// was:sqlite3BtreeInsert
public RC Insert(byte[] key, long nKey, byte[] data, int nData, int nZero, bool appendBiasRight, int seekResult)
{
var loc = seekResult; // -1: before desired location +1: after
var szNew = 0;
int idx;
var p = this.Tree;
var pBt = p.Shared;
int oldCell;
byte[] newCell = null;
if (this.State == CursorState.FAULT)
{
Debug.Assert(this.SkipNext != 0);
return((RC)this.SkipNext);
}
Debug.Assert(HoldsMutex());
Debug.Assert(this.Writeable && pBt.InTransaction == TRANS.WRITE && !pBt.ReadOnly);
Debug.Assert(p.hasSharedCacheTableLock(this.RootID, (this.KeyInfo != null), LOCK.WRITE));
// Assert that the caller has been consistent. If this cursor was opened expecting an index b-tree, then the caller should be inserting blob
// keys with no associated data. If the cursor was opened expecting an intkey table, the caller should be inserting integer keys with a
// blob of associated data.
Debug.Assert((key == null) == (this.KeyInfo == null));
// If this is an insert into a table b-tree, invalidate any incrblob cursors open on the row being replaced (assuming this is a replace
// operation - if it is not, the following is a no-op). */
if (this.KeyInfo == null)
{
Btree.invalidateIncrblobCursors(p, nKey, false);
}
// Save the positions of any other cursors open on this table.
// In some cases, the call to btreeMoveto() below is a no-op. For example, when inserting data into a table with auto-generated integer
// keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the integer key to use. It then calls this function to actually insert the
// data into the intkey B-Tree. In this case btreeMoveto() recognizes that the cursor is already where it needs to be and returns without
// doing any work. To avoid thwarting these optimizations, it is important not to clear the cursor here.
var rc = pBt.saveAllCursors(this.RootID, this);
if (rc != RC.OK)
{
return(rc);
}
if (loc == 0)
{
rc = BtreeMoveTo(key, nKey, appendBiasRight, ref loc);
if (rc != RC.OK)
{
return(rc);
}
}
Debug.Assert(this.State == CursorState.VALID || (this.State == CursorState.INVALID && loc != 0));
var pPage = this.Pages[this.PageID];
Debug.Assert(pPage.HasIntKey || nKey >= 0);
Debug.Assert(pPage.Leaf != 0 || !pPage.HasIntKey);
Btree.TRACE("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n", this.RootID, nKey, nData, pPage.ID, (loc == 0 ? "overwrite" : "new entry"));
Debug.Assert(pPage.HasInit);
pBt.allocateTempSpace();
newCell = pBt.pTmpSpace;
rc = pPage.fillInCell(newCell, key, nKey, data, nData, nZero, ref szNew);
if (rc != RC.OK)
{
goto end_insert;
}
Debug.Assert(szNew == pPage.cellSizePtr(newCell));
Debug.Assert(szNew <= Btree.MX_CELL_SIZE(pBt));
idx = this.PagesIndexs[this.PageID];
if (loc == 0)
{
ushort szOld;
Debug.Assert(idx < pPage.Cells);
rc = Pager.Write(pPage.DbPage);
if (rc != RC.OK)
{
goto end_insert;
}
oldCell = pPage.FindCell(idx);
if (0 == pPage.Leaf)
{
newCell[0] = pPage.Data[oldCell + 0];
newCell[1] = pPage.Data[oldCell + 1];
newCell[2] = pPage.Data[oldCell + 2];
newCell[3] = pPage.Data[oldCell + 3];
}
szOld = pPage.cellSizePtr(oldCell);
rc = pPage.clearCell(oldCell);
pPage.dropCell(idx, szOld, ref rc);
if (rc != RC.OK)
{
goto end_insert;
}
}
else if (loc < 0 && pPage.Cells > 0)
{
Debug.Assert(pPage.Leaf != 0);
idx = ++this.PagesIndexs[this.PageID];
}
else
{
Debug.Assert(pPage.Leaf != 0);
}
pPage.insertCell(idx, newCell, szNew, null, 0, ref rc);
Debug.Assert(rc != RC.OK || pPage.Cells > 0 || pPage.NOverflows > 0);
// If no error has occured and pPage has an overflow cell, call balance() to redistribute the cells within the tree. Since balance() may move
// the cursor, zero the BtCursor.info.nSize and BtCursor.validNKey variables.
// Previous versions of SQLite called moveToRoot() to move the cursor back to the root page as balance() used to invalidate the contents
// of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that, set the cursor state to "invalid". This makes common insert operations
// slightly faster.
// There is a subtle but important optimization here too. When inserting multiple records into an intkey b-tree using a single cursor (as can
// happen while processing an "INSERT INTO ... SELECT" statement), it is advantageous to leave the cursor pointing to the last entry in
// the b-tree if possible. If the cursor is left pointing to the last entry in the table, and the next row inserted has an integer key
// larger than the largest existing key, it is possible to insert the row without seeking the cursor. This can be a big performance boost.
this.Info.nSize = 0;
this.ValidNKey = false;
if (rc == RC.OK && pPage.NOverflows != 0)
{
rc = Balance();
// Must make sure nOverflow is reset to zero even if the balance() fails. Internal data structure corruption will result otherwise.
