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Work toward reducing the incremental size of an ExprList object to 24-byte

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per entry, from 32-bytes (on a 64-bit machine).  This helps the new
mini-lookaside allocator to run better by avoiding excessive reallocs.
The current change mostly works, but still has a few loose ends to tie up.
This check-in is merely a snapshot to save my work.

FossilOrigin-Name: fdda76cfb01bf2b19522ac4558b443634d28a69b0828677c42682b645eae1f3b
This commit is contained in:
drh 2019-12-12 22:11:33 +00:00
parent c947d6a4dc
commit cbb9da337e
6 changed files with 54 additions and 39 deletions
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23
manifest
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@ -1,5 +1,5 @@
C Fix\san\sissue\swhere\smalloc\scould\sbe\sused\sto\sfulfill\sa\ssmall\sallocation\swhen\sa\slarge\slookaside\sslot\scould\shave\sbeeen\sused\sinstead.
D 2019-12-12T20:39:47.705
C Work\stoward\sreducing\sthe\sincremental\ssize\sof\san\sExprList\sobject\sto\s24-byte\nper\sentry,\sfrom\s32-bytes\s(on\sa\s64-bit\smachine).\s\sThis\shelps\sthe\snew\nmini-lookaside\sallocator\sto\srun\sbetter\sby\savoiding\sexcessive\sreallocs.\nThe\scurrent\schange\smostly\sworks,\sbut\sstill\shas\sa\sfew\sloose\sends\sto\stie\sup.\nThis\scheck-in\sis\smerely\sa\ssnapshot\sto\ssave\smy\swork.
D 2019-12-12T22:11:33.445
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@ -479,7 +479,7 @@ F src/date.c e1d8ac7102f3f283e63e13867acb0efa33861cf34f0faf4cdbaf9fa7a1eb7041
F src/dbpage.c 135eb3b5e74f9ef74bde5cec2571192c90c86984fa534c88bf4a055076fa19b7
F src/dbstat.c 6c407e549406c10fde9ac3987f6d734459205239ad370369bc5fcd683084a4fa
F src/delete.c a5c59b9c0251cf7682bc52af0d64f09b1aefc6781a63592c8f1136f7b73c66e4
F src/expr.c eefc9abca2d8bb8b2cad063dd65c764e5264f1d80c83268a9debcfff2f7a32bb
F src/expr.c 828bc6ae0c15e60a5b0a5fb17ddf98fb3f9a52752fb34cbbdc15ea4868afcf90
F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
F src/fkey.c 92a248ec0fa4ed8ab60c98d9b188ce173aaf218f32e7737ba77deb2a684f9847
F src/func.c ed33e38cd642058182a31a3f518f2e34f4bbe53aa483335705c153c4d3e50b12
@ -525,14 +525,14 @@ F src/pragma.h ec3b31eac9b1df040f1cc8cb3d89bc06605c3b4cb3d76f833de8d6d6c3f77f04
F src/prepare.c 6049beb71385f017af6fc320d2c75a4e50b75e280c54232442b785fbb83df057
F src/printf.c 9be6945837c839ba57837b4bc3af349eba630920fa5532aa518816defe42a7d4
F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
F src/resolve.c d703803412770e100be0d79adc4d0b52a99c49715ba8d4a736e503ee5526d473
F src/resolve.c fc7bed8f23355db3af73859b4af42af4ee2f7cf3467aa5e242321575203e2896
F src/rowset.c d977b011993aaea002cab3e0bb2ce50cf346000dff94e944d547b989f4b1fe93
F src/select.c 39a9e180a2fdf738f3a02977684bc4cad3f5ff8d9f949f2aa48eef2ce5ff29aa
F src/select.c b5702ca6b2f215bb8bee27f591d72dfd52250a680b5fa11871a1a7be69dff758
F src/shell.c.in 4a3a9e1c11847b1904f2b01d087af1c052f660902755abab457cab1756817ded
F src/sqlite.h.in 2a23e8161775253d9cf383c2c6aa559005dc787d350dcb0be67a6c4cc3bd1d19
F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
F src/sqlite3ext.h 72af51aa4e912e14cd495fb6e7fac65f0940db80ed950d90911aff292cc47ce2
F src/sqliteInt.h ebb8c7e6439dc4cd6abad9fed0d01751160115328c8670b733505d7c5c6b12a4
F src/sqliteInt.h 5be56f6523e0980b4ab66d6420e11dbe66c060c7b2e20aa28344fd67457cbe32
F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
F src/status.c 0fe55b92810509eac821ded2e177e1da944a78cdcdfec7813ad1d6b36d6d667e
F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@ -1852,7 +1852,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
P d3783357f8fa76c42a86f12b214522f0388c37773c36ab8c5ce0623abbc4436a
R 419a6defa175975b0c1f1ba26db0be60
U numist
Z c7e98609c62b97e8952867680421d71f
P 611020e3378f4c81c277cccd84807ae51a816bbab6c3d887c91c5e5af3b5225f
R 162199bc809f1616aa82013813cc7e3c
T *branch * exprlist-size-reduction
T *sym-exprlist-size-reduction *
T -sym-mini-lookaside-take-2 *
U drh
Z 2404f597cd0a4292958003b4ec4cbb04

