Use the sqlite3_blob interface for reading values from the %_node shadow

table in RTREE.  This is a work in progress.  There are still some minor
problems.

FossilOrigin-Name: fc4917d730b29b0bf60fea5e0166728635783e9c

ext/rtree/rtree.c

@@ -133,6 +133,9 @@ struct Rtree {
   RtreeNode *pDeleted;
   int iReinsertHeight;        /* Height of sub-trees Reinsert() has run on */
 
+  /* Blob I/O on xxx_node */
+  sqlite3_blob *pNodeBlob;
+
   /* Statements to read/write/delete a record from xxx_node */
   sqlite3_stmt *pReadNode;
   sqlite3_stmt *pWriteNode;
@@ -615,6 +618,16 @@ static RtreeNode *nodeNew(Rtree *pRtree, RtreeNode *pParent){
   return pNode;
 }
 
+/*
+** Clear the Rtree.pNodeBlob object
+*/
+static void nodeBlobReset(Rtree *pRtree){
+  if( pRtree->pNodeBlob ){
+    sqlite3_blob_close(pRtree->pNodeBlob);
+    pRtree->pNodeBlob = 0;
+  }
+}
+
 /*
 ** Obtain a reference to an r-tree node.
 */
@@ -624,9 +637,8 @@ static int nodeAcquire(
   RtreeNode *pParent,        /* Either the parent node or NULL */
   RtreeNode **ppNode         /* OUT: Acquired node */
 ){
-  int rc;
+  int rc = SQLITE_OK;
-  int rc2 = SQLITE_OK;
+  RtreeNode *pNode = 0;
-  RtreeNode *pNode;
 
   /* Check if the requested node is already in the hash table. If so,
   ** increase its reference count and return it.
@@ -642,28 +654,42 @@ static int nodeAcquire(
     return SQLITE_OK;
   }
 
-  sqlite3_bind_int64(pRtree->pReadNode, 1, iNode);
+  if( pRtree->pNodeBlob ){
-  rc = sqlite3_step(pRtree->pReadNode);
+    sqlite3_blob *pBlob = pRtree->pNodeBlob;
-  if( rc==SQLITE_ROW ){
+    pRtree->pNodeBlob = 0;
-    const u8 *zBlob = sqlite3_column_blob(pRtree->pReadNode, 0);
+    rc = sqlite3_blob_reopen(pBlob, iNode);
-    if( pRtree->iNodeSize==sqlite3_column_bytes(pRtree->pReadNode, 0) ){
+    pRtree->pNodeBlob = pBlob;
-      pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode)+pRtree->iNodeSize);
+    if( rc ){
-      if( !pNode ){
+      nodeBlobReset(pRtree);
-        rc2 = SQLITE_NOMEM;
+      if( rc==SQLITE_NOMEM ) return rc;
-      }else{
+    }
-        pNode->pParent = pParent;
+  }
-        pNode->zData = (u8 *)&pNode[1];
+  if( pRtree->pNodeBlob==0 ){
-        pNode->nRef = 1;
+    char *zTab = sqlite3_mprintf("%s_node", pRtree->zName);
-        pNode->iNode = iNode;
+    if( zTab==0 ) return SQLITE_NOMEM;
-        pNode->isDirty = 0;
+    rc = sqlite3_blob_open(pRtree->db, pRtree->zDb, zTab, "data", iNode, 0,
-        pNode->pNext = 0;
+                           &pRtree->pNodeBlob);
-        memcpy(pNode->zData, zBlob, pRtree->iNodeSize);
+    sqlite3_free(zTab);
-        nodeReference(pParent);
+  }
-      }
+  if( rc ){
+    nodeBlobReset(pRtree);
+    *ppNode = 0;
+  }else if( pRtree->iNodeSize==sqlite3_blob_bytes(pRtree->pNodeBlob) ){
+    pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode)+pRtree->iNodeSize);
+    if( !pNode ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pNode->pParent = pParent;
+      pNode->zData = (u8 *)&pNode[1];
+      pNode->nRef = 1;
+      pNode->iNode = iNode;
+      pNode->isDirty = 0;
+      pNode->pNext = 0;
+      rc = sqlite3_blob_read(pRtree->pNodeBlob, pNode->zData,
+                             pRtree->iNodeSize, 0);
+      nodeReference(pParent);
     }
   }
-  rc = sqlite3_reset(pRtree->pReadNode);
-  if( rc==SQLITE_OK ) rc = rc2;
 
   /* If the root node was just loaded, set pRtree->iDepth to the height
   ** of the r-tree structure. A height of zero means all data is stored on
@@ -909,6 +935,7 @@ static void rtreeReference(Rtree *pRtree){
 static void rtreeRelease(Rtree *pRtree){
   pRtree->nBusy--;
   if( pRtree->nBusy==0 ){
+    nodeBlobReset(pRtree);
     sqlite3_finalize(pRtree->pReadNode);
     sqlite3_finalize(pRtree->pWriteNode);
     sqlite3_finalize(pRtree->pDeleteNode);
@@ -947,6 +974,7 @@ static int rtreeDestroy(sqlite3_vtab *pVtab){
   if( !zCreate ){
     rc = SQLITE_NOMEM;
   }else{
+    nodeBlobReset(pRtree);
     rc = sqlite3_exec(pRtree->db, zCreate, 0, 0, 0);
     sqlite3_free(zCreate);
   }
@@ -3152,6 +3180,27 @@ constraint:
   return rc;
 }
 
