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Overview
| Comment: | Ensure that write-locks on pages are dropped at the end of each write transaction, even if there is still a read transaction open. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | server-process-edition |
| Files: | files | file ages | folders |
| SHA3-256: |
2dd36ade9ea948de27b217b83cbf704e |
| User & Date: | dan 2017-08-19 15:50:45 |
Context
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2017-08-29
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| 17:52 | Add a Tcl script to run the performance tests described in README-server-edition.html. (check-in: 1b3df8ff user: dan tags: server-process-edition) | |
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2017-08-19
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| 15:50 | Ensure that write-locks on pages are dropped at the end of each write transaction, even if there is still a read transaction open. (check-in: 2dd36ade user: dan tags: server-process-edition) | |
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2017-08-18
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| 18:55 | Add tests to this branch. (check-in: abb6e076 user: dan tags: server-process-edition) | |
Changes
Changes to src/pager.c.
2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 |
if( rc==SQLITE_OK && bCommit && isOpen(pPager->fd) ){
rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_COMMIT_PHASETWO, 0);
if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
}
#ifdef SQLITE_SERVER_EDITION
if( pagerIsServer(pPager) ){
rc2 = sqlite3ServerReleaseWriteLocks(pPager->pServer);
}else
#endif
if( !pPager->exclusiveMode
&& (!pagerUseWal(pPager) || sqlite3WalExclusiveMode(pPager->pWal, 0))
){
rc2 = pagerUnlockDb(pPager, SHARED_LOCK);
pPager->changeCountDone = 0;
|
| |
2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 |
if( rc==SQLITE_OK && bCommit && isOpen(pPager->fd) ){
rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_COMMIT_PHASETWO, 0);
if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
}
#ifdef SQLITE_SERVER_EDITION
if( pagerIsServer(pPager) ){
rc2 = sqlite3ServerEndWrite(pPager->pServer);
}else
#endif
if( !pPager->exclusiveMode
&& (!pagerUseWal(pPager) || sqlite3WalExclusiveMode(pPager->pWal, 0))
){
rc2 = pagerUnlockDb(pPager, SHARED_LOCK);
pPager->changeCountDone = 0;
|
Changes to src/server.c.
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if( serverCompareAndSwap(pSlot, o, n) ) break;
}
}
p->nLock = 0;
}
/*
** End a transaction (and release all locks). This version runs in
** single process mode only.
*/
static void serverEndSingle(Server *p){
Server **pp;
ServerDb *pDb = p->pDb;
ServerPage *pPg = 0;
assert( p->eTrans!=SERVER_TRANS_NONE );
assert( pDb->pServerShm==0 );
sqlite3_mutex_enter(pDb->mutex);
if( p->eTrans==SERVER_TRANS_READONLY ){
/* Remove the connection from the readers list */
for(pp=&pDb->pReader; *pp!=p; pp = &((*pp)->pNext));
*pp = p->pNext;
}else{
serverReleaseLocks(p);
/* Clear the bit in the transaction mask. */
pDb->transmask &= ~((u32)1 << p->iTransId);
/* If this connection is in the committers list, remove it. */
for(pp=&pDb->pCommit; *pp; pp = &((*pp)->pNext)){
if( *pp==p ){
*pp = p->pNext;
break;
}
}
}
/* See if it is possible to free any ServerPage records. If so, remove
** them from the linked list and hash table, but do not call sqlite3_free()
** on them until the mutex has been released. */
if( pDb->pPgFirst ){
ServerPage *pLast = 0;
Server *pIter;
int iOldest = 0x7FFFFFFF;
for(pIter=pDb->pReader; pIter; pIter=pIter->pNext){
iOldest = MIN(iOldest, pIter->iCommitId);
}
for(pIter=pDb->pCommit; pIter; pIter=pIter->pNext){
iOldest = MIN(iOldest, pIter->iCommitId);
}
................................................................................
if( pPg==0 ){
pDb->pPgFirst = pDb->pPgLast = 0;
}else{
pDb->pPgFirst = pPg;
}
}
sqlite3_mutex_leave(pDb->mutex);
p->pNext = 0;
p->iTransId = -1;
p->iCommitId = 0;
}
/*
** End a transaction (and release all locks).
*/
int sqlite3ServerEnd(Server *p){
if( p->eTrans!=SERVER_TRANS_NONE ){
................................................................................
