Index: ext/fts5/fts5Int.h
==================================================================
--- ext/fts5/fts5Int.h
+++ ext/fts5/fts5Int.h
@@ -84,10 +84,11 @@
 
   /* Values loaded from the %_config table */
   int iCookie;                    /* Incremented when %_config is modified */
   int pgsz;                       /* Approximate page size used in %_data */
   int nAutomerge;                 /* 'automerge' setting */
+  int nCrisisMerge;               /* Maximum allowed segments per level */
   char *zRank;                    /* Name of rank function */
   char *zRankArgs;                /* Arguments to rank function */
 };
 
 #define FTS5_CONTENT_NORMAL   0

Index: ext/fts5/fts5_config.c
==================================================================
--- ext/fts5/fts5_config.c
+++ ext/fts5/fts5_config.c
@@ -15,10 +15,11 @@
 
 #include "fts5Int.h"
 
 #define FTS5_DEFAULT_PAGE_SIZE   1000
 #define FTS5_DEFAULT_AUTOMERGE      4
+#define FTS5_DEFAULT_CRISISMERGE   16
 
 /* Maximum allowed page size */
 #define FTS5_MAX_PAGE_SIZE (128*1024)
 
 static int fts5_iswhitespace(char x){
@@ -714,10 +715,23 @@
     }else{
       if( nAutomerge==1 ) nAutomerge = FTS5_DEFAULT_AUTOMERGE;
       pConfig->nAutomerge = nAutomerge;
     }
   }
+
+  else if( 0==sqlite3_stricmp(zKey, "crisismerge") ){
+    int nCrisisMerge = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nCrisisMerge = sqlite3_value_int(pVal);
+    }
+    if( nCrisisMerge<0 ){
+      if( pbBadkey ) *pbBadkey = 1;
+    }else{
+      if( nCrisisMerge<=1 ) nCrisisMerge = FTS5_DEFAULT_CRISISMERGE;
+      pConfig->nCrisisMerge = nCrisisMerge;
+    }
+  }
 
   else if( 0==sqlite3_stricmp(zKey, "rank") ){
     const char *zIn = (const char*)sqlite3_value_text(pVal);
     char *zRank;
     char *zRankArgs;
@@ -747,10 +761,11 @@
   int rc;
 
   /* Set default values */
   pConfig->pgsz = FTS5_DEFAULT_PAGE_SIZE;
   pConfig->nAutomerge = FTS5_DEFAULT_AUTOMERGE;
+  pConfig->nCrisisMerge = FTS5_DEFAULT_CRISISMERGE;
 
   zSql = sqlite3_mprintf(zSelect, pConfig->zDb, pConfig->zName);
   if( zSql==0 ){
     rc = SQLITE_NOMEM;
   }else{

Index: ext/fts5/fts5_index.c
==================================================================
--- ext/fts5/fts5_index.c
+++ ext/fts5/fts5_index.c
@@ -41,11 +41,10 @@
 **
 */
 
 #define FTS5_OPT_WORK_UNIT  1000  /* Number of leaf pages per optimize step */
 #define FTS5_WORK_UNIT      64    /* Number of leaf pages in unit of work */
-#define FTS5_CRISIS_MERGE   16    /* Maximum number of segments to merge */
 
 #define FTS5_MIN_DLIDX_SIZE  4    /* Add dlidx if this many empty pages */
 
 /*
 ** Details:
@@ -291,11 +290,10 @@
 ** One object per %_data table.
 */
 struct Fts5Index {
   Fts5Config *pConfig;            /* Virtual table configuration */
   char *zDataTbl;                 /* Name of %_data table */
-  int nCrisisMerge;               /* Maximum allowed segments per level */
   int nWorkUnit;                  /* Leaf pages in a "unit" of work */
 
   /*
   ** Variables related to the accumulation of tokens and doclists within the
   ** in-memory hash tables before they are flushed to disk.
@@ -1103,12 +1101,12 @@
   assert( iIdx<=pConfig->nPrefix );
   pData = fts5DataRead(p, FTS5_STRUCTURE_ROWID(iIdx));
   if( !pData ) return 0;
   p->rc = fts5StructureDecode(pData->p, pData->n, &iCookie, &pRet);
 
