dbtuxnode.cpp

mysql-5.0.22.tar.gz源码包

void
Dbtux::nodePushDownScans(NodeHandle& node, unsigned pos)
{
  const unsigned occup = node.getOccup();
  ScanOpPtr scanPtr;
  scanPtr.i = node.getNodeScan();
  do {
    jam();
    c_scanOpPool.getPtr(scanPtr);
    TreePos& scanPos = scanPtr.p->m_scanPos;
    ndbrequire(scanPos.m_loc == node.m_loc && scanPos.m_pos < occup);
    // handled before
    ndbrequire(scanPos.m_pos != 0);
    if (scanPos.m_pos <= pos) {
      jam();
#ifdef VM_TRACE
      if (debugFlags & DebugScan) {
        debugOut << "Fix scan " << scanPtr.i << " " << *scanPtr.p << endl;
        debugOut << "At pushDown pos=" << pos << " " << node << endl;
      }
#endif
      scanPos.m_pos--;
    }
    scanPtr.i = scanPtr.p->m_nodeScan;
  } while (scanPtr.i != RNIL);
}

/*
 * Remove and return entry at position.  Move entries less than the
 * removed one to the right.  Replace min entry by the input entry.
 * This is the opposite of nodePushDown.
 *
 *      X                        D
 *      v     ^                  ^
 *      A B C D E _ _  =>  X A B C E _ _
 *      0 1 2 3 4 5 6      0 1 2 3 4 5 6
 *
 * Move scans at removed entry and add scans at the new entry.
 */
void
Dbtux::nodePopUp(NodeHandle& node, unsigned pos, TreeEnt& ent, Uint32 scanList)
{
  Frag& frag = node.m_frag;
  TreeHead& tree = frag.m_tree;
  const unsigned occup = node.getOccup();
  ndbrequire(occup <= tree.m_maxOccup && pos < occup);
  if (node.getNodeScan() != RNIL) {
    // move scans whose entry disappears
    moveScanList(node, pos);
    // fix other scans
    if (node.getNodeScan() != RNIL)
      nodePopUpScans(node, pos);
  }
  // fix node
  TreeEnt* const entList = tree.getEntList(node.m_node);
  entList[occup] = entList[0];
  TreeEnt* const tmpList = entList + 1;
  TreeEnt newMin = ent;
  ent = tmpList[pos];
  for (unsigned i = pos; i > 0; i--) {
    jam();
    tmpList[i] = tmpList[i - 1];
  }
  tmpList[0] = newMin;
  entList[0] = entList[occup];
  // add scans
  if (scanList != RNIL)
    addScanList(node, 0, scanList);
  // fix prefix
  if (true)
    setNodePref(node);
}

void
Dbtux::nodePopUpScans(NodeHandle& node, unsigned pos)
{
  const unsigned occup = node.getOccup();
  ScanOpPtr scanPtr;
  scanPtr.i = node.getNodeScan();
  do {
    jam();
    c_scanOpPool.getPtr(scanPtr);
    TreePos& scanPos = scanPtr.p->m_scanPos;
    ndbrequire(scanPos.m_loc == node.m_loc && scanPos.m_pos < occup);
    ndbrequire(scanPos.m_pos != pos);
    if (scanPos.m_pos < pos) {
      jam();
#ifdef VM_TRACE
      if (debugFlags & DebugScan) {
        debugOut << "Fix scan " << scanPtr.i << " " << *scanPtr.p << endl;
        debugOut << "At popUp pos=" << pos << " " << node << endl;
      }
#endif
      scanPos.m_pos++;
    }
    scanPtr.i = scanPtr.p->m_nodeScan;
  } while (scanPtr.i != RNIL);
}

/*
 * Move number of entries from another node to this node before the min
 * (i=0) or after the max (i=1).  Expensive but not often used.
 */
void
Dbtux::nodeSlide(NodeHandle& dstNode, NodeHandle& srcNode, unsigned cnt, unsigned i)
{
  Frag& frag = dstNode.m_frag;
  TreeHead& tree = frag.m_tree;
  ndbrequire(i <= 1);
  while (cnt != 0) {
    TreeEnt ent;
    Uint32 scanList = RNIL;
    nodePopDown(srcNode, i == 0 ? srcNode.getOccup() - 1 : 0, ent, &scanList);
    nodePushUp(dstNode, i == 0 ? 0 : dstNode.getOccup(), ent, scanList);
    cnt--;
  }
}

// scans linked to node


/*
 * Add list of scans to node at given position.
 */
void
Dbtux::addScanList(NodeHandle& node, unsigned pos, Uint32 scanList)
{
  ScanOpPtr scanPtr;
  scanPtr.i = scanList;
  do {
    jam();
    c_scanOpPool.getPtr(scanPtr);
#ifdef VM_TRACE
      if (debugFlags & DebugScan) {
        debugOut << "Add scan " << scanPtr.i << " " << *scanPtr.p << endl;
        debugOut << "To pos=" << pos << " " << node << endl;
      }
#endif
    const Uint32 nextPtrI = scanPtr.p->m_nodeScan;
    scanPtr.p->m_nodeScan = RNIL;
    linkScan(node, scanPtr);
    TreePos& scanPos = scanPtr.p->m_scanPos;
    // set position but leave direction alone
    scanPos.m_loc = node.m_loc;
    scanPos.m_pos = pos;
    scanPtr.i = nextPtrI;
  } while (scanPtr.i != RNIL);
}