+/*
+** Called when a transaction starts.
+** This is a no-op.  But the Virtual Table mechanism needs a method
+** here or else it will never call the xRollback and xCommit methods,
+** and those methods are necessary for clearing the sqlite3_blob object.
+*/
+static int rtreeBeginTransaction(sqlite3_vtab *pVtab){
+  (void)pVtab;
+  return SQLITE_OK;
+}
+
+/*
+** Called when a transaction completes (either by COMMIT or ROLLBACK).
+** The sqlite3_blob object should be released at this point.
+*/
+static int rtreeEndTransaction(sqlite3_vtab *pVtab){
+  Rtree *pRtree = (Rtree *)pVtab;
+  nodeBlobReset(pRtree);
+  return SQLITE_OK;
+}
+
 /*
 ** The xRename method for rtree module virtual tables.
 */
@@ -3173,6 +3222,7 @@ static int rtreeRename(sqlite3_vtab *pVtab, const char *zNewName){
   return rc;
 }
 
+
 /*
 ** This function populates the pRtree->nRowEst variable with an estimate
 ** of the number of rows in the virtual table. If possible, this is based
@@ -3232,15 +3282,15 @@ static sqlite3_module rtreeModule = {
   rtreeColumn,                /* xColumn - read data */
   rtreeRowid,                 /* xRowid - read data */
   rtreeUpdate,                /* xUpdate - write data */
-  0,                          /* xBegin - begin transaction */
+  rtreeBeginTransaction,      /* xBegin - begin transaction */
   0,                          /* xSync - sync transaction */
-  0,                          /* xCommit - commit transaction */
+  rtreeEndTransaction,        /* xCommit - commit transaction */
-  0,                          /* xRollback - rollback transaction */
+  rtreeEndTransaction,        /* xRollback - rollback transaction */
   0,                          /* xFindFunction - function overloading */
   rtreeRename,                /* xRename - rename the table */
   0,                          /* xSavepoint */
   0,                          /* xRelease */
-  0                           /* xRollbackTo */
+  0,                          /* xRollbackTo */
 };
 
 static int rtreeSqlInit(
@@ -3440,7 +3490,7 @@ static int rtreeInit(
   pRtree->zDb = (char *)&pRtree[1];
   pRtree->zName = &pRtree->zDb[nDb+1];
   pRtree->nDim = (u8)((argc-4)/2);
-  pRtree->nDim2 = argc - 4;
+  pRtree->nDim2 = pRtree->nDim*2;
   pRtree->nBytesPerCell = 8 + pRtree->nDim2*4;
   pRtree->eCoordType = (u8)eCoordType;
   memcpy(pRtree->zDb, argv[1], nDb);

manifest

@@ -1,5 +1,5 @@
-C This\sis\san\sexperimental\spatch\sthat\sensures\sthat\sall\scursors\shave\stheir\sposition\nsaved\sprior\sto\sstarting\sa\sROLLBACK\sTO.
+C Use\sthe\ssqlite3_blob\sinterface\sfor\sreading\svalues\sfrom\sthe\s%_node\sshadow\ntable\sin\sRTREE.\s\sThis\sis\sa\swork\sin\sprogress.\s\sThere\sare\sstill\ssome\sminor\nproblems.
-D 2017-02-02T00:46:55.000
+D 2017-02-02T02:28:45.543
 F Makefile.in 5f415e7867296d678fed2e6779aea10c1318b4bc
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc ba953c8921fc7e18333f61898007206de7e23964
@@ -264,7 +264,7 @@ F ext/rbu/sqlite3rbu.c bb0de6cdbdb14a7d55a097238a434b7e99caf318
 F ext/rbu/sqlite3rbu.h 6fb6294c34a9ca93b5894a33bca530c6f08decba
 F ext/rbu/test_rbu.c 5aa22616afac6f71ebd3d9bc9bf1006cfabcca88
 F ext/rtree/README 6315c0d73ebf0ec40dedb5aa0e942bc8b54e3761
-F ext/rtree/rtree.c 70f2488eef5c04dccf15a52cbd4961492124f825
+F ext/rtree/rtree.c 73c4308585c47a7500b9e98617e45a62f8564ddb
 F ext/rtree/rtree.h 834dbcb82dc85b2481cde6a07cdadfddc99e9b9e
 F ext/rtree/rtree1.test 42dadfc7b44a436cd74a1bebc0b9b689e4eaf7ec
 F ext/rtree/rtree2.test acbb3a4ce0f4fbc2c304d2b4b784cfa161856bba
@@ -1552,10 +1552,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 0c66cf0f0a9ada2ddcb8d61001ef791b86226416
+P 01d97e5b6502b1811b52a681f445e1aaae6c0ee6
-R 329580c21139f900f64001f6acfc9557
+R 79c2c34c9473af6d4e0161547969b398
-T *branch * savepoint-rollback
+T *branch * rtree-sqlite3_blob
-T *sym-savepoint-rollback *
+T *sym-rtree-sqlite3_blob *
-T -sym-trunk *
+T -sym-savepoint-rollback *
 U drh
-Z 5087946e64391fb6ac59f69d722efdd6
+Z fc394298cc4191cf41d9c752fa550c9c

manifest.uuid

@@ -1 +1 @@
-01d97e5b6502b1811b52a681f445e1aaae6c0ee6
+fc4917d730b29b0bf60fea5e0166728635783e9c