-  if( p->rc==SQLITE_OK && p->pConfig->iCookie!=iCookie ){
-    p->rc = sqlite3Fts5ConfigLoad(p->pConfig, iCookie);
+  if( p->rc==SQLITE_OK && pConfig->iCookie!=iCookie ){
+    p->rc = sqlite3Fts5ConfigLoad(pConfig, iCookie);
   }
 
   fts5DataRelease(pData);
   if( p->rc!=SQLITE_OK ){
     fts5StructureRelease(pRet);
@@ -1248,24 +1246,23 @@
   if( p->rc==SQLITE_OK ){
     int iTst;
     int iPromote = -1;
     int szPromote;                /* Promote anything this size or smaller */
     Fts5StructureSegment *pSeg;   /* Segment just written */
-    Fts5StructureLevel *pTst;
     int szSeg;                    /* Size of segment just written */
 
 
     pSeg = &pStruct->aLevel[iLvl].aSeg[pStruct->aLevel[iLvl].nSeg-1];
     szSeg = (1 + pSeg->pgnoLast - pSeg->pgnoFirst);
 
     /* Check for condition (a) */
     for(iTst=iLvl-1; iTst>=0 && pStruct->aLevel[iTst].nSeg==0; iTst--);
-    pTst = &pStruct->aLevel[iTst];
-    assert( pTst->nMerge==0 );
     if( iTst>=0 ){
       int i;
       int szMax = 0;
+      Fts5StructureLevel *pTst = &pStruct->aLevel[iTst];
+      assert( pTst->nMerge==0 );
       for(i=0; i<pTst->nSeg; i++){
         int sz = pTst->aSeg[i].pgnoLast - pTst->aSeg[i].pgnoFirst + 1;
         if( sz>szMax ) szMax = sz;
       }
       if( szMax>=szSeg ){
@@ -2481,32 +2478,10 @@
 */
 static int fts5PosIterEof(Fts5Index *p, Fts5PosIter *pIter){
   return (p->rc || pIter->chunk.pLeaf==0);
 }
 
-/*
-** Add an entry for (iRowid/iCol/iPos) to the doclist for (pToken/nToken)
-** in hash table for index iIdx. If iIdx is zero, this is the main terms 
-** index. Values of 1 and greater for iIdx are prefix indexes.
-**
-** If an OOM error is encountered, set the Fts5Index.rc error code 
-** accordingly.
-*/
-static void fts5AddTermToHash(
-  Fts5Index *p,                   /* Index object to write to */
-  int iIdx,                       /* Entry in p->aHash[] to update */
-  int iCol,                       /* Column token appears in (-ve -> delete) */
-  int iPos,                       /* Position of token within column */
-  const char *pToken, int nToken  /* Token to add or remove to or from index */
-){
-  if( p->rc==SQLITE_OK ){
-    p->rc = sqlite3Fts5HashWrite(
-        p->apHash[iIdx], p->iWriteRowid, iCol, iPos, pToken, nToken
-    );
-  }
-}
-
 /*
 ** Allocate a new segment-id for the structure pStruct.
 **
 ** If an error has already occurred, this function is a no-op. 0 is 
 ** returned in this case.
@@ -3226,11 +3201,11 @@
 ){
   Fts5Structure *pStruct = *ppStruct;
   int iLvl = 0;
   while( p->rc==SQLITE_OK 
       && iLvl<pStruct->nLevel
-      && pStruct->aLevel[iLvl].nSeg>=p->nCrisisMerge 
+      && pStruct->aLevel[iLvl].nSeg>=p->pConfig->nCrisisMerge 
   ){
     fts5IndexMergeLevel(p, iIdx, &pStruct, iLvl, 0);
     fts5StructurePromote(p, iLvl+1, pStruct);
     iLvl++;
   }
@@ -3998,10 +3973,33 @@
 ** Indicate that all subsequent calls to sqlite3Fts5IndexWrite() pertain
 ** to the document with rowid iRowid.
 */
 int sqlite3Fts5IndexBeginWrite(Fts5Index *p, i64 iRowid){
   assert( p->rc==SQLITE_OK );
+
+  /* Allocate hash tables if they have not already been allocated */
+  if( p->apHash==0 ){
+    int i;
+    int rc = SQLITE_OK;
+    int nHash = p->pConfig->nPrefix + 1;
+    Fts5Hash **apNew;
+
+    apNew = (Fts5Hash**)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Hash*)*nHash);
+    for(i=0; rc==SQLITE_OK && i<nHash; i++){
+      rc = sqlite3Fts5HashNew(&apNew[i], &p->nPendingData);
+    }
+    if( rc==SQLITE_OK ){
+      p->apHash = apNew;
+    }else{
+      for(i=0; i<nHash; i++){
+        sqlite3Fts5HashFree(apNew[i]);
+      }
+      sqlite3_free(apNew);
+      return rc;
+    }
+  }
+
   if( iRowid<=p->iWriteRowid || (p->nPendingData > p->nMaxPendingData) ){
     fts5IndexFlush(p);
   }
   p->iWriteRowid = iRowid;
   return fts5IndexReturn(p);
@@ -4069,11 +4067,10 @@
   *pp = p = (Fts5Index*)sqlite3_malloc(sizeof(Fts5Index));
   if( !p ) return SQLITE_NOMEM;
 
