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Simplification of the OP_Column logic for the case of rows with overflow.

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FossilOrigin-Name: f73678038d8fc399c1ca55230ae45962007c909c
This commit is contained in:
drh
2014-09-16 18:22:44 +00:00
parent 897a2d50f2
commit 2a2a696cd7
4 changed files with 25 additions and 36 deletions
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38
src/vdbe.c
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@@ -2449,37 +2449,23 @@ case OP_Column: {
&& ((t>=12 && (t&1)==0) || (pOp->p5 & OPFLAG_TYPEOFARG)!=0))
|| (len = sqlite3VdbeSerialTypeLen(t))==0
){
/* Content is irrelevant for the typeof() function and for
** the length(X) function if X is a blob. So we might as well use
** bogus content rather than reading content from disk. NULL works
** for text and blob and whatever is in the payloadSize64 variable
** will work for everything else. Content is also irrelevant if
** the content length is 0. */
zData = t<=13 ? (u8*)&payloadSize64 : 0;
sMem.zMalloc = 0;
/* Content is irrelevant for
** 1. the typeof() function,
** 2. the length(X) function if X is a blob, and
** 3. if the content length is zero.
** So we might as well use bogus content rather than reading
** content from disk. NULL will work for the value for strings
** and blobs and whatever is in the payloadSize64 variable
** will work for everything else. */
sqlite3VdbeSerialGet(t<=13 ? (u8*)&payloadSize64 : 0, t, pDest);
}else{
memset(&sMem, 0, sizeof(sMem));
sqlite3VdbeMemMove(&sMem, pDest);
rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, !pC->isTable,
&sMem);
pDest);
if( rc!=SQLITE_OK ){
goto op_column_error;
}
zData = (u8*)sMem.z;
}
sqlite3VdbeSerialGet(zData, t, pDest);
/* If we dynamically allocated space to hold the data (in the
** sqlite3VdbeMemFromBtree() call above) then transfer control of that
** dynamically allocated space over to the pDest structure.
** This prevents a memory copy. */
if( sMem.zMalloc ){
assert( sMem.z==sMem.zMalloc );
assert( VdbeMemDynamic(pDest)==0 );
assert( (pDest->flags & (MEM_Blob|MEM_Str))==0 || pDest->z==sMem.z );
pDest->flags &= ~(MEM_Ephem|MEM_Static);
pDest->flags |= MEM_Term;
pDest->z = sMem.z;
pDest->zMalloc = sMem.zMalloc;
sqlite3VdbeSerialGet((const u8*)pDest->z, t, pDest);
pDest->flags &= ~MEM_Ephem;
}
}
pDest->enc = encoding;