sqlite3_mutex_leave(pDb->mutex);
return rc;
}
/*
** Release all write-locks.
*/
int sqlite3ServerReleaseWriteLocks(Server *p){
int rc = SQLITE_OK;
return rc;
}
static int serverCheckClient(Server *p, int iClient){
ServerDb *pDb = p->pDb;
int rc = SQLITE_BUSY_DEADLOCK;
if( pDb->pServerShm && 0==(pDb->transmask & (1 << iClient)) ){
................................................................................
p->aLock[p->nLock++] = pgno;
}
}
return rc;
}
int sqlite3ServerHasLock(Server *p, Pgno pgno, int bWrite){
assert( 0 );
return 0;
}
static void serverIncrSlowReader(u32 *pSlot, int n){
assert( n==1 || n==-1 );
*pSlot += (n * (1 << HMA_SLOT_RLWL_BITS));
}
void sqlite3ServerReadPage(Server *p, Pgno pgno, u8 **ppData){
if( p->eTrans==SERVER_TRANS_READONLY ){
|
< < < < | < < < < < < | < < < < < < < < < < < < < < < < < < < | < > | > | > > > > > > > > > > > > > > > > > > > > > > > > > > < | | > > > > > > > > > > > > > > > > > > > > > > > > > > > > | < < < < < |
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if( serverCompareAndSwap(pSlot, o, n) ) break;
}
}
p->nLock = 0;
}
static void serverRecycleBuffers(ServerDb *pDb){
assert( pDb->pServerShm==0 );
assert( sqlite3_mutex_held(pDb->mutex) );
/* See if it is possible to free any ServerPage records. If so, remove
** them from the linked list and hash table, and add them to the pFree
** list. */
if( pDb->pPgFirst ){
ServerPage *pPg;
Server *pIter;
ServerPage *pLast = 0;
int iOldest = 0x7FFFFFFF;
for(pIter=pDb->pReader; pIter; pIter=pIter->pNext){
iOldest = MIN(iOldest, pIter->iCommitId);
}
for(pIter=pDb->pCommit; pIter; pIter=pIter->pNext){
iOldest = MIN(iOldest, pIter->iCommitId);
}
................................................................................
if( pPg==0 ){
pDb->pPgFirst = pDb->pPgLast = 0;
}else{
pDb->pPgFirst = pPg;
}
}
}
/*
** End a transaction (and release all locks). This version runs in
** single process mode only.
*/
static void serverEndSingle(Server *p){
Server **pp;
ServerDb *pDb = p->pDb;
assert( p->eTrans!=SERVER_TRANS_NONE );
assert( pDb->pServerShm==0 );
sqlite3_mutex_enter(pDb->mutex);
if( p->eTrans==SERVER_TRANS_READONLY ){
/* Remove the connection from the readers list */
for(pp=&pDb->pReader; *pp!=p; pp = &((*pp)->pNext));
*pp = p->pNext;
}else{
serverReleaseLocks(p);
/* Clear the bit in the transaction mask. */
pDb->transmask &= ~((u32)1 << p->iTransId);
}
serverRecycleBuffers(pDb);
sqlite3_mutex_leave(pDb->mutex);
p->pNext = 0;
p->iTransId = -1;
}
/*
** End a transaction (and release all locks).
*/
int sqlite3ServerEnd(Server *p){
if( p->eTrans!=SERVER_TRANS_NONE ){
................................................................................
sqlite3_mutex_leave(pDb->mutex);
return rc;
}
/*
** Release all write-locks.
*/
int sqlite3ServerEndWrite(Server *p){
ServerDb *pDb = p->pDb;
int i;
if( pDb->pServerShm==0 ) sqlite3_mutex_enter(pDb->mutex);
for(i=0; i<p->nLock; i++){
while( 1 ){
u32 *pSlot = serverLockingSlot(pDb, p->aLock[i]);
u32 o = *pSlot;
u32 n = o & ~((u32)1 << p->iTransId);
if( slotGetWriter(n)==p->iTransId ){
n -= ((p->iTransId + 1) << HMA_MAX_TRANSACTIONID);
n |= ((u32)1 << p->iTransId);
}
if( o==n || serverCompareAndSwap(pSlot, o, n) ) break;
}
}
if( pDb->pServerShm==0 ){
ServerDb **pp;
/* If this connection is in the committers list, remove it. */
for(pp=&pDb->pCommit; *pp; pp = &((*pp)->pNext)){
if( *pp==p ){
*pp = p->pNext;
break;
}
}
p->iCommitId = 0;
sqlite3_mutex_leave(pDb->mutex);
}
return SQLITE_OK;
}
static int serverCheckClient(Server *p, int iClient){
ServerDb *pDb = p->pDb;
int rc = SQLITE_BUSY_DEADLOCK;
if( pDb->pServerShm && 0==(pDb->transmask & (1 << iClient)) ){
................................................................................
