/*
** Parameter zSrcData points to a buffer containing the data for
** page iSrcPg from the source database. Copy this data into the
** destination database.
*/
static int backupOnePage(sqlite3_backup *p, Pgno iSrcPg, const u8 *zSrcData){
Pager * const pDestPager = sqlite3BtreePager(p->pDest);
const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc);
int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest);
const int nCopy = MIN(nSrcPgsz, nDestPgsz);
const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz;
int rc = SQLITE_OK;
i64 iOff;
assert( p->bDestLocked );
assert( !isFatalError(p->rc) );
assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) );
assert( zSrcData );
/* Catch the case where the destination is an in-memory database and the
** page sizes of the source and destination differ.
*/
if( nSrcPgsz!=nDestPgsz && sqlite3PagerIsMemdb(sqlite3BtreePager(p->pDest)) ){
rc = SQLITE_READONLY;
}
/* This loop runs once for each destination page spanned by the source
** page. For each iteration, variable iOff is set to the byte offset
** of the destination page.
*/
for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){
DbPage *pDestPg = 0;
Pgno iDest = (Pgno)(iOff/nDestPgsz)+1;
if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue;
if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg))
&& SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg))
){
const u8 *zIn = &zSrcData[iOff%nSrcPgsz];
u8 *zDestData = sqlite3PagerGetData(pDestPg);
u8 *zOut = &zDestData[iOff%nDestPgsz];
/* Copy the data from the source page into the destination page.
** Then clear the Btree layer MemPage.isInit flag. Both this module
** and the pager code use this trick (clearing the first byte
** of the page 'extra' space to invalidate the Btree layers
** cached parse of the page). MemPage.isInit is marked
** "MUST BE FIRST" for this purpose.
*/
memcpy(zOut, zIn, nCopy);
((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0;
}
sqlite3PagerUnref(pDestPg);
}
return rc;
}
/*
** Usage: btree_ismemdb ID
**
** Return true if the B-Tree is in-memory.
*/
static int btree_ismemdb(
void *NotUsed,
Tcl_Interp *interp, /* The TCL interpreter that invoked this command */
int argc, /* Number of arguments */
const char **argv /* Text of each argument */
){
Btree *pBt;
int res;
if( argc!=2 ){
Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
" ID\"", 0);
return TCL_ERROR;
}
pBt = sqlite3TestTextToPtr(argv[1]);
sqlite3_mutex_enter(pBt->db->mutex);
sqlite3BtreeEnter(pBt);
res = sqlite3PagerIsMemdb(sqlite3BtreePager(pBt));
sqlite3BtreeLeave(pBt);
sqlite3_mutex_leave(pBt->db->mutex);
Tcl_SetObjResult(interp, Tcl_NewBooleanObj(res));
return SQLITE_OK;
}
/* CHANGE 1 of 3: Add function parameter nRes */
SQLITE_PRIVATE int sqlite3RunVacuumForRekey(char **pzErrMsg, sqlite3 *db, int iDb, int nRes){
int rc = SQLITE_OK; /* Return code from service routines */
Btree *pMain; /* The database being vacuumed */
Btree *pTemp; /* The temporary database we vacuum into */
u16 saved_mDbFlags; /* Saved value of db->mDbFlags */
u32 saved_flags; /* Saved value of db->flags */
int saved_nChange; /* Saved value of db->nChange */
int saved_nTotalChange; /* Saved value of db->nTotalChange */
u8 saved_mTrace; /* Saved trace settings */
Db *pDb = 0; /* Database to detach at end of vacuum */
int isMemDb; /* True if vacuuming a :memory: database */
/* CHANGE 2 of 3: Do not define local variable nRes */
/*int nRes;*/ /* Bytes of reserved space at the end of each page */
int nDb; /* Number of attached databases */
const char *zDbMain; /* Schema name of database to vacuum */
if (!db->autoCommit) {
sqlite3SetString(pzErrMsg, db, "cannot VACUUM from within a transaction");
return SQLITE_ERROR;
}
if (db->nVdbeActive>1) {
sqlite3SetString(pzErrMsg, db, "cannot VACUUM - SQL statements in progress");
return SQLITE_ERROR;
}
/* Save the current value of the database flags so that it can be
** restored before returning. Then set the writable-schema flag, and
** disable CHECK and foreign key constraints. */
saved_flags = db->flags;
saved_mDbFlags = db->mDbFlags;
saved_nChange = db->nChange;
saved_nTotalChange = db->nTotalChange;
saved_mTrace = db->mTrace;
db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;
db->mDbFlags |= DBFLAG_PreferBuiltin | DBFLAG_Vacuum;
db->flags &= ~(SQLITE_ForeignKeys | SQLITE_ReverseOrder | SQLITE_CountRows);
db->mTrace = 0;
zDbMain = db->aDb[iDb].zDbSName;
pMain = db->aDb[iDb].pBt;
isMemDb = sqlite3PagerIsMemdb(sqlite3BtreePager(pMain));
