1.1 --- a/extensions/sqlite/sqlite-source/vacuum.c Fri Mar 28 06:21:34 2008 +0000
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,262 +0,0 @@
1.4 -/*
1.5 -** 2003 April 6
1.6 -**
1.7 -** The author disclaims copyright to this source code. In place of
1.8 -** a legal notice, here is a blessing:
1.9 -**
1.10 -** May you do good and not evil.
1.11 -** May you find forgiveness for yourself and forgive others.
1.12 -** May you share freely, never taking more than you give.
1.13 -**
1.14 -*************************************************************************
1.15 -** This file contains code used to implement the VACUUM command.
1.16 -**
1.17 -** Most of the code in this file may be omitted by defining the
1.18 -** SQLITE_OMIT_VACUUM macro.
1.19 -**
1.20 -** $Id$
1.21 -*/
1.22 -#include "sqliteInt.h"
1.23 -#include "vdbeInt.h"
1.24 -
1.25 -#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
1.26 -/*
1.27 -** Execute zSql on database db. Return an error code.
1.28 -*/
1.29 -static int execSql(sqlite3 *db, const char *zSql){
1.30 - sqlite3_stmt *pStmt;
1.31 - if( !zSql ){
1.32 - return SQLITE_NOMEM;
1.33 - }
1.34 - if( SQLITE_OK!=sqlite3_prepare(db, zSql, -1, &pStmt, 0) ){
1.35 - return sqlite3_errcode(db);
1.36 - }
1.37 - while( SQLITE_ROW==sqlite3_step(pStmt) ){}
1.38 - return sqlite3_finalize(pStmt);
1.39 -}
1.40 -
1.41 -/*
1.42 -** Execute zSql on database db. The statement returns exactly
1.43 -** one column. Execute this as SQL on the same database.
1.44 -*/
1.45 -static int execExecSql(sqlite3 *db, const char *zSql){
1.46 - sqlite3_stmt *pStmt;
1.47 - int rc;
1.48 -
1.49 - rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
1.50 - if( rc!=SQLITE_OK ) return rc;
1.51 -
1.52 - while( SQLITE_ROW==sqlite3_step(pStmt) ){
1.53 - rc = execSql(db, (char*)sqlite3_column_text(pStmt, 0));
1.54 - if( rc!=SQLITE_OK ){
1.55 - sqlite3_finalize(pStmt);
1.56 - return rc;
1.57 - }
1.58 - }
1.59 -
1.60 - return sqlite3_finalize(pStmt);
1.61 -}
1.62 -
1.63 -/*
1.64 -** The non-standard VACUUM command is used to clean up the database,
1.65 -** collapse free space, etc. It is modelled after the VACUUM command
1.66 -** in PostgreSQL.
1.67 -**
1.68 -** In version 1.0.x of SQLite, the VACUUM command would call
1.69 -** gdbm_reorganize() on all the database tables. But beginning
1.70 -** with 2.0.0, SQLite no longer uses GDBM so this command has
1.71 -** become a no-op.
1.72 -*/
1.73 -void sqlite3Vacuum(Parse *pParse){
1.74 - Vdbe *v = sqlite3GetVdbe(pParse);
1.75 - if( v ){
1.76 - sqlite3VdbeAddOp(v, OP_Vacuum, 0, 0);
1.77 - }
1.78 - return;
1.79 -}
1.80 -
1.81 -/*
1.82 -** This routine implements the OP_Vacuum opcode of the VDBE.
1.83 -*/
1.84 -int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
1.85 - int rc = SQLITE_OK; /* Return code from service routines */
1.86 - Btree *pMain; /* The database being vacuumed */
1.87 - Btree *pTemp; /* The temporary database we vacuum into */
1.88 - char *zSql = 0; /* SQL statements */
1.89 - int saved_flags; /* Saved value of the db->flags */
1.90 - Db *pDb = 0; /* Database to detach at end of vacuum */
1.91 -
1.92 - /* Save the current value of the write-schema flag before setting it. */
1.93 - saved_flags = db->flags;
1.94 - db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;
1.95 -
1.96 - if( !db->autoCommit ){
1.97 - sqlite3SetString(pzErrMsg, "cannot VACUUM from within a transaction",
1.98 - (char*)0);
1.99 - rc = SQLITE_ERROR;
1.100 - goto end_of_vacuum;
1.101 - }
1.102 - pMain = db->aDb[0].pBt;
1.103 -
1.104 - /* Attach the temporary database as 'vacuum_db'. The synchronous pragma
1.105 - ** can be set to 'off' for this file, as it is not recovered if a crash
1.106 - ** occurs anyway. The integrity of the database is maintained by a
1.107 - ** (possibly synchronous) transaction opened on the main database before
1.108 - ** sqlite3BtreeCopyFile() is called.
