diff --git a/ext/session/session1.test b/ext/session/session1.test
index f423a0cf4b..0eb850a795 100644
--- a/ext/session/session1.test
+++ b/ext/session/session1.test
@@ -655,6 +655,13 @@ do_test $tn.13.3 {
 } {1 one 2 two 3 iii}
 execsql ROLLBACK
 
+do_test $tn.14.1 { sqlite3session_config strm_size -1 } 64
+do_test $tn.14.2 { sqlite3session_config strm_size 65536 } 65536
+do_test $tn.14.3 { sqlite3session_config strm_size 64 } 64
+do_test $tn.14.4 { 
+  list [catch {sqlite3session_config invalid 123} msg] $msg
+} {1 SQLITE_MISUSE}
+
 }]
 }
 
diff --git a/ext/session/sqlite3session.c b/ext/session/sqlite3session.c
index 1a7f003eb6..108b74ca2a 100644
--- a/ext/session/sqlite3session.c
+++ b/ext/session/sqlite3session.c
@@ -25,6 +25,8 @@ typedef struct SessionInput SessionInput;
 # endif
 #endif
 
+static int sessions_strm_chunk_size = SESSIONS_STRM_CHUNK_SIZE;
+
 typedef struct SessionHook SessionHook;
 struct SessionHook {
   void *pCtx;
@@ -2397,12 +2399,12 @@ static int sessionGenerateChangeset(
             rc = sqlite3_reset(pSel);
           }
 
-          /* If the buffer is now larger than SESSIONS_STRM_CHUNK_SIZE, pass
+          /* If the buffer is now larger than sessions_strm_chunk_size, pass
           ** its contents to the xOutput() callback. */
           if( xOutput 
            && rc==SQLITE_OK 
            && buf.nBuf>nNoop 
-           && buf.nBuf>SESSIONS_STRM_CHUNK_SIZE 
+           && buf.nBuf>sessions_strm_chunk_size 
           ){
             rc = xOutput(pOut, (void*)buf.aBuf, buf.nBuf);
             nNoop = -1;
@@ -2614,7 +2616,7 @@ int sqlite3changeset_start_v2_strm(
 ** object and the buffer is full, discard some data to free up space.
 */
 static void sessionDiscardData(SessionInput *pIn){
-  if( pIn->xInput && pIn->iNext>=SESSIONS_STRM_CHUNK_SIZE ){
+  if( pIn->xInput && pIn->iNext>=sessions_strm_chunk_size ){
     int nMove = pIn->buf.nBuf - pIn->iNext;
     assert( nMove>=0 );
     if( nMove>0 ){
@@ -2637,7 +2639,7 @@ static int sessionInputBuffer(SessionInput *pIn, int nByte){
   int rc = SQLITE_OK;
   if( pIn->xInput ){
     while( !pIn->bEof && (pIn->iNext+nByte)>=pIn->nData && rc==SQLITE_OK ){
-      int nNew = SESSIONS_STRM_CHUNK_SIZE;
+      int nNew = sessions_strm_chunk_size;
 
       if( pIn->bNoDiscard==0 ) sessionDiscardData(pIn);
       if( SQLITE_OK==sessionBufferGrow(&pIn->buf, nNew, &rc) ){
@@ -3362,7 +3364,7 @@ static int sessionChangesetInvert(
     }
 
     assert( rc==SQLITE_OK );
-    if( xOutput && sOut.nBuf>=SESSIONS_STRM_CHUNK_SIZE ){
+    if( xOutput && sOut.nBuf>=sessions_strm_chunk_size ){
       rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
       sOut.nBuf = 0;
       if( rc!=SQLITE_OK ) goto finished_invert;
@@ -4895,7 +4897,7 @@ static int sessionChangegroupOutput(
         sessionAppendByte(&buf, p->op, &rc);
         sessionAppendByte(&buf, p->bIndirect, &rc);
         sessionAppendBlob(&buf, p->aRecord, p->nRecord, &rc);
-        if( rc==SQLITE_OK && xOutput && buf.nBuf>=SESSIONS_STRM_CHUNK_SIZE ){
+        if( rc==SQLITE_OK && xOutput && buf.nBuf>=sessions_strm_chunk_size ){
           rc = xOutput(pOut, buf.aBuf, buf.nBuf);
           buf.nBuf = 0;
         }
@@ -5291,7 +5293,7 @@ static int sessionRebase(
       sessionAppendByte(&sOut, pIter->bIndirect, &rc);
       sessionAppendBlob(&sOut, aRec, nRec, &rc);
     }
-    if( rc==SQLITE_OK && xOutput && sOut.nBuf>SESSIONS_STRM_CHUNK_SIZE ){
+    if( rc==SQLITE_OK && xOutput && sOut.nBuf>sessions_strm_chunk_size ){
       rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
       sOut.nBuf = 0;
     }
@@ -5402,4 +5404,25 @@ void sqlite3rebaser_delete(sqlite3_rebaser *p){
   }
 }
 