/* Attach the temporary database as 'vacuum_db'. The synchronous pragma
** can be set to 'off' for this file, as it is not recovered if a crash
** occurs anyway. The integrity of the database is maintained by a
** (possibly synchronous) transaction opened on the main database before
** sqlite3BtreeCopyFile() is called.
**
** An optimisation would be to use a non-journaled pager.
** (Later:) I tried setting "PRAGMA vacuum_db.journal_mode=OFF" but
** that actually made the VACUUM run slower. Very little journalling
** actually occurs when doing a vacuum since the vacuum_db is initially
** empty. Only the journal header is written. Apparently it takes more
** time to parse and run the PRAGMA to turn journalling off than it does
** to write the journal header file.
*/
nDb = db->nDb;
rc = execSql(db, pzErrMsg, "ATTACH''AS vacuum_db");
if (rc != SQLITE_OK) goto end_of_vacuum;
assert((db->nDb - 1) == nDb);
pDb = &db->aDb[nDb];
assert(strcmp(pDb->zDbSName, "vacuum_db") == 0);
pTemp = pDb->pBt;
/* The call to execSql() to attach the temp database has left the file
** locked (as there was more than one active statement when the transaction
** to read the schema was concluded. Unlock it here so that this doesn't
** cause problems for the call to BtreeSetPageSize() below. */
sqlite3BtreeCommit(pTemp);
/* CHANGE 3 of 3: Do not call sqlite3BtreeGetOptimalReserve */
/* nRes = sqlite3BtreeGetOptimalReserve(pMain); */
/* A VACUUM cannot change the pagesize of an encrypted database. */
#ifdef SQLITE_HAS_CODEC
if (db->nextPagesize) {
extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*);
int nKey;
char *zKey;
sqlite3CodecGetKey(db, iDb, (void**)&zKey, &nKey);
if (nKey) db->nextPagesize = 0;
}
#endif
sqlite3BtreeSetCacheSize(pTemp, db->aDb[iDb].pSchema->cache_size);
sqlite3BtreeSetSpillSize(pTemp, sqlite3BtreeSetSpillSize(pMain, 0));
sqlite3BtreeSetPagerFlags(pTemp, PAGER_SYNCHRONOUS_OFF | PAGER_CACHESPILL);
/* Begin a transaction and take an exclusive lock on the main database
** file. This is done before the sqlite3BtreeGetPageSize(pMain) call below,
** to ensure that we do not try to change the page-size on a WAL database.
*/
rc = execSql(db, pzErrMsg, "BEGIN");
if (rc != SQLITE_OK) goto end_of_vacuum;
rc = sqlite3BtreeBeginTrans(pMain, 2);
if (rc != SQLITE_OK) goto end_of_vacuum;
/* Do not attempt to change the page size for a WAL database */
if (sqlite3PagerGetJournalMode(sqlite3BtreePager(pMain))
== PAGER_JOURNALMODE_WAL) {
db->nextPagesize = 0;
}
if (sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes, 0)
|| (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes, 0))
|| NEVER(db->mallocFailed)
) {
rc = SQLITE_NOMEM_BKPT;
goto end_of_vacuum;
}
#ifndef SQLITE_OMIT_AUTOVACUUM
sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac >= 0 ? db->nextAutovac :
sqlite3BtreeGetAutoVacuum(pMain));