1.109 - **
1.110 - ** An optimisation would be to use a non-journaled pager.
1.111 - */
1.112 - zSql = "ATTACH '' AS vacuum_db;";
1.113 - rc = execSql(db, zSql);
1.114 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.115 - pDb = &db->aDb[db->nDb-1];
1.116 - assert( strcmp(db->aDb[db->nDb-1].zName,"vacuum_db")==0 );
1.117 - pTemp = db->aDb[db->nDb-1].pBt;
1.118 - sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain),
1.119 - sqlite3BtreeGetReserve(pMain));
1.120 - if( db->mallocFailed ){
1.121 - rc = SQLITE_NOMEM;
1.122 - goto end_of_vacuum;
1.123 - }
1.124 - assert( sqlite3BtreeGetPageSize(pTemp)==sqlite3BtreeGetPageSize(pMain) );
1.125 - rc = execSql(db, "PRAGMA vacuum_db.synchronous=OFF");
1.126 - if( rc!=SQLITE_OK ){
1.127 - goto end_of_vacuum;
1.128 - }
1.129 -
1.130 -#ifndef SQLITE_OMIT_AUTOVACUUM
1.131 - sqlite3BtreeSetAutoVacuum(pTemp, sqlite3BtreeGetAutoVacuum(pMain));
1.132 -#endif
1.133 -
1.134 - /* Begin a transaction */
1.135 - rc = execSql(db, "BEGIN EXCLUSIVE;");
1.136 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.137 -
1.138 - /* Query the schema of the main database. Create a mirror schema
1.139 - ** in the temporary database.
1.140 - */
1.141 - rc = execExecSql(db,
1.142 - "SELECT 'CREATE TABLE vacuum_db.' || substr(sql,14,100000000) "
1.143 - " FROM sqlite_master WHERE type='table' AND name!='sqlite_sequence'"
1.144 - " AND rootpage>0"
1.145 - );
1.146 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.147 - rc = execExecSql(db,
1.148 - "SELECT 'CREATE INDEX vacuum_db.' || substr(sql,14,100000000)"
1.149 - " FROM sqlite_master WHERE sql LIKE 'CREATE INDEX %' ");
1.150 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.151 - rc = execExecSql(db,
1.152 - "SELECT 'CREATE UNIQUE INDEX vacuum_db.' || substr(sql,21,100000000) "
1.153 - " FROM sqlite_master WHERE sql LIKE 'CREATE UNIQUE INDEX %'");
1.154 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.155 -
1.156 - /* Loop through the tables in the main database. For each, do
1.157 - ** an "INSERT INTO vacuum_db.xxx SELECT * FROM xxx;" to copy
1.158 - ** the contents to the temporary database.
1.159 - */
1.160 - rc = execExecSql(db,
1.161 - "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
1.162 - "|| ' SELECT * FROM ' || quote(name) || ';'"
1.163 - "FROM sqlite_master "
1.164 - "WHERE type = 'table' AND name!='sqlite_sequence' "
1.165 - " AND rootpage>0"
1.166 -
1.167 - );
1.168 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.169 -
1.170 - /* Copy over the sequence table
1.171 - */
1.172 - rc = execExecSql(db,
1.173 - "SELECT 'DELETE FROM vacuum_db.' || quote(name) || ';' "
1.174 - "FROM vacuum_db.sqlite_master WHERE name='sqlite_sequence' "
1.175 - );
1.176 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.177 - rc = execExecSql(db,
1.178 - "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
1.179 - "|| ' SELECT * FROM ' || quote(name) || ';' "
1.180 - "FROM vacuum_db.sqlite_master WHERE name=='sqlite_sequence';"
1.181 - );
1.182 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.183 -
1.184 -
1.185 - /* Copy the triggers, views, and virtual tables from the main database
1.186 - ** over to the temporary database. None of these objects has any
1.187 - ** associated storage, so all we have to do is copy their entries
1.188 - ** from the SQLITE_MASTER table.
