diff -r 4a65cc85c4f3 -r fbd95db6a4e1 engine/sqlite/src/vacuum.cpp --- a/engine/sqlite/src/vacuum.cpp Wed Apr 28 13:20:05 2010 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,263 +0,0 @@ -/* -** 2003 April 6 -** -** The author disclaims copyright to this source code. In place of -** a legal notice, here is a blessing: -** -** May you do good and not evil. -** May you find forgiveness for yourself and forgive others. -** May you share freely, never taking more than you give. -** -************************************************************************* -** This file contains code used to implement the VACUUM command. -** -** Most of the code in this file may be omitted by defining the -** SQLITE_OMIT_VACUUM macro. -** -** $Id: vacuum.cpp 1282 2008-11-13 09:31:33Z LarsPson $ -*/ -#include "sqliteInt.h" -#include "vdbeInt.h" - -#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH) -/* -** Execute zSql on database db. Return an error code. -*/ -static int execSql(sqlite3 *db, const char *zSql){ - sqlite3_stmt *pStmt; - if( !zSql ){ - return SQLITE_NOMEM; - } - if( SQLITE_OK!=sqlite3_prepare(db, zSql, -1, &pStmt, 0) ){ - return sqlite3_errcode(db); - } - while( SQLITE_ROW==sqlite3_step(pStmt) ){} - return sqlite3_finalize(pStmt); -} - -/* -** Execute zSql on database db. The statement returns exactly -** one column. Execute this as SQL on the same database. -*/ -static int execExecSql(sqlite3 *db, const char *zSql){ - sqlite3_stmt *pStmt; - int rc; - - rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0); - if( rc!=SQLITE_OK ) return rc; - - while( SQLITE_ROW==sqlite3_step(pStmt) ){ - rc = execSql(db, (char*)sqlite3_column_text(pStmt, 0)); - if( rc!=SQLITE_OK ){ - sqlite3_finalize(pStmt); - return rc; - } - } - - return sqlite3_finalize(pStmt); -} - -/* -** The non-standard VACUUM command is used to clean up the database, -** collapse free space, etc. It is modelled after the VACUUM command -** in PostgreSQL. -** -** In version 1.0.x of SQLite, the VACUUM command would call -** gdbm_reorganize() on all the database tables. But beginning -** with 2.0.0, SQLite no longer uses GDBM so this command has -** become a no-op. -*/ -void sqlite3Vacuum(Parse *pParse){ - Vdbe *v = sqlite3GetVdbe(pParse); - if( v ){ - sqlite3VdbeAddOp(v, OP_Vacuum, 0, 0); - } - return; -} - -/* -** This routine implements the OP_Vacuum opcode of the VDBE. -*/ -int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){ - int rc = SQLITE_OK; /* Return code from service routines */ - Btree *pMain; /* The database being vacuumed */ - Btree *pTemp; /* The temporary database we vacuum into */ - char *zSql = 0; /* SQL statements */ - int saved_flags; /* Saved value of the db->flags */ - Db *pDb = 0; /* Database to detach at end of vacuum */ - - /* Save the current value of the write-schema flag before setting it. */ - saved_flags = db->flags; - db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks; - - if( !db->autoCommit ){ - sqlite3SetString(pzErrMsg, "cannot VACUUM from within a transaction", - (char*)0); - rc = SQLITE_ERROR; - goto end_of_vacuum; - } - pMain = db->aDb[0].pBt; - - /* 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. - */ - zSql = "ATTACH '' AS vacuum_db;"; - rc = execSql(db, zSql); - if( rc!=SQLITE_OK ) goto end_of_vacuum; - pDb = &db->aDb[db->nDb-1]; - assert( strcmp(db->aDb[db->nDb-1].zName,"vacuum_db")==0 ); - pTemp = db->aDb[db->nDb-1].pBt; - sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), - sqlite3BtreeGetReserve(pMain)); - if( db->mallocFailed ){ - rc = SQLITE_NOMEM; - goto end_of_vacuum; - } - assert( sqlite3BtreeGetPageSize(pTemp)==sqlite3BtreeGetPageSize(pMain) ); - rc = execSql(db, "PRAGMA vacuum_db.synchronous=OFF"); - if( rc!