#endif
/* Query the schema of the main database. Create a mirror schema
** in the temporary database.
*/
db->init.iDb = nDb; /* force new CREATE statements into vacuum_db */
rc = execSqlF(db, pzErrMsg,
"SELECT sql FROM \"%w\".sqlite_master"
" WHERE type='table'AND name<>'sqlite_sequence'"
" AND coalesce(rootpage,1)>0",
zDbMain
);
if (rc != SQLITE_OK) goto end_of_vacuum;
rc = execSqlF(db, pzErrMsg,
"SELECT sql FROM \"%w\".sqlite_master"
" WHERE type='index'",
zDbMain
);
if (rc != SQLITE_OK) goto end_of_vacuum;
db->init.iDb = 0;
/* Loop through the tables in the main database. For each, do
** an "INSERT INTO vacuum_db.xxx SELECT * FROM main.xxx;" to copy
** the contents to the temporary database.
*/
rc = execSqlF(db, pzErrMsg,
"SELECT'INSERT INTO vacuum_db.'||quote(name)"
"||' SELECT*FROM\"%w\".'||quote(name)"
"FROM vacuum_db.sqlite_master "
"WHERE type='table'AND coalesce(rootpage,1)>0",
zDbMain
);
assert((db->mDbFlags & DBFLAG_Vacuum) != 0);
db->mDbFlags &= ~DBFLAG_Vacuum;
if (rc != SQLITE_OK) goto end_of_vacuum;
/* Copy the triggers, views, and virtual tables from the main database
** over to the temporary database. None of these objects has any
** associated storage, so all we have to do is copy their entries
** from the SQLITE_MASTER table.
*/
rc = execSqlF(db, pzErrMsg,
"INSERT INTO vacuum_db.sqlite_master"
" SELECT*FROM \"%w\".sqlite_master"
" WHERE type IN('view','trigger')"
" OR(type='table'AND rootpage=0)",
zDbMain
);
if (rc) goto end_of_vacuum;
/* At this point, there is a write transaction open on both the
** vacuum database and the main database. Assuming no error occurs,
** both transactions are closed by this block - the main database
** transaction by sqlite3BtreeCopyFile() and the other by an explicit
** call to sqlite3BtreeCommit().
*/
{
u32 meta;
int i;
/* This array determines which meta meta values are preserved in the
** vacuum. Even entries are the meta value number and odd entries
** are an increment to apply to the meta value after the vacuum.
** The increment is used to increase the schema cookie so that other
** connections to the same database will know to reread the schema.
*/
static const unsigned char aCopy[] = {
BTREE_SCHEMA_VERSION, 1, /* Add one to the old schema cookie */
BTREE_DEFAULT_CACHE_SIZE, 0, /* Preserve the default page cache size */
BTREE_TEXT_ENCODING, 0, /* Preserve the text encoding */
BTREE_USER_VERSION, 0, /* Preserve the user version */
BTREE_APPLICATION_ID, 0, /* Preserve the application id */
};
assert(1 == sqlite3BtreeIsInTrans(pTemp));
assert(1 == sqlite3BtreeIsInTrans(pMain));
/* Copy Btree meta values */
for (i = 0; i<ArraySize(aCopy); i += 2) {
/* GetMeta() and UpdateMeta() cannot fail in this context because
** we already have page 1 loaded into cache and marked dirty. */
sqlite3BtreeGetMeta(pMain, aCopy[i], &meta);
rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta + aCopy[i + 1]);
if (NEVER(rc != SQLITE_OK)) goto end_of_vacuum;
}
rc = sqlite3BtreeCopyFile(pMain, pTemp);
if (rc != SQLITE_OK) goto end_of_vacuum;
rc = sqlite3BtreeCommit(pTemp);
if (rc != SQLITE_OK) goto end_of_vacuum;
#ifndef SQLITE_OMIT_AUTOVACUUM
sqlite3BtreeSetAutoVacuum(pMain, sqlite3BtreeGetAutoVacuum(pTemp));
#endif
}
assert(rc == SQLITE_OK);
rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes, 1);
end_of_vacuum:
/* Restore the original value of db->flags */
db->init.iDb = 0;
db->mDbFlags = saved_mDbFlags;
db->flags = saved_flags;
db->nChange = saved_nChange;
db->nTotalChange = saved_nTotalChange;
db->mTrace = saved_mTrace;
sqlite3BtreeSetPageSize(pMain, -1, -1, 1);
