tell the story of his ride');
+}
+
+do_execsql_test 5.1 {
+  INSERT INTO t5(t5) VALUES('integrity-check');
+} {}
+
+do_catchsql_test 5.2 {
+  INSERT INTO t5_content VALUES(5, 'his hardy mountain pony');
+  INSERT INTO t5(t5) VALUES('integrity-check');
+} {1 {database disk image is malformed}}
+
+do_execsql_test 5.3 ROLLBACK
+
+do_execsql_test 5.4 {
+  CREATE VIRTUAL TABLE t5 USING fts4(a, prefix="1,2,3");
+  INSERT INTO t5(t5) VALUES('integrity-check');
+} {}
 
 finish_test
 

Index: test/trace2.test
==================================================================
--- test/trace2.test
+++ test/trace2.test
@@ -141,11 +141,11 @@
 
   do_trace_test 2.3 {
     INSERT INTO x1(x1) VALUES('optimize');
   } {
     "INSERT INTO x1(x1) VALUES('optimize');"
-    "-- SELECT DISTINCT level / (1024 * ?) FROM 'main'.'x1_segdir'"
+    "-- SELECT ? UNION SELECT level / (1024 * ?) FROM 'main'.'x1_segdir'"
     "-- SELECT idx, start_block, leaves_end_block, end_block, root FROM 'main'.'x1_segdir' WHERE level BETWEEN ? AND ?ORDER BY level DESC, idx ASC"
     "-- SELECT max(level) FROM 'main'.'x1_segdir' WHERE level BETWEEN ? AND ?"
     "-- SELECT coalesce((SELECT max(blockid) FROM 'main'.'x1_segments') + 1, 1)"
     "-- DELETE FROM 'main'.'x1_segdir' WHERE level BETWEEN ? AND ?"
     "-- REPLACE INTO 'main'.'x1_segdir' VALUES(?,?,?,?,?,?)"