=SQLITE_OK ){ - goto end_of_vacuum; - } - -#ifndef SQLITE_OMIT_AUTOVACUUM - sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac>=0 ? db->nextAutovac : - sqlite3BtreeGetAutoVacuum(pMain)); -#endif - - /* Begin a transaction */ - rc = execSql(db, "BEGIN EXCLUSIVE;"); - if( rc!=SQLITE_OK ) goto end_of_vacuum; - - /* Query the schema of the main database. Create a mirror schema - ** in the temporary database. - */ - rc = execExecSql(db, - "SELECT 'CREATE TABLE vacuum_db.' || substr(sql,14) " - " FROM sqlite_master WHERE type='table' AND name!='sqlite_sequence'" - " AND rootpage>0" - ); - if( rc!=SQLITE_OK ) goto end_of_vacuum; - rc = execExecSql(db, - "SELECT 'CREATE INDEX vacuum_db.' || substr(sql,14)" - " FROM sqlite_master WHERE sql LIKE 'CREATE INDEX %' "); - if( rc!=SQLITE_OK ) goto end_of_vacuum; - rc = execExecSql(db, - "SELECT 'CREATE UNIQUE INDEX vacuum_db.' || substr(sql,21) " - " FROM sqlite_master WHERE sql LIKE 'CREATE UNIQUE INDEX %'"); - if( rc!=SQLITE_OK ) goto end_of_vacuum; - - /* Loop through the tables in the main database. For each, do - ** an "INSERT INTO vacuum_db.xxx SELECT * FROM xxx;" to copy - ** the contents to the temporary database. - */ - rc = execExecSql(db, - "SELECT 'INSERT INTO vacuum_db.' || quote(name) " - "|| ' SELECT * FROM ' || quote(name) || ';'" - "FROM sqlite_master " - "WHERE type = 'table' AND name!='sqlite_sequence' " - " AND rootpage>0" - - ); - if( rc!=SQLITE_OK ) goto end_of_vacuum; - - /* Copy over the sequence table - */ - rc = execExecSql(db, - "SELECT 'DELETE FROM vacuum_db.' || quote(name) || ';' " - "FROM vacuum_db.sqlite_master WHERE name='sqlite_sequence' " - ); - if( rc!=SQLITE_OK ) goto end_of_vacuum; - rc = execExecSql(db, - "SELECT 'INSERT INTO vacuum_db.' || quote(name) " - "|| ' SELECT * FROM ' || quote(name) || ';' " - "FROM vacuum_db.sqlite_master WHERE name=='sqlite_sequence';" - ); - 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 = execSql(db, - "INSERT INTO vacuum_db.sqlite_master " - " SELECT type, name, tbl_name, rootpage, sql" - " FROM sqlite_master" - " WHERE type='view' OR type='trigger'" - " OR (type='table' AND rootpage=0)" - ); - if( rc ) goto end_of_vacuum; - - /* At this point, unless the main db was completely empty, there is now a - ** transaction open on the vacuum database, but not on the main database. - ** Open a btree level transaction on the main database. This allows a - ** call to sqlite3BtreeCopyFile(). The main database btree level - ** transaction is then committed, so the SQL level never knows it was - ** opened for writing. This way, the SQL transaction used to create the - ** temporary database never needs to be committed. - */ - if( rc==SQLITE_OK ){ - 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[] = { - 1, 1, /* Add one to the old schema cookie */ - 3, 0, /* Preserve the default page cache size */ - 5, 0, /* Preserve the default text encoding */ - 6, 0, /* Preserve the user version */ - }; - - assert( 1==sqlite3BtreeIsInTrans(pTemp) ); - assert( 1==sqlite3BtreeIsInTrans(pMain) ); - - /* Copy Btree meta values */ - for(i=0; iflags */ - db->flags = saved_flags; - - /* 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; - } - - sqlite3ResetInternalSchema(db, 0); - - return rc; -} -#endif /* SQLITE_OMIT_VACUUM && SQLITE_OMIT_ATTACH */