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Add the SQLITE_CHANGESETAPPLY_IGNORENOOP flag, which may be passed to sqlite3changeset_apply_v2() to have it ignore changes that would be no-ops if applied to the database (e.g. deleting a row that has already been deleted), instead of considering them conflicts.

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FossilOrigin-Name: cb023fe28560ce0f8c2fd48042553fcdb9db81eba9552be75165de0d46a2645c
This commit is contained in:
dan
2023-03-08 18:03:04 +00:00
parent 7ba63831f8
commit 975f2062da
15 changed files with 364 additions and 227 deletions
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131
ext/session/sqlite3session.c
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@ -2113,9 +2113,10 @@ static void sessionAppendStr(
int *pRc
){
int nStr = sqlite3Strlen30(zStr);
if( 0==sessionBufferGrow(p, nStr, pRc) ){
if( 0==sessionBufferGrow(p, nStr+1, pRc) ){
memcpy(&p->aBuf[p->nBuf], zStr, nStr);
p->nBuf += nStr;
p->aBuf[p->nBuf] = 0x00;
}
}
@ -2137,6 +2138,27 @@ static void sessionAppendInteger(
sessionAppendStr(p, aBuf, pRc);
}
static void sessionAppendPrintf(
SessionBuffer *p, /* Buffer to append to */
int *pRc,
const char *zFmt,
...
){
if( *pRc==SQLITE_OK ){
char *zApp = 0;
va_list ap;
va_start(ap, zFmt);
zApp = sqlite3_vmprintf(zFmt, ap);
if( zApp==0 ){
*pRc = SQLITE_NOMEM;
}else{
sessionAppendStr(p, zApp, pRc);
}
va_end(ap);
sqlite3_free(zApp);
}
}
/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is
** called. Otherwise, append the string zStr enclosed in quotes (") and
@ -2151,7 +2173,7 @@ static void sessionAppendIdent(
const char *zStr, /* String to quote, escape and append */
int *pRc /* IN/OUT: Error code */
){
int nStr = sqlite3Strlen30(zStr)*2 + 2 + 1;
int nStr = sqlite3Strlen30(zStr)*2 + 2 + 2;
if( 0==sessionBufferGrow(p, nStr, pRc) ){
char *zOut = (char *)&p->aBuf[p->nBuf];
const char *zIn = zStr;
@ -2162,6 +2184,7 @@ static void sessionAppendIdent(
}
*zOut++ = '"';
p->nBuf = (int)((u8 *)zOut - p->aBuf);
p->aBuf[p->nBuf] = 0x00;