+/* 
+** Global configuration
+*/
+int sqlite3session_config(int op, void *pArg){
+  int rc = SQLITE_OK;
+  switch( op ){
+    case SQLITE_SESSION_CONFIG_STRMSIZE: {
+      int *pInt = (int*)pArg;
+      if( *pInt>0 ){
+        sessions_strm_chunk_size = *pInt;
+      }
+      *pInt = sessions_strm_chunk_size;
+      break;
+    }
+    default:
+      rc = SQLITE_MISUSE;
+      break;
+  }
+  return rc;
+}
+
 #endif /* SQLITE_ENABLE_SESSION && SQLITE_ENABLE_PREUPDATE_HOOK */
diff --git a/ext/session/sqlite3session.h b/ext/session/sqlite3session.h
index b9303635e7..3d1df429e3 100644
--- a/ext/session/sqlite3session.h
+++ b/ext/session/sqlite3session.h
@@ -1610,6 +1610,45 @@ int sqlite3rebaser_rebase_strm(
   void *pOut
 );
 
+/*
+** CAPI3REF: Configure global parameters
+**
+** The sqlite3session_config() interface is used to make global configuration
+** changes to the sessions module in order to tune it to the specific needs 
+** of the application.
+**
+** The sqlite3session_config() interface is not threadsafe. If it is invoked
+** while any other thread is inside any other sessions method then the
+** results are undefined. Furthermore, if it is invoked after any sessions
+** related objects have been created, the results are also undefined. 
+**
+** The first argument to the sqlite3session_config() function must be one
+** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The 
+** interpretation of the (void*) value passed as the second parameter and
+** the effect of calling this function depends on the value of the first
+** parameter.
+**
+** <dl>
+** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
+**    By default, the sessions module streaming interfaces attempt to input
+**    and output data in approximately 1 KiB chunks. This operand may be used
+**    to set and query the value of this configuration setting. The pointer
+**    passed as the second argument must point to a value of type (int).
+**    If this value is greater than 0, it is used as the new streaming data
+**    chunk size for both input and output. Before returning, the (int) value
+**    pointed to by pArg is set to the final value of the streaming interface
+**    chunk size.
+** </dl>
+**
+** This function returns SQLITE_OK if successful, or an SQLite error code
+** otherwise.
+*/
+int sqlite3session_config(int op, void *pArg);
+
+/*
+** CAPI3REF: Values for sqlite3session_config().
+*/
+#define SQLITE_SESSION_CONFIG_STRMSIZE 1
 
 /*
 ** Make sure we can call this stuff from C++.
diff --git a/ext/session/test_session.c b/ext/session/test_session.c
index 016050fdba..1e76616cbb 100644
--- a/ext/session/test_session.c
+++ b/ext/session/test_session.c
@@ -1239,6 +1239,45 @@ static int SQLITE_TCLAPI test_sqlite3rebaser_create(
   return TCL_OK;
 }
 
+/*
+** tclcmd: sqlite3rebaser_configure OP VALUE
+*/
+static int SQLITE_TCLAPI test_sqlite3session_config(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  struct ConfigOpt {
+    const char *zSub;
+    int op;
+  } aSub[] = {
+    { "strm_size",    SQLITE_SESSION_CONFIG_STRMSIZE },
+    { "invalid",      0 },
+    { 0 }
+  };
+  int rc;
+  int iSub;
+  int iVal;
+
+  if( objc!=3 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "OP VALUE");
+    return SQLITE_ERROR;
+  }
+  rc = Tcl_GetIndexFromObjStruct(interp, 
+      objv[1], aSub, sizeof(aSub[0]), "sub-command", 0, &iSub
+  );
+  if( rc!=TCL_OK ) return rc;
+  if( Tcl_GetIntFromObj(interp, objv[2], &iVal) ) return TCL_ERROR;
+
+  rc = sqlite3session_config(aSub[iSub].op, (void*)&iVal);
+  if( rc!=SQLITE_OK ){
+    return test_session_error(interp, rc, 0);
+  }
+  Tcl_SetObjResult(interp, Tcl_NewIntObj(iVal));
+  return TCL_OK;
+}
+
 int TestSession_Init(Tcl_Interp *interp){
   struct Cmd {
     const char *zCmd;
@@ -1254,6 +1293,7 @@ int TestSession_Init(Tcl_Interp *interp){
       test_sqlite3changeset_apply_replace_all },
     { "sql_exec_changeset", test_sql_exec_changeset },
     { "sqlite3rebaser_create", test_sqlite3rebaser_create },
+    { "sqlite3session_config", test_sqlite3session_config },
   };
   int i;
 