// Also, set the cursor state to invalid. This stops saveCursorPosition() from trying to save the current position of the cursor.
this.Pages[this.PageID].NOverflows = 0;
this.State = CursorState.INVALID;
}
Debug.Assert(this.Pages[this.PageID].NOverflows == 0);
end_insert:
return(rc);
}
internal RC lockBtree()
{
Debug.Assert(MutexEx.Held(this.Mutex));
Debug.Assert(this.Page1 == null);
var rc = this.Pager.SharedLock();
if (rc != RC.OK)
{
return(rc);
}
MemPage pPage1 = null; // Page 1 of the database file
rc = btreeGetPage(1, ref pPage1, 0);
if (rc != RC.OK)
{
return(rc);
}
// Do some checking to help insure the file we opened really is a valid database file.
Pgno nPageHeader; // Number of pages in the database according to hdr
var nPage = nPageHeader = ConvertEx.Get4(pPage1.Data, 28); // Number of pages in the database
Pgno nPageFile; // Number of pages in the database file
this.Pager.GetPageCount(out nPageFile);
if (nPage == 0 || ArrayEx.Compare(pPage1.Data, 24, pPage1.Data, 92, 4) != 0)
{
nPage = nPageFile;
}
if (nPage > 0)
{
var page1 = pPage1.Data;
rc = RC.NOTADB;
if (ArrayEx.Compare(page1, Btree.zMagicHeader, 16) != 0)
{
goto page1_init_failed;
}
#if SQLITE_OMIT_WAL
if (page1[18] > 1)
{
this.ReadOnly = true;
}
if (page1[19] > 1)
{
this.Schema.file_format = page1[19];
goto page1_init_failed;
}
#else
if (page1[18] > 2)
{
pBt.readOnly = true;
}
if (page1[19] > 2)
{
goto page1_init_failed;
}
/* If the write version is set to 2, this database should be accessed
** in WAL mode. If the log is not already open, open it now. Then
** return SQLITE_OK and return without populating BtShared.pPage1.
** The caller detects this and calls this function again. This is
** required as the version of page 1 currently in the page1 buffer
** may not be the latest version - there may be a newer one in the log
** file.
*/
if (page1[19] == 2 && pBt.doNotUseWAL == false)
{
int isOpen = 0;
rc = sqlite3PagerOpenWal(pBt.pPager, ref isOpen);
if (rc != SQLITE_OK)
{
goto page1_init_failed;
}
else if (isOpen == 0)
{
releasePage(pPage1);
return(SQLITE_OK);
}
rc = SQLITE_NOTADB;
}
#endif
// The maximum embedded fraction must be exactly 25%. And the minimum embedded fraction must be 12.5% for both leaf-data and non-leaf-data.
// The original design allowed these amounts to vary, but as of version 3.6.0, we require them to be fixed.
if (ArrayEx.Compare(page1, 21, "\x0040\x0020\x0020", 3) != 0) // "\100\040\040"
{
goto page1_init_failed;
}
var pageSize = (uint)((page1[16] << 8) | (page1[17] << 16));
if (((pageSize - 1) & pageSize) != 0 || pageSize > Pager.SQLITE_MAX_PAGE_SIZE || pageSize <= 256)
{
goto page1_init_failed;
}
Debug.Assert((pageSize & 7) == 0);
var usableSize = pageSize - page1[20];
if (pageSize != this.PageSize)
{
// After reading the first page of the database assuming a page size of BtShared.pageSize, we have discovered that the page-size is
// actually pageSize. Unlock the database, leave pBt.pPage1 at zero and return SQLITE_OK. The caller will call this function
// again with the correct page-size.
pPage1.releasePage();
this.UsableSize = usableSize;
this.PageSize = pageSize;
rc = this.Pager.SetPageSize(ref this.PageSize, (int)(pageSize - usableSize));
return(rc);
}
if ((this.DB.flags & sqlite3b.SQLITE.RecoveryMode) == 0 && nPage > nPageFile)
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto page1_init_failed;
}
if (usableSize < 480)
{
goto page1_init_failed;
}
this.PageSize = pageSize;
this.UsableSize = usableSize;
#if !SQLITE_OMIT_AUTOVACUUM
this.AutoVacuum = (ConvertEx.Get4(page1, 36 + 4 * 4) != 0);
this.IncrVacuum = (ConvertEx.Get4(page1, 36 + 7 * 4) != 0);
#endif
}
// maxLocal is the maximum amount of payload to store locally for a cell. Make sure it is small enough so that at least minFanout
// cells can will fit on one page. We assume a 10-byte page header. Besides the payload, the cell must store:
// 2-byte pointer to the cell
// 4-byte child pointer
// 9-byte nKey value
// 4-byte nData value
// 4-byte overflow page pointer
// So a cell consists of a 2-byte pointer, a header which is as much as 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow page pointer.