}
}
@ -2386,10 +2409,17 @@ static int sessionAppendDelete(
** Formulate and prepare a SELECT statement to retrieve a row from table
** zTab in database zDb based on its primary key. i.e.
**
** SELECT * FROM zDb.zTab WHERE pk1 = ? AND pk2 = ? AND ...
** SELECT *, <noop-test> FROM zDb.zTab WHERE (pk1, pk2,...) IS (?1, ?2,...)
**
** where <noop-test> is:
**
** 1 AND (?A OR ?1 IS <column>) AND ...
**
** for each non-pk <column>.
*/
static int sessionSelectStmt(
sqlite3 *db, /* Database handle */
int bIgnoreNoop,
const char *zDb, /* Database name */
const char *zTab, /* Table name */
int nCol, /* Number of columns in table */
@ -2399,8 +2429,51 @@ static int sessionSelectStmt(
){
int rc = SQLITE_OK;
char *zSql = 0;
const char *zSep = "";
const char *zCols = "*";
int nSql = -1;
int i;
SessionBuffer nooptest = {0, 0, 0};
SessionBuffer pkfield = {0, 0, 0};
SessionBuffer pkvar = {0, 0, 0};
sessionAppendStr(&nooptest, ", 1", &rc);
if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){
sessionAppendStr(&nooptest, " AND (?6 OR ?3 IS stat)", &rc);
sessionAppendStr(&pkfield, "tbl, idx", &rc);
sessionAppendStr(&pkvar,
"?1, (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", &rc
);
zCols = "tbl, ?2, stat";
}else{
for(i=0; i<nCol; i++){
if( abPK[i] ){
sessionAppendStr(&pkfield, zSep, &rc);
sessionAppendStr(&pkvar, zSep, &rc);
zSep = ", ";
sessionAppendIdent(&pkfield, azCol[i], &rc);
sessionAppendPrintf(&pkvar, &rc, "?%d", i+1);
}else{
sessionAppendPrintf(&nooptest, &rc,
" AND (?%d OR ?%d IS %w.%w)", i+1+nCol, i+1, zTab, azCol[i]
);
}
}
}
if( rc==SQLITE_OK ){
zSql = sqlite3_mprintf(
"SELECT %s%s FROM %Q.%Q WHERE (%s) IS (%s)",
zCols, (bIgnoreNoop ? (char*)nooptest.aBuf : ""),
zDb, zTab, (char*)pkfield.aBuf, (char*)pkvar.aBuf
);
if( zSql==0 ) rc = SQLITE_NOMEM;
}
#if 0
if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){
zSql = sqlite3_mprintf(
"SELECT tbl, ?2, stat FROM %Q.sqlite_stat1 WHERE tbl IS ?1 AND "
@ -2408,7 +2481,6 @@ static int sessionSelectStmt(
);
if( zSql==0 ) rc = SQLITE_NOMEM;
}else{
int i;
const char *zSep = "";
SessionBuffer buf = {0, 0, 0};
@ -2429,11 +2501,15 @@ static int sessionSelectStmt(
zSql = (char*)buf.aBuf;
nSql = buf.nBuf;
}
#endif
if( rc==SQLITE_OK ){
rc = sqlite3_prepare_v2(db, zSql, nSql, ppStmt, 0);
}
sqlite3_free(zSql);
sqlite3_free(nooptest.aBuf);
sqlite3_free(pkfield.aBuf);
sqlite3_free(pkvar.aBuf);
return rc;
}
@ -2593,7 +2669,8 @@ static int sessionGenerateChangeset(
/* Build and compile a statement to execute: */
if( rc==SQLITE_OK ){
rc = sessionSelectStmt(
db, pSession->zDb, zName, nCol, azCol, abPK, &pSel);
db, 0, pSession->zDb, zName, nCol, azCol, abPK, &pSel
);
}
nNoop = buf.nBuf;
@ -3782,6 +3859,7 @@ struct SessionApplyCtx {
SessionBuffer rebase; /* Rebase information (if any) here */
u8 bRebaseStarted; /* If table header is already in rebase */
u8 bRebase; /* True to collect rebase information */
u8 bIgnoreNoop; /* True to ignore no-op conflicts */
};
/* Number of prepared UPDATE statements to cache. */
@ -4032,8 +4110,9 @@ static int sessionSelectRow(
const char *zTab, /* Table name */
SessionApplyCtx *p /* Session changeset-apply context */
){
return sessionSelectStmt(
