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First cut at optimizing single-row updates to use a one-pass algorithm. (CVS 4973)

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FossilOrigin-Name: fba97f7874d723111e873d1470fc1a95e64f922d
This commit is contained in:
drh
2008-04-10 13:33:18 +00:00
parent 67ade0a2d0
commit 08c88eb0d3
7 changed files with 68 additions and 40 deletions
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22
src/update.c
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@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.175 2008/04/01 05:07:15 drh Exp $
** $Id: update.c,v 1.176 2008/04/10 13:33:18 drh Exp $
*/
#include "sqliteInt.h"
@@ -103,6 +103,7 @@ void sqlite3Update(
NameContext sNC; /* The name-context to resolve expressions in */
int iDb; /* Database containing the table being updated */
int j1; /* Addresses of jump instructions */
int okOnePass; /* True for one-pass algorithm without the FIFO */
#ifndef SQLITE_OMIT_TRIGGER
int isView; /* Trying to update a view */
@@ -341,13 +342,16 @@ void sqlite3Update(
/* Begin the database scan
*/
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0);
sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0,
WHERE_ONEPASS_DESIRED);
if( pWInfo==0 ) goto update_cleanup;
okOnePass = pWInfo->okOnePass;
/* Remember the rowid of every item to be updated.
*/
sqlite3VdbeAddOp2(v, IsVirtual(pTab) ? OP_VRowid : OP_Rowid,iCur,regOldRowid);
sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0);
sqlite3VdbeAddOp2(v, IsVirtual(pTab)?OP_VRowid:OP_Rowid, iCur, regOldRowid);
if( !okOnePass ) sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0);
/* End the database scan loop.
*/
@@ -367,7 +371,7 @@ void sqlite3Update(
** action, then we need to open all indices because we might need
** to be deleting some records.
*/
sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite);
if( !okOnePass ) sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite);
if( onError==OE_Replace ){
openAll = 1;
}else{
@@ -395,7 +399,13 @@ void sqlite3Update(
}
/* Top of the update loop */
addr = sqlite3VdbeAddOp2(v, OP_FifoRead, regOldRowid, 0);
if( okOnePass ){
int a1 = sqlite3VdbeAddOp1(v, OP_NotNull, regOldRowid);
addr = sqlite3VdbeAddOp0(v, OP_Goto);
sqlite3VdbeJumpHere(v, a1);
}else{
addr = sqlite3VdbeAddOp2(v, OP_FifoRead, regOldRowid, 0);
}
if( triggers_exist ){
int regRowid;