/*
 * Remove list of scans from node at given position.  The return
 * location must point to existing list (in fact RNIL always).
 */
void
Dbtux::removeScanList(NodeHandle& node, unsigned pos, Uint32& scanList)
{
  ScanOpPtr scanPtr;
  scanPtr.i = node.getNodeScan();
  do {
    jam();
    c_scanOpPool.getPtr(scanPtr);
    const Uint32 nextPtrI = scanPtr.p->m_nodeScan;
    TreePos& scanPos = scanPtr.p->m_scanPos;
    ndbrequire(scanPos.m_loc == node.m_loc);
    if (scanPos.m_pos == pos) {
      jam();
#ifdef VM_TRACE
      if (debugFlags & DebugScan) {
        debugOut << "Remove scan " << scanPtr.i << " " << *scanPtr.p << endl;
        debugOut << "Fron pos=" << pos << " " << node << endl;
      }
#endif
      unlinkScan(node, scanPtr);
      scanPtr.p->m_nodeScan = scanList;
      scanList = scanPtr.i;
      // unset position but leave direction alone
      scanPos.m_loc = NullTupLoc;
      scanPos.m_pos = ZNIL;
    }
    scanPtr.i = nextPtrI;
  } while (scanPtr.i != RNIL);
}

/*
 * Move list of scans away from entry about to be removed.  Uses scan
 * method scanNext().
 */
void
Dbtux::moveScanList(NodeHandle& node, unsigned pos)
{
  ScanOpPtr scanPtr;
  scanPtr.i = node.getNodeScan();
  do {
    jam();
    c_scanOpPool.getPtr(scanPtr);
    TreePos& scanPos = scanPtr.p->m_scanPos;
    const Uint32 nextPtrI = scanPtr.p->m_nodeScan;
    ndbrequire(scanPos.m_loc == node.m_loc);
    if (scanPos.m_pos == pos) {
      jam();
#ifdef VM_TRACE
      if (debugFlags & DebugScan) {
        debugOut << "Move scan " << scanPtr.i << " " << *scanPtr.p << endl;
        debugOut << "At pos=" << pos << " " << node << endl;
      }
#endif
      scanNext(scanPtr, true);
      ndbrequire(! (scanPos.m_loc == node.m_loc && scanPos.m_pos == pos));
    }
    scanPtr.i = nextPtrI;
  } while (scanPtr.i != RNIL);
}

/*
 * Link scan to the list under the node.  The list is single-linked and
 * ordering does not matter.
 */
void
Dbtux::linkScan(NodeHandle& node, ScanOpPtr scanPtr)
{
#ifdef VM_TRACE
  if (debugFlags & DebugScan) {
    debugOut << "Link scan " << scanPtr.i << " " << *scanPtr.p << endl;
    debugOut << "To node " << node << endl;
  }
#endif
  ndbrequire(! islinkScan(node, scanPtr) && scanPtr.p->m_nodeScan == RNIL);
  scanPtr.p->m_nodeScan = node.getNodeScan();
  node.setNodeScan(scanPtr.i);
}

/*
 * Unlink a scan from the list under the node.
 */
void
Dbtux::unlinkScan(NodeHandle& node, ScanOpPtr scanPtr)
{
#ifdef VM_TRACE
  if (debugFlags & DebugScan) {
    debugOut << "Unlink scan " << scanPtr.i << " " << *scanPtr.p << endl;
    debugOut << "From node " << node << endl;
  }
#endif
  ScanOpPtr currPtr;
  currPtr.i = node.getNodeScan();
  ScanOpPtr prevPtr;
  prevPtr.i = RNIL;
  while (true) {
    jam();
    c_scanOpPool.getPtr(currPtr);
    Uint32 nextPtrI = currPtr.p->m_nodeScan;
    if (currPtr.i == scanPtr.i) {
      jam();
      if (prevPtr.i == RNIL) {
        node.setNodeScan(nextPtrI);
      } else {
        jam();
        prevPtr.p->m_nodeScan = nextPtrI;
      }
      scanPtr.p->m_nodeScan = RNIL;
      // check for duplicates
      ndbrequire(! islinkScan(node, scanPtr));
      return;
    }
    prevPtr = currPtr;
    currPtr.i = nextPtrI;
  }
}

/*
 * Check if a scan is linked to this node.  Only for ndbrequire.
 */
bool
Dbtux::islinkScan(NodeHandle& node, ScanOpPtr scanPtr)
{
  ScanOpPtr currPtr;
  currPtr.i = node.getNodeScan();
  while (currPtr.i != RNIL) {
    jam();
    c_scanOpPool.getPtr(currPtr);
    if (currPtr.i == scanPtr.i) {
      jam();
      return true;
    }
    currPtr.i = currPtr.p->m_nodeScan;
  }
  return false;
}

void
Dbtux::NodeHandle::progError(int line, int cause, const char* file)
{
  ErrorReporter::handleAssert("Dbtux::NodeHandle: assert failed", file, line);
}