db, "main", zTab, p->nCol, p->azCol, p->abPK, &p->pSelect);
return sessionSelectStmt(db, p->bIgnoreNoop,
"main", zTab, p->nCol, p->azCol, p->abPK, &p->pSelect
);
}
/*
@ -4192,20 +4271,33 @@ static int sessionBindRow(
*/
static int sessionSeekToRow(
sqlite3_changeset_iter *pIter, /* Changeset iterator */
u8 *abPK, /* Primary key flags array */
sqlite3_stmt *pSelect /* SELECT statement from sessionSelectRow() */
SessionApplyCtx *p
){
sqlite3_stmt *pSelect = p->pSelect;
int rc; /* Return code */
int nCol; /* Number of columns in table */
int op; /* Changset operation (SQLITE_UPDATE etc.) */
const char *zDummy; /* Unused */
sqlite3_clear_bindings(pSelect);
sqlite3changeset_op(pIter, &zDummy, &nCol, &op, 0);
rc = sessionBindRow(pIter,
op==SQLITE_INSERT ? sqlite3changeset_new : sqlite3changeset_old,
nCol, abPK, pSelect
nCol, p->abPK, pSelect
);
if( op!=SQLITE_DELETE && p->bIgnoreNoop ){
int ii;
for(ii=0; rc==SQLITE_OK && ii<nCol; ii++){
if( p->abPK[ii]==0 ){
sqlite3_value *pVal = 0;
sqlite3changeset_new(pIter, ii, &pVal);
sqlite3_bind_int(pSelect, ii+1+nCol, (pVal==0));
if( pVal ) rc = sessionBindValue(pSelect, ii+1, pVal);
}
}
}
if( rc==SQLITE_OK ){
rc = sqlite3_step(pSelect);
if( rc!=SQLITE_ROW ) rc = sqlite3_reset(pSelect);
@ -4320,16 +4412,22 @@ static int sessionConflictHandler(
/* Bind the new.* PRIMARY KEY values to the SELECT statement. */
if( pbReplace ){
rc = sessionSeekToRow(pIter, p->abPK, p->pSelect);
rc = sessionSeekToRow(pIter, p);
}else{
rc = SQLITE_OK;
}
if( rc==SQLITE_ROW ){
/* There exists another row with the new.* primary key. */
pIter->pConflict = p->pSelect;
res = xConflict(pCtx, eType, pIter);
pIter->pConflict = 0;
if( p->bIgnoreNoop
&& sqlite3_column_int(p->pSelect, sqlite3_column_count(p->pSelect)-1)
){
res = SQLITE_CHANGESET_OMIT;
}else{
pIter->pConflict = p->pSelect;
res = xConflict(pCtx, eType, pIter);
pIter->pConflict = 0;
}
rc = sqlite3_reset(p->pSelect);
}else if( rc==SQLITE_OK ){
if( p->bDeferConstraints && eType==SQLITE_CHANGESET_CONFLICT ){
@ -4437,7 +4535,7 @@ static int sessionApplyOneOp(
sqlite3_step(p->pDelete);
rc = sqlite3_reset(p->pDelete);
if( rc==SQLITE_OK && sqlite3_changes(p->db)==0 ){
if( rc==SQLITE_OK && sqlite3_changes(p->db)==0 && p->bIgnoreNoop==0 ){
rc = sessionConflictHandler(
SQLITE_CHANGESET_DATA, p, pIter, xConflict, pCtx, pbRetry
);
@ -4494,7 +4592,7 @@ static int sessionApplyOneOp(
/* Check if there is a conflicting row. For sqlite_stat1, this needs
** to be done using a SELECT, as there is no PRIMARY KEY in the
** database schema to throw an exception if a duplicate is inserted. */
rc = sessionSeekToRow(pIter, p->abPK, p->pSelect);
rc = sessionSeekToRow(pIter, p);
if( rc==SQLITE_ROW ){
rc = SQLITE_CONSTRAINT;
sqlite3_reset(p->pSelect);
@ -4671,6 +4769,7 @@ static int sessionChangesetApply(
memset(&sApply, 0, sizeof(sApply));
sApply.bRebase = (ppRebase && pnRebase);
sApply.bInvertConstraints = !!(flags & SQLITE_CHANGESETAPPLY_INVERT);
sApply.bIgnoreNoop = !!(flags & SQLITE_CHANGESETAPPLY_IGNORENOOP);
sqlite3_mutex_enter(sqlite3_db_mutex(db));
if( (flags & SQLITE_CHANGESETAPPLY_NOSAVEPOINT)==0 ){
rc = sqlite3_exec(db, "SAVEPOINT changeset_apply", 0, 0, 0);