this.MaxLocal = (ushort)((this.UsableSize - 12) * 64 / 255 - 23);
this.MinLocal = (ushort)((this.UsableSize - 12) * 32 / 255 - 23);
this.MaxLeaf = (ushort)(this.UsableSize - 35);
this.MinLeaf = (ushort)((this.UsableSize - 12) * 32 / 255 - 23);
Debug.Assert(this.MaxLeaf + 23 <= Btree.MX_CELL_SIZE(this));
this.Page1 = pPage1;
this.Pages = nPage;
return(RC.OK);
page1_init_failed:
pPage1.releasePage();
this.Page1 = null;
return(rc);
}
// was:sqlite3BtreeDelete
public RC Delete()
{
MemPage pPage; // Page to delete cell from
int pCell; // Pointer to cell to delete
int iCellIdx; // Index of cell to delete
int iCellDepth; // Depth of node containing pCell
var p = this.Tree;
var pBt = p.Shared;
Debug.Assert(HoldsMutex());
Debug.Assert(pBt.InTransaction == TRANS.WRITE);
Debug.Assert(!pBt.ReadOnly);
Debug.Assert(this.Writeable);
Debug.Assert(p.hasSharedCacheTableLock(this.RootID, (this.KeyInfo != null), LOCK.WRITE));
Debug.Assert(!p.hasReadConflicts(this.RootID));
if (Check.NEVER(this.PagesIndexs[this.PageID] >= this.Pages[this.PageID].Cells) || Check.NEVER(this.State != CursorState.VALID))
{
return(RC.ERROR);
}
// If this is a delete operation to remove a row from a table b-tree, invalidate any incrblob cursors open on the row being deleted.
if (this.KeyInfo == null)
{
Btree.invalidateIncrblobCursors(p, this.Info.nKey, false);
}
iCellDepth = this.PageID;
iCellIdx = this.PagesIndexs[iCellDepth];
pPage = this.Pages[iCellDepth];
pCell = pPage.FindCell(iCellIdx);
// If the page containing the entry to delete is not a leaf page, move the cursor to the largest entry in the tree that is smaller than
// the entry being deleted. This cell will replace the cell being deleted from the internal node. The 'previous' entry is used for this instead
// of the 'next' entry, as the previous entry is always a part of the sub-tree headed by the child page of the cell being deleted. This makes
// balancing the tree following the delete operation easier.
RC rc;
if (pPage.Leaf == 0)
{
var notUsed = 0;
rc = MovePrevious(ref notUsed);
if (rc != RC.OK)
{
return(rc);
}
}
// Save the positions of any other cursors open on this table before making any modifications. Make the page containing the entry to be
// deleted writable. Then free any overflow pages associated with the entry and finally remove the cell itself from within the page.
rc = pBt.saveAllCursors(this.RootID, this);
if (rc != RC.OK)
{
return(rc);
}
rc = Pager.Write(pPage.DbPage);
if (rc != RC.OK)
{
return(rc);
}
rc = pPage.clearCell(pCell);
pPage.dropCell(iCellIdx, pPage.cellSizePtr(pCell), ref rc);
if (rc != RC.OK)
{
return(rc);
}
// If the cell deleted was not located on a leaf page, then the cursor is currently pointing to the largest entry in the sub-tree headed
// by the child-page of the cell that was just deleted from an internal node. The cell from the leaf node needs to be moved to the internal
// node to replace the deleted cell.
if (pPage.Leaf == 0)
{
var pLeaf = this.Pages[this.PageID];
int nCell;
var n = this.Pages[iCellDepth + 1].ID;
pCell = pLeaf.FindCell(pLeaf.Cells - 1);
nCell = pLeaf.cellSizePtr(pCell);
Debug.Assert(Btree.MX_CELL_SIZE(pBt) >= nCell);
rc = Pager.Write(pLeaf.DbPage);
var pNext_4 = MallocEx.sqlite3Malloc(nCell + 4);
Buffer.BlockCopy(pLeaf.Data, pCell - 4, pNext_4, 0, nCell + 4);
pPage.insertCell(iCellIdx, pNext_4, nCell + 4, null, n, ref rc);
pLeaf.dropCell(pLeaf.Cells - 1, nCell, ref rc);
if (rc != RC.OK)
{
return(rc);
}
}
// Balance the tree. If the entry deleted was located on a leaf page, then the cursor still points to that page. In this case the first
// call to balance() repairs the tree, and the if(...) condition is never true.
//
// Otherwise, if the entry deleted was on an internal node page, then pCur is pointing to the leaf page from which a cell was removed to
// replace the cell deleted from the internal node. This is slightly tricky as the leaf node may be underfull, and the internal node may
// be either under or overfull. In this case run the balancing algorithm on the leaf node first. If the balance proceeds far enough up the
// tree that we can be sure that any problem in the internal node has been corrected, so be it. Otherwise, after balancing the leaf node,
// walk the cursor up the tree to the internal node and balance it as well.
rc = Balance();
if (rc == RC.OK && this.PageID > iCellDepth)
{
while (this.PageID > iCellDepth)
{
this.Pages[this.PageID--].releasePage();
}
rc = Balance();
}
if (rc == RC.OK)
{
MoveToRoot();
}
return(rc);
}