/* Currently there is an SQL level transaction open on the vacuum
** database. No locks are held on any other files (since the main file
** was committed at the btree level). So it safe to end the transaction
** by manually setting the autoCommit flag to true and detaching the
** vacuum database. The vacuum_db journal file is deleted when the pager
** is closed by the DETACH.
*/
db->autoCommit = 1;
if (pDb) {
sqlite3BtreeClose(pDb->pBt);
pDb->pBt = 0;
pDb->pSchema = 0;
}
/* This both clears the schemas and reduces the size of the db->aDb[]
** array. */
sqlite3ResetAllSchemasOfConnection(db);
return rc;
}
/*
** Parameter zSrcData points to a buffer containing the data for
** page iSrcPg from the source database. Copy this data into the
** destination database.
*/
static int backupOnePage(
sqlite3_backup *p, /* Backup handle */
Pgno iSrcPg, /* Source database page to backup */
const u8 *zSrcData, /* Source database page data */
int bUpdate /* True for an update, false otherwise */
){
Pager * const pDestPager = sqlite3BtreePager(p->pDest);
const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc);
int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest);
const int nCopy = MIN(nSrcPgsz, nDestPgsz);
const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz;
#ifdef SQLITE_HAS_CODEC
/* Use BtreeGetReserveNoMutex() for the source b-tree, as although it is
** guaranteed that the shared-mutex is held by this thread, handle
** p->pSrc may not actually be the owner. */
int nSrcReserve = sqlite3BtreeGetReserveNoMutex(p->pSrc);
int nDestReserve = sqlite3BtreeGetOptimalReserve(p->pDest);
#endif
int rc = SQLITE_OK;
i64 iOff;
assert( sqlite3BtreeGetReserveNoMutex(p->pSrc)>=0 );
assert( p->bDestLocked );
assert( !isFatalError(p->rc) );
assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) );
assert( zSrcData );
/* Catch the case where the destination is an in-memory database and the
** page sizes of the source and destination differ.
*/
if( nSrcPgsz!=nDestPgsz && sqlite3PagerIsMemdb(pDestPager) ){
rc = SQLITE_READONLY;
}
#ifdef SQLITE_HAS_CODEC
/* Backup is not possible if the page size of the destination is changing
** and a codec is in use.
*/
if( nSrcPgsz!=nDestPgsz && sqlite3PagerGetCodec(pDestPager)!=0 ){
rc = SQLITE_READONLY;
}
/* Backup is not possible if the number of bytes of reserve space differ
** between source and destination. If there is a difference, try to
** fix the destination to agree with the source. If that is not possible,
** then the backup cannot proceed.
*/
if( nSrcReserve!=nDestReserve ){
u32 newPgsz = nSrcPgsz;
rc = sqlite3PagerSetPagesize(pDestPager, &newPgsz, nSrcReserve);
if( rc==SQLITE_OK && newPgsz!=nSrcPgsz ) rc = SQLITE_READONLY;
}
#endif
/* This loop runs once for each destination page spanned by the source
** page. For each iteration, variable iOff is set to the byte offset
** of the destination page.
*/
for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){
DbPage *pDestPg = 0;
Pgno iDest = (Pgno)(iOff/nDestPgsz)+1;
if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue;
if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg, 0))
&& SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg))
){
const u8 *zIn = &zSrcData[iOff%nSrcPgsz];
u8 *zDestData = sqlite3PagerGetData(pDestPg);
u8 *zOut = &zDestData[iOff%nDestPgsz];
/* Copy the data from the source page into the destination page.
** Then clear the Btree layer MemPage.isInit flag. Both this module
** and the pager code use this trick (clearing the first byte
** of the page 'extra' space to invalidate the Btree layers
** cached parse of the page). MemPage.isInit is marked
** "MUST BE FIRST" for this purpose.
*/
memcpy(zOut, zIn, nCopy);
((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0;
if( iOff==0 && bUpdate==0 ){
sqlite3Put4byte(&zOut[28], sqlite3BtreeLastPage(p->pSrc));
}
}
sqlite3PagerUnref(pDestPg);
}
return rc;
}
