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Minor change to wal.c on this branch to make it more similar to trunk.

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FossilOrigin-Name: 6a7af3ead5949c461430c1fa92798dc2bbbc58c8cd504005c5afa38993f0be82
This commit is contained in:
dan
2018-12-03 20:38:15 +00:00
parent 51883dfc8b
commit 834c48c279
3 changed files with 35 additions and 56 deletions
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73
src/wal.c
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@@ -2854,19 +2854,37 @@ void sqlite3WalEndReadTransaction(Wal *pWal){
}
/*
** Search the hash tables for an entry matching page number pgno. Ignore
** any entries that lie after frame iLast within the wal file.
** Search the wal file for page pgno. If found, set *piRead to the frame that
** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
** to zero.
**
** Return SQLITE_OK if successful, or an error code if an error occurs. If an
** error does occur, the final value of *piRead is undefined.
*/
static int walFindFrame(
Wal *pWal,
Pgno pgno,
u32 iLast,
u32 *piRead
int sqlite3WalFindFrame(
Wal *pWal, /* WAL handle */
Pgno pgno, /* Database page number to read data for */
u32 *piRead /* OUT: Frame number (or zero) */
){
u32 iRead = 0; /* If !=0, WAL frame to return data from */
u32 iLast = pWal->hdr.mxFrame; /* Last page in WAL for this reader */
int iHash; /* Used to loop through N hash tables */
u32 iRead = 0;
int iMinHash;
/* This routine is only be called from within a read transaction. */
assert( pWal->readLock>=0 || pWal->lockError );
/* If the "last page" field of the wal-index header snapshot is 0, then
** no data will be read from the wal under any circumstances. Return early
** in this case as an optimization. Likewise, if pWal->readLock==0,
** then the WAL is ignored by the reader so return early, as if the
** WAL were empty.
*/
if( iLast==0 || (pWal->readLock==0 && pWal->bShmUnreliable==0) ){
*piRead = 0;
return SQLITE_OK;
}
/* Each iteration of the following for() loop searches one
** hash table (each hash table indexes up to HASHTABLE_NPAGE frames).
**
@@ -2917,43 +2935,6 @@ static int walFindFrame(
if( iRead ) break;
}
*piRead = iRead;
return SQLITE_OK;
}
/*
** Search the wal file for page pgno. If found, set *piRead to the frame that
** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
** to zero.
**
** Return SQLITE_OK if successful, or an error code if an error occurs. If an
** error does occur, the final value of *piRead is undefined.
*/
int sqlite3WalFindFrame(
Wal *pWal, /* WAL handle */
Pgno pgno, /* Database page number to read data for */
u32 *piRead /* OUT: Frame number (or zero) */
){
u32 iRead = 0; /* If !=0, WAL frame to return data from */
u32 iLast = pWal->hdr.mxFrame; /* Last page in WAL for this reader */
int rc;
/* This routine is only be called from within a read transaction. */
assert( pWal->readLock>=0 || pWal->lockError );
/* If the "last page" field of the wal-index header snapshot is 0, then
** no data will be read from the wal under any circumstances. Return early
** in this case as an optimization. Likewise, if pWal->readLock==0,
** then the WAL is ignored by the reader so return early, as if the
** WAL were empty.
*/
if( iLast==0 || (pWal->readLock==0 && pWal->bShmUnreliable==0) ){
*piRead = 0;
return SQLITE_OK;
}
rc = walFindFrame(pWal, pgno, iLast, &iRead);
#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
/* If expensive assert() statements are available, do a linear search
** of the wal-index file content. Make sure the results agree with the
@@ -2973,7 +2954,7 @@ int sqlite3WalFindFrame(
#endif
*piRead = iRead;
return rc;
return SQLITE_OK;
}
/*