we try to create a local dev environment on my OSX Sierra so I can debug sqlite3. Tried with Eclipse Neo on my OSX Sierra with the following setup, no luck.
https://www.ics.uci.edu/~pattis/common/handouts/macmingweclipse/allexperimental/mac-gdb-install.html
Finally, made it work with xcode. folder sqlitetest containers the xcode project for this. download latest xcode and import the project, you can setup breakpoints and step through.
we use chinook.db from sqlite tutorial.
the current working dir in mac is somewhere under $HOME/Library/Developer/Xcode/DerivedData/sqlitetest-fuhccdahfchkkphkkellpeacfgxk/Build/Products/Debug. It is not at the project home. wierd.
there 4 types of btree pages, namely,
table btree interior page with cell [left-child-page-no, varint-key]
table btree leaf page with cell [varint-payload-size, rowId, payload-header(col schema), row-content]
index btree interior page with cell
index btree leaf page with cell
sqlite is using b+ tree where all row data is stored in leaf page cell, and table page interior cells only store [left-child-page, key].
Cells in page are sorted by their keys. 2 bytes cell pointer stores offset of cell content area from the end of page.
When insert new row, append row data, and re-arrange cell idx array with
static int editPage(
MemPage *pPg, /* Edit this page */
int iOld, /* Index of first cell currently on page */
int iNew, /* Index of new first cell on page */
int nNew, /* Final number of cells on page */
CellArray *pCArray /* Array of cells and sizes */
){
memmove(&pCellptr[nAdd*2], pCellptr, nCell*2);
}
The other path is balance btree node using balance_quick, balance_nonroot, and balance_deeper.
Simple example of balance_quick.
static int balance_quick(MemPage *pParent, MemPage *pPage, u8 *pSpace){
rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
// find divider cell [left-child-page-no, key] to insert into parent interior page,
pCell = findCell(pPage, pPage->nCell-1);
// copy key into pOut.
while( ((*(pOut++) = *(pCell++))&0x80) && pCell<pStop );
// insert divide cell into parent
insertCell(pParent, pParent->nCell, pSpace, (int)(pOut-pSpace),
0, pPage->pgno, &rc);
/* Set the right-child pointer of pParent to point to the new page. */
put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew);
/* Release the reference to the new page. */
releasePage(pNew);
}
https://www.sqlite.org/fileformat2.html https://digitalforensicforest.wordpress.com/2015/07/27/sqlite-data-carving-a-way-to-trace/ http://forensicsfromthesausagefactory.blogspot.com/2011/05/analysis-of-record-structure-within.html
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