diff --git a/manifest b/manifest
index a7604adb25..5268fa17f5 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Prevent\san\s==\sconstraint\sspecified\susing\sthe\stable-valued-function\sargument\nsyntax\sfrom\sbeing\sused\sto\soptimize\sany\sscan\snot\srelated\sto\sthe\svirtual\stable\nfor\swhich\sit\swas\sspecified\sas\san\sargument.
-D 2018-10-26T15:36:53.982
+C Add\sthe\ssqlite3session_config()\sinterface.\sFor\sconfiguring\sglobal\sparameters\nbelonging\sto\sthe\ssessions\smodule.
+D 2018-10-26T17:05:00.030
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in 01e95208a78b57d056131382c493c963518f36da4c42b12a97eb324401b3a334
@@ -391,7 +391,7 @@ F ext/rtree/util/randomshape.tcl 54ee03d0d4a1c621806f7f44d5b78d2db8fac26e0e8687c
 F ext/rtree/viewrtree.tcl eea6224b3553599ae665b239bd827e182b466024
 F ext/rtree/visual01.txt e9c2564083bcd30ec51b07f881bffbf0e12b50a3f6fced0c222c5c1d2f94ac66
 F ext/session/changeset.c 4ccbaa4531944c24584bf6a61ba3a39c62b6267a
-F ext/session/session1.test 4532116484f525110eb4cfff7030c59354c0cde9def4d109466b0df2b35ad5cc
+F ext/session/session1.test 0b2f88995832ea040ae8e83a1ad4afa99c00b85c779d213da73a95ea4113233e
 F ext/session/session2.test 284de45abae4cc1082bc52012ee81521d5ac58e0
 F ext/session/session3.test ce9ce3dfa489473987f899e9f6a0f2db9bde3479
 F ext/session/session4.test 6778997065b44d99c51ff9cece047ff9244a32856b328735ae27ddef68979c40
@@ -417,9 +417,9 @@ F ext/session/sessioninvert.test ae1a003a9ab1f8d64227dbb5c3a4c97e65b561b01e7b295
 F ext/session/sessionrebase.test 4e1bcfd26fd8ed8ac571746f56cceeb45184f4d65490ea0d405227cfc8a9cba8
 F ext/session/sessionstat1.test 41cd97c2e48619a41cdf8ae749e1b25f34719de638689221aa43971be693bf4e
 F ext/session/sessionwor.test 2f3744236dc8b170a695b7d8ddc8c743c7e79fdc
-F ext/session/sqlite3session.c 7b9ae0d7f3f89551c893ad5beafe831df1c097623f6abc983dad7b6dbca726cb
-F ext/session/sqlite3session.h 11f229ec3f123da40c31500b01a2f6807185293d9173a5e0aa5be42ad70ab85d
-F ext/session/test_session.c 4699405b2afcf6833c11358cdb9da50f8f5d2b7123f44b3e2cef1cfb88c9fa39
+F ext/session/sqlite3session.c 0119dac126fb2b4ca6bed53509071d87a7977f3e97a2f8b8fa13c6e57beb6f76
+F ext/session/sqlite3session.h 05351d2f50a1203fdffbeb590fdbbc796c9a6bfcd0c9b26cf6db3854e3eb4294
+F ext/session/test_session.c 98797aba475a799376c9a42214f2d1debf2d0c3cb657d9c8bbf4f70bf3fb4aec
 F ext/userauth/sqlite3userauth.h 7f3ea8c4686db8e40b0a0e7a8e0b00fac13aa7a3
 F ext/userauth/user-auth.txt e6641021a9210364665fe625d067617d03f27b04
 F ext/userauth/userauth.c f81aa5a3ecacf406f170c62a144405858f6f6de51dbdc0920134e629edbe2648
@@ -1772,7 +1772,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 5d5b596f152bb2781011a05f75f9e200774d4f69d648ef68de577b4ace973e07
-R 8af441be159a5306c3bcc729f277a8dc
+P 4d46685f282409f7154be288719cbea4b743d7ea5315a55a91462003497469f7
+R c10d7255298165478f73aa6752c71429
 U dan
-Z 7280881af13a5758968cff92a52a3f86
+Z 0397ec87e4a63dd314f7afa18223a9dc
diff --git a/manifest.uuid b/manifest.uuid
index 59f3e0c5b9..9c1c574c1c 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-4d46685f282409f7154be288719cbea4b743d7ea5315a55a91462003497469f7
\ No newline at end of file
+1e69f3ff057b0be27a9e79842de2485f8299799f309e89bfa7597dd688e0975b
\ No newline at end of file