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Overview
| Comment: | Early detection of implausibly sized records to avoid unnecessary large memory allocations. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
2c8769c69f301307db6663adb8b7c0b8 |
| User & Date: | drh 2019-02-04 21:10:24 |
Context
|
2019-02-05
| ||
| 08:55 | Update test file "resetdb.test" so that it works with the "prepare" permutation. check-in: 95d338124b user: dan tags: trunk | |
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2019-02-04
| ||
| 21:10 | Early detection of implausibly sized records to avoid unnecessary large memory allocations. check-in: 2c8769c69f user: drh tags: trunk | |
| 19:52 | Mention the new -memtrace command-line option in the -help output of the CLI. check-in: ada91aefe3 user: drh tags: trunk | |
Changes
Changes to src/btree.c.
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*/
u32 sqlite3BtreePayloadSize(BtCursor *pCur){
assert( cursorHoldsMutex(pCur) );
assert( pCur->eState==CURSOR_VALID );
getCellInfo(pCur);
return pCur->info.nPayload;
}
/*
** Given the page number of an overflow page in the database (parameter
** ovfl), this function finds the page number of the next page in the
** linked list of overflow pages. If possible, it uses the auto-vacuum
** pointer-map data instead of reading the content of page ovfl to do so.
**
|
> > > > > > > > > > > > > > > > > > > |
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*/
u32 sqlite3BtreePayloadSize(BtCursor *pCur){
assert( cursorHoldsMutex(pCur) );
assert( pCur->eState==CURSOR_VALID );
getCellInfo(pCur);
return pCur->info.nPayload;
}
/*
** Return an upper bound on the size of any record for the table
** that the cursor is pointing into.
**
** This is an optimization. Everything will still work if this
** routine always returns 2147483647 (which is the largest record
** that SQLite can handle) or more. But returning a smaller value might
** prevent large memory allocations when trying to interpret a
** corrupt datrabase.
**
** The current implementation merely returns the size of the underlying
** database file.
*/
sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor *pCur){
assert( cursorHoldsMutex(pCur) );
assert( pCur->eState==CURSOR_VALID );
return pCur->pBt->pageSize * (sqlite3_int64)pCur->pBt->nPage;
}
/*
** Given the page number of an overflow page in the database (parameter
** ovfl), this function finds the page number of the next page in the
** linked list of overflow pages. If possible, it uses the auto-vacuum
** pointer-map data instead of reading the content of page ovfl to do so.
**
|
Changes to src/btree.h.
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i64 sqlite3BtreeIntegerKey(BtCursor*); #ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC i64 sqlite3BtreeOffset(BtCursor*); #endif int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*); const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt); u32 sqlite3BtreePayloadSize(BtCursor*); char *sqlite3BtreeIntegrityCheck(Btree*, int *aRoot, int nRoot, int, int*); struct Pager *sqlite3BtreePager(Btree*); i64 sqlite3BtreeRowCountEst(BtCursor*); #ifndef SQLITE_OMIT_INCRBLOB int sqlite3BtreePayloadChecked(BtCursor*, u32 offset, u32 amt, void*); |
> |
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i64 sqlite3BtreeIntegerKey(BtCursor*);
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
i64 sqlite3BtreeOffset(BtCursor*);
#endif
int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*);
const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt);
u32 sqlite3BtreePayloadSize(BtCursor*);
sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*);
char *sqlite3BtreeIntegrityCheck(Btree*, int *aRoot, int nRoot, int, int*);
struct Pager *sqlite3BtreePager(Btree*);
i64 sqlite3BtreeRowCountEst(BtCursor*);
#ifndef SQLITE_OMIT_INCRBLOB
int sqlite3BtreePayloadChecked(BtCursor*, u32 offset, u32 amt, void*);
|
Changes to src/vdbemem.c.
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BtCursor *pCur, /* Cursor pointing at record to retrieve. */
u32 offset, /* Offset from the start of data to return bytes from. */
u32 amt, /* Number of bytes to return. */
Mem *pMem /* OUT: Return data in this Mem structure. */
){
int rc;
pMem->flags = MEM_Null;
if( SQLITE_OK==(rc = sqlite3VdbeMemClearAndResize(pMem, amt+1)) ){
rc = sqlite3BtreePayload(pCur, offset, amt, pMem->z);
if( rc==SQLITE_OK ){
pMem->z[amt] = 0; /* Overrun area used when reading malformed records */
pMem->flags = MEM_Blob;
pMem->n = (int)amt;
}else{
|
> > > |
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BtCursor *pCur, /* Cursor pointing at record to retrieve. */
u32 offset, /* Offset from the start of data to return bytes from. */
u32 amt, /* Number of bytes to return. */
Mem *pMem /* OUT: Return data in this Mem structure. */
){
int rc;
pMem->flags = MEM_Null;
if( sqlite3BtreeMaxRecordSize(pCur)<offset+amt ){
return SQLITE_CORRUPT_BKPT;
}
if( SQLITE_OK==(rc = sqlite3VdbeMemClearAndResize(pMem, amt+1)) ){
rc = sqlite3BtreePayload(pCur, offset, amt, pMem->z);
if( rc==SQLITE_OK ){
pMem->z[amt] = 0; /* Overrun area used when reading malformed records */
pMem->flags = MEM_Blob;
pMem->n = (int)amt;
}else{
|