   memset(p, 0, sizeof(Fts5Index));
   p->pConfig = pConfig;
-  p->nCrisisMerge = FTS5_CRISIS_MERGE;
   p->nWorkUnit = FTS5_WORK_UNIT;
   p->nMaxPendingData = 1024*1024;
   p->zDataTbl = sqlite3_mprintf("%s_data", pConfig->zName);
   if( p->zDataTbl==0 ){
     rc = SQLITE_NOMEM;
@@ -4194,33 +4191,30 @@
   int iCol,                       /* Column token appears in (-ve -> delete) */
   int iPos,                       /* Position of token within column */
   const char *pToken, int nToken  /* Token to add or remove to or from index */
 ){
   int i;                          /* Used to iterate through indexes */
+  int rc;                         /* Return code */
   Fts5Config *pConfig = p->pConfig;
+
   assert( p->rc==SQLITE_OK );
 
-  /* Allocate hash tables if they have not already been allocated */
-  if( p->apHash==0 ){
-    int nHash = pConfig->nPrefix + 1;
-    p->apHash = (Fts5Hash**)fts5IdxMalloc(p, sizeof(Fts5Hash*) * nHash);
-    for(i=0; p->rc==SQLITE_OK && i<nHash; i++){
-      p->rc = sqlite3Fts5HashNew(&p->apHash[i], &p->nPendingData);
-    }
-  }
-
   /* Add the new token to the main terms hash table. And to each of the
   ** prefix hash tables that it is large enough for. */
-  fts5AddTermToHash(p, 0, iCol, iPos, pToken, nToken);
-  for(i=0; i<pConfig->nPrefix; i++){
+  rc = sqlite3Fts5HashWrite(
+      p->apHash[0], p->iWriteRowid, iCol, iPos, pToken, nToken
+  );
+  for(i=0; i<pConfig->nPrefix && rc==SQLITE_OK; i++){
     int nByte = fts5IndexCharlenToBytelen(pToken, nToken, pConfig->aPrefix[i]);
     if( nByte ){
-      fts5AddTermToHash(p, i+1, iCol, iPos, pToken, nByte);
+      rc = sqlite3Fts5HashWrite(
+          p->apHash[i+1], p->iWriteRowid, iCol, iPos, pToken, nByte
+      );
     }
   }
 
-  return fts5IndexReturn(p);
+  return rc;
 }
 
 /*
 ** Open a new iterator to iterate though all docids that match the 
 ** specified token or token prefix.

Index: ext/fts5/tool/loadfts5.tcl
==================================================================
--- ext/fts5/tool/loadfts5.tcl
+++ ext/fts5/tool/loadfts5.tcl
@@ -27,17 +27,19 @@
   puts stderr "  -fts4        (use fts4 instead of fts5)"
   puts stderr "  -fts5        (use fts5)"
   puts stderr "  -porter      (use porter tokenizer)"
   puts stderr "  -limit N     (load no more than N documents)"
   puts stderr "  -automerge N (set the automerge parameter to N)"
+  puts stderr "  -crisismerge N (set the crisismerge parameter to N)"
   exit 1
 }
 
 set O(vtab)       fts5
 set O(tok)        ""
 set O(limit)      0
 set O(automerge)  -1
+set O(crisismerge)  -1
 
 if {[llength $argv]<2} usage
 set nOpt [expr {[llength $argv]-2}]
 for {set i 0} {$i < $nOpt} {incr i} {
   set arg [lindex $argv $i]
@@ -61,10 +63,15 @@
     
     -automerge {
       if { [incr i]>=$nOpt } usage
       set O(automerge) [lindex $argv $i]
     }
+
+    -crisismerge {
+      if { [incr i]>=$nOpt } usage
+      set O(crisismerge) [lindex $argv $i]
+    }
 
     default {
       usage
     }
   }
@@ -79,11 +86,17 @@
     if {$O(vtab) == "fts5"} {
       db eval { INSERT INTO t1(t1, rank) VALUES('automerge', $O(automerge)) }
     } else {
       db eval { INSERT INTO t1(t1) VALUES('automerge=' || $O(automerge)) }
     }
+  }
+  if {$O(crisismerge)>=0} {
+    if {$O(vtab) == "fts5"} {
+      db eval {INSERT INTO t1(t1, rank) VALUES('crisismerge', $O(crisismerge))}
+    } else {
+    }
   }
   load_hierachy [lindex $argv end]
 }