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When vacuuming an index that uses no collations other than BINARY, assume that the order of index entries will not be changed by the VACUUM.

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FossilOrigin-Name: e403460b96814ac8cb976d58b27939b3bd3c61f9
This commit is contained in:
dan
2015-04-01 18:20:25 +00:00
parent b18e60b3e4
commit e34162b14f
5 changed files with 54 additions and 17 deletions
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48
src/insert.c
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@@ -1765,6 +1765,7 @@ static int xferOptimization(
int onError, /* How to handle constraint errors */
int iDbDest /* The database of pDest */
){
sqlite3 *db = pParse->db;
ExprList *pEList; /* The result set of the SELECT */
Table *pSrc; /* The table in the FROM clause of SELECT */
Index *pSrcIdx, *pDestIdx; /* Source and destination indices */
@@ -1912,11 +1913,11 @@ static int xferOptimization(
** the extra complication to make this rule less restrictive is probably
** not worth the effort. Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
*/
if( (pParse->db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
if( (db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
return 0;
}
#endif
if( (pParse->db->flags & SQLITE_CountRows)!=0 ){
if( (db->flags & SQLITE_CountRows)!=0 ){
return 0; /* xfer opt does not play well with PRAGMA count_changes */
}
@@ -1927,7 +1928,7 @@ static int xferOptimization(
#ifdef SQLITE_TEST
sqlite3_xferopt_count++;
#endif
iDbSrc = sqlite3SchemaToIndex(pParse->db, pSrc->pSchema);
iDbSrc = sqlite3SchemaToIndex(db, pSrc->pSchema);
v = sqlite3GetVdbe(pParse);
sqlite3CodeVerifySchema(pParse, iDbSrc);
iSrc = pParse->nTab++;
@@ -1937,14 +1938,18 @@ static int xferOptimization(
regRowid = sqlite3GetTempReg(pParse);
sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
assert( HasRowid(pDest) || destHasUniqueIdx );
if( (pDest->iPKey<0 && pDest->pIndex!=0) /* (1) */
if( (db->flags & SQLITE_Vacuum)==0 && (
(pDest->iPKey<0 && pDest->pIndex!=0) /* (1) */
|| destHasUniqueIdx /* (2) */
|| (onError!=OE_Abort && onError!=OE_Rollback) /* (3) */
){
)){
/* In some circumstances, we are able to run the xfer optimization
** only if the destination table is initially empty. This code makes
** that determination. Conditions under which the destination must
** be empty:
** only if the destination table is initially empty. Unless the
** SQLITE_Vacuum flag is set, this block generates code to make
** that determination. If SQLITE_Vacuum is set, then the destination
** table is always empty.
**
** Conditions under which the destination must be empty:
**
** (1) There is no INTEGER PRIMARY KEY but there are indices.
** (If the destination is not initially empty, the rowid fields
@@ -1987,6 +1992,7 @@ static int xferOptimization(
sqlite3TableLock(pParse, iDbSrc, pSrc->tnum, 0, pSrc->zName);
}
for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
u8 useSeekResult = 0;
for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
}
@@ -2000,7 +2006,33 @@ static int xferOptimization(
VdbeComment((v, "%s", pDestIdx->zName));
addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
sqlite3VdbeAddOp2(v, OP_RowKey, iSrc, regData);
if( db->flags & SQLITE_Vacuum ){
/* This INSERT command is part of a VACUUM operation, which guarantees
** that the destination table is empty. If all indexed columns use
** collation sequence BINARY, then it can also be assumed that the
** index will be populated by inserting keys in strictly sorted
** order. In this case, instead of seeking within the b-tree as part
** of every OP_IdxInsert opcode, an OP_Last is added before the
** OP_IdxInsert to seek to the point within the b-tree where each key
** should be inserted. This is faster.
**
** If any of the indexed columns use a collation sequence other than
** BINARY, this optimization is disabled. This is because the user
** might change the definition of a collation sequence and then run
** a VACUUM command. In that case keys may not be written in strictly
** sorted order. */
int i;
for(i=0; i<pSrcIdx->nColumn; i++){
char *zColl = pSrcIdx->azColl[i];
if( zColl && sqlite3_stricmp("BINARY", zColl) ) break;
}
if( i==pSrcIdx->nColumn ){
useSeekResult = OPFLAG_USESEEKRESULT;
sqlite3VdbeAddOp3(v, OP_Last, iDest, 0, -1);
}
}
sqlite3VdbeAddOp3(v, OP_IdxInsert, iDest, regData, 1);
sqlite3VdbeChangeP5(v, useSeekResult);
sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
sqlite3VdbeJumpHere(v, addr1);
sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);