1.189 - */
1.190 - rc = execSql(db,
1.191 - "INSERT INTO vacuum_db.sqlite_master "
1.192 - " SELECT type, name, tbl_name, rootpage, sql"
1.193 - " FROM sqlite_master"
1.194 - " WHERE type='view' OR type='trigger'"
1.195 - " OR (type='table' AND rootpage=0)"
1.196 - );
1.197 - if( rc ) goto end_of_vacuum;
1.198 -
1.199 - /* At this point, unless the main db was completely empty, there is now a
1.200 - ** transaction open on the vacuum database, but not on the main database.
1.201 - ** Open a btree level transaction on the main database. This allows a
1.202 - ** call to sqlite3BtreeCopyFile(). The main database btree level
1.203 - ** transaction is then committed, so the SQL level never knows it was
1.204 - ** opened for writing. This way, the SQL transaction used to create the
1.205 - ** temporary database never needs to be committed.
1.206 - */
1.207 - if( rc==SQLITE_OK ){
1.208 - u32 meta;
1.209 - int i;
1.210 -
1.211 - /* This array determines which meta meta values are preserved in the
1.212 - ** vacuum. Even entries are the meta value number and odd entries
1.213 - ** are an increment to apply to the meta value after the vacuum.
1.214 - ** The increment is used to increase the schema cookie so that other
1.215 - ** connections to the same database will know to reread the schema.
1.216 - */
1.217 - static const unsigned char aCopy[] = {
1.218 - 1, 1, /* Add one to the old schema cookie */
1.219 - 3, 0, /* Preserve the default page cache size */
1.220 - 5, 0, /* Preserve the default text encoding */
1.221 - 6, 0, /* Preserve the user version */
1.222 - };
1.223 -
1.224 - assert( 1==sqlite3BtreeIsInTrans(pTemp) );
1.225 - assert( 1==sqlite3BtreeIsInTrans(pMain) );
1.226 -
1.227 - /* Copy Btree meta values */
1.228 - for(i=0; i<sizeof(aCopy)/sizeof(aCopy[0]); i+=2){
1.229 - rc = sqlite3BtreeGetMeta(pMain, aCopy[i], &meta);
1.230 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.231 - rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta+aCopy[i+1]);
1.232 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.233 - }
1.234 -
1.235 - rc = sqlite3BtreeCopyFile(pMain, pTemp);
1.236 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.237 - rc = sqlite3BtreeCommit(pTemp);
1.238 - if( rc!=SQLITE_OK ) goto end_of_vacuum;
1.239 - rc = sqlite3BtreeCommit(pMain);
1.240 - }
1.241 -
1.242 -end_of_vacuum:
1.243 - /* Restore the original value of db->flags */
1.244 - db->flags = saved_flags;
1.245 -
1.246 - /* Currently there is an SQL level transaction open on the vacuum
1.247 - ** database. No locks are held on any other files (since the main file
1.248 - ** was committed at the btree level). So it safe to end the transaction
1.249 - ** by manually setting the autoCommit flag to true and detaching the
1.250 - ** vacuum database. The vacuum_db journal file is deleted when the pager
1.251 - ** is closed by the DETACH.
1.252 - */
1.253 - db->autoCommit = 1;
1.254 -
1.255 - if( pDb ){
1.256 - sqlite3BtreeClose(pDb->pBt);
1.257 - pDb->pBt = 0;
1.258 - pDb->pSchema = 0;
1.259 - }
1.260 -
1.261 - sqlite3ResetInternalSchema(db, 0);
1.262 -
1.263 - return rc;
1.264 -}
1.265 -#endif /* SQLITE_OMIT_VACUUM && SQLITE_OMIT_ATTACH */