p->aLock[p->nLock++] = pgno;
}
}
return rc;
}
static void serverIncrSlowReader(u32 *pSlot, int n){
assert( n==1 || n==-1 );
*pSlot += (n * (1 << HMA_SLOT_RLWL_BITS));
}
void sqlite3ServerReadPage(Server *p, Pgno pgno, u8 **ppData){
if( p->eTrans==SERVER_TRANS_READONLY ){
|
Changes to src/server.h.
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 |
int sqlite3ServerConnect(Pager *pPager, int eServer, Server **ppOut); void sqlite3ServerDisconnect(Server *p, sqlite3_file *dbfd); int sqlite3ServerBegin(Server *p, int bReadonly); int sqlite3ServerPreCommit(Server*, ServerPage*); int sqlite3ServerEnd(Server *p); int sqlite3ServerReleaseWriteLocks(Server *p); int sqlite3ServerLock(Server *p, Pgno pgno, int bWrite, int bBlock); int sqlite3ServerHasLock(Server *p, Pgno pgno, int bWrite); ServerPage *sqlite3ServerBuffer(Server*); int sqlite3ServerIsSingleProcess(Server*); /* For "BEGIN READONLY" clients. */ int sqlite3ServerIsReadonly(Server*); void sqlite3ServerReadPage(Server*, Pgno, u8**); void sqlite3ServerEndReadPage(Server*, Pgno); #endif /* SQLITE_SERVER_H */ #endif /* SQLITE_SERVER_EDITION */ |
| < < |
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 |
int sqlite3ServerConnect(Pager *pPager, int eServer, Server **ppOut);
void sqlite3ServerDisconnect(Server *p, sqlite3_file *dbfd);
int sqlite3ServerBegin(Server *p, int bReadonly);
int sqlite3ServerPreCommit(Server*, ServerPage*);
int sqlite3ServerEnd(Server *p);
int sqlite3ServerEndWrite(Server *p);
int sqlite3ServerLock(Server *p, Pgno pgno, int bWrite, int bBlock);
ServerPage *sqlite3ServerBuffer(Server*);
int sqlite3ServerIsSingleProcess(Server*);
/* For "BEGIN READONLY" clients. */
int sqlite3ServerIsReadonly(Server*);
void sqlite3ServerReadPage(Server*, Pgno, u8**);
void sqlite3ServerEndReadPage(Server*, Pgno);
#endif /* SQLITE_SERVER_H */
#endif /* SQLITE_SERVER_EDITION */
|
Changes to test/server2.test.
138 139 140 141 142 143 144 145 146 147 148 |
lsort [glob -nocomplain test.db-journal/*-journal]
} {test.db-journal/0-journal}
do_test $tn.3.2 {
db close
lsort [glob -nocomplain test.db-journal/*-journal]
} {}
}
finish_test
|
> > > > > > > > > > > > > > > > > > > > > > > > > > > |
138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 |
lsort [glob -nocomplain test.db-journal/*-journal]
} {test.db-journal/0-journal}
do_test $tn.3.2 {
db close
lsort [glob -nocomplain test.db-journal/*-journal]
} {}
#-----------------------------------------------------------------------
# Test that write-locks are downgraded when a transaction is ended,
# even if the connection holds an open read statement.
#
do_test $tn.4.1 {
server_sqlite3 db test.db
server_sqlite3 db2 test.db
db eval {
CREATE TABLE t2(a);
INSERT INTO t2 VALUES('one');
INSERT INTO t2 VALUES('two');
INSERT INTO t2 VALUES('three');
CREATE TABLE t3(k INTEGER PRIMARY KEY, val);
}
set res [list]
db eval { SELECT a FROM t2 ORDER BY rowid } {
db eval { REPLACE INTO t3 VALUES(1, $a) }
lappend res [db2 one { SELECT val FROM t3 }]
}
set res
} {one two three}
catch { db close }
catch { db2 close }
}
finish_test
|