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Get the ABORT conflict resolution algorithm working. (CVS 362)

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FossilOrigin-Name: 9be4d4c6f12056782966396dca0b8e2d384d0cf2
This commit is contained in:
drh
2002-02-02 18:49:19 +00:00
parent fa86c4127d
commit 663fc63a77
12 changed files with 508 additions and 234 deletions
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64
src/btree.c
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@@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.46 2002/01/04 03:09:29 drh Exp $
** $Id: btree.c,v 1.47 2002/02/02 18:49:20 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
@@ -302,7 +302,8 @@ struct Btree {
Pager *pPager; /* The page cache */
BtCursor *pCursor; /* A list of all open cursors */
PageOne *page1; /* First page of the database */
int inTrans; /* True if a transaction is in progress */
u8 inTrans; /* True if a transaction is in progress */
u8 inCkpt; /* True if there is a checkpoint on the transaction */
Hash locks; /* Key: root page number. Data: lock count */
};
typedef Btree Bt;
@@ -691,6 +692,7 @@ static void unlockBtreeIfUnused(Btree *pBt){
sqlitepager_unref(pBt->page1);
pBt->page1 = 0;
pBt->inTrans = 0;
pBt->inCkpt = 0;
}
}
@@ -753,6 +755,7 @@ int sqliteBtreeBeginTrans(Btree *pBt){
}
if( rc==SQLITE_OK ){
pBt->inTrans = 1;
pBt->inCkpt = 0;
}else{
unlockBtreeIfUnused(pBt);
}
@@ -770,6 +773,7 @@ int sqliteBtreeCommit(Btree *pBt){
if( pBt->inTrans==0 ) return SQLITE_ERROR;
rc = sqlitepager_commit(pBt->pPager);
pBt->inTrans = 0;
pBt->inCkpt = 0;
unlockBtreeIfUnused(pBt);
return rc;
}
@@ -788,6 +792,7 @@ int sqliteBtreeRollback(Btree *pBt){
BtCursor *pCur;
if( pBt->inTrans==0 ) return SQLITE_OK;
pBt->inTrans = 0;
pBt->inCkpt = 0;
for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
if( pCur->pPage ){
sqlitepager_unref(pCur->pPage);
@@ -799,6 +804,61 @@ int sqliteBtreeRollback(Btree *pBt){
return rc;
}
/*
** Set the checkpoint for the current transaction. The checkpoint serves
** as a sub-transaction that can be rolled back independently of the
** main transaction. You must start a transaction before starting a
** checkpoint. The checkpoint is ended automatically if the transaction
** commits or rolls back.
**
** Only one checkpoint may be active at a time. It is an error to try
** to start a new checkpoint if another checkpoint is already active.
*/
int sqliteBtreeBeginCkpt(Btree *pBt){
int rc;
if( !pBt->inTrans || pBt->inCkpt ) return SQLITE_ERROR;
rc = sqlitepager_ckpt_begin(pBt->pPager);
pBt->inCkpt = 1;
return rc;
}
/*
** Commit a checkpoint to transaction currently in progress. If no
** checkpoint is active, this is a no-op.
*/
int sqliteBtreeCommitCkpt(Btree *pBt){
int rc;
if( pBt->inCkpt ){
rc = sqlitepager_ckpt_commit(pBt->pPager);
}else{
rc = SQLITE_OK;
}
return rc;
}
/*
** Rollback the checkpoint to the current transaction. If there
** is no active checkpoint or transaction, this routine is a no-op.
**
** All cursors will be invalided by this operation. Any attempt
** to use a cursor that was open at the beginning of this operation
** will result in an error.
*/
int sqliteBtreeRollbackCkpt(Btree *pBt){
int rc;
BtCursor *pCur;
if( pBt->inCkpt==0 ) return SQLITE_OK;
for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
if( pCur->pPage ){
sqlitepager_unref(pCur->pPage);
pCur->pPage = 0;
}
}
rc = sqlitepager_ckpt_rollback(pBt->pPager);
return rc;
}
/*
** Create a new cursor for the BTree whose root is on the page
** iTable. The act of acquiring a cursor gets a read lock on