2
manifest.uuid
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@ -1 +1 @@
611020e3378f4c81c277cccd84807ae51a816bbab6c3d887c91c5e5af3b5225f
fdda76cfb01bf2b19522ac4558b443634d28a69b0828677c42682b645eae1f3b

10
src/expr.c
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@ -1437,11 +1437,10 @@ ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p, int flags){
}
}
pItem->zEName = sqlite3DbStrDup(db, pOldItem->zEName);
pItem->zSpan = sqlite3DbStrDup(db, pOldItem->zSpan);
pItem->sortFlags = pOldItem->sortFlags;
pItem->eEName = pOldItem->eEName;
pItem->done = 0;
pItem->bNulls = pOldItem->bNulls;
pItem->bSpanIsTab = pOldItem->bSpanIsTab;
pItem->bSorterRef = pOldItem->bSorterRef;
pItem->u = pOldItem->u;
}
@ -1773,8 +1772,10 @@ void sqlite3ExprListSetSpan(
if( pList ){
struct ExprList_item *pItem = &pList->a[pList->nExpr-1];
assert( pList->nExpr>0 );
sqlite3DbFree(db, pItem->zSpan);
pItem->zSpan = sqlite3DbSpanDup(db, zStart, zEnd);
if( pItem->zEName==0 ){
pItem->zEName = sqlite3DbSpanDup(db, zStart, zEnd);
pItem->eEName = ENAME_SPAN;
}
}
}
@ -1805,7 +1806,6 @@ static SQLITE_NOINLINE void exprListDeleteNN(sqlite3 *db, ExprList *pList){
do{
sqlite3ExprDelete(db, pItem->pExpr);
sqlite3DbFree(db, pItem->zEName);
sqlite3DbFree(db, pItem->zSpan);
pItem++;
}while( --i>0 );
sqlite3DbFreeNN(db, pList);

2
src/resolve.c
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@ -267,7 +267,7 @@ static int lookupName(
int hit = 0;
pEList = pItem->pSelect->pEList;
for(j=0; j<pEList->nExpr; j++){
if( sqlite3MatchSpanName(pEList->a[j].zSpan, zCol, zTab, zDb) ){
if( sqlite3MatchSpanName(pEList->a[j].zEName, zCol, zTab, zDb) ){
cnt++;
cntTab = 2;
pMatch = pItem;

26
src/select.c
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@ -1539,7 +1539,7 @@ static void generateSortTail(
iRead = iCol--;
}
sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iRead, regRow+i);
VdbeComment((v, "%s", aOutEx[i].zEName?aOutEx[i].zEName:aOutEx[i].zSpan));
VdbeComment((v, "%s", aOutEx[i].zEName));
}
}
switch( eDest ){
@ -1873,7 +1873,7 @@ static void generateColumnNames(
assert( p!=0 );
assert( p->op!=TK_AGG_COLUMN ); /* Agg processing has not run yet */
assert( p->op!=TK_COLUMN || p->y.pTab!=0 ); /* Covering idx not yet coded */
if( pEList->a[i].zEName ){
if( pEList->a[i].zEName && pEList->a[i].eEName==ENAME_NAME ){
/* An AS clause always takes first priority */
char *zName = pEList->a[i].zEName;
sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
@ -1897,7 +1897,7 @@ static void generateColumnNames(
sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, SQLITE_TRANSIENT);
}
}else{
const char *z = pEList->a[i].zSpan;
const char *z = pEList->a[i].zEName;
z = z==0 ? sqlite3MPrintf(db, "column%d", i+1) : sqlite3DbStrDup(db, z);
sqlite3VdbeSetColName(v, i, COLNAME_NAME, z, SQLITE_DYNAMIC);
}
@ -1959,7 +1959,7 @@ int sqlite3ColumnsFromExprList(
for(i=0, pCol=aCol; i<nCol && !db->mallocFailed; i++, pCol++){
/* Get an appropriate name for the column
*/
if( (zName = pEList->a[i].zEName)!=0 ){
if( (zName = pEList->a[i].zEName)!=0 && pEList->a[i].eEName==ENAME_NAME ){
/* If the column contains an "AS <name>" phrase, use <name> as the name */
}else{
Expr *pColExpr = sqlite3ExprSkipCollateAndLikely(pEList->a[i].pExpr);
@ -1979,7 +1979,7 @@ int sqlite3ColumnsFromExprList(
zName = pColExpr->u.zToken;
}else{
/* Use the original text of the column expression as its name */
zName = pEList->a[i].zSpan;
zName = pEList->a[i].zEName;
}
}
if( zName ){
@ -5004,9 +5004,8 @@ static int selectExpander(Walker *pWalker, Select *p){
pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr);
if( pNew ){
pNew->a[pNew->nExpr-1].zEName = a[k].zEName;
pNew->a[pNew->nExpr-1].zSpan = a[k].zSpan;
pNew->a[pNew->nExpr-1].eEName = a[k].eEName;
a[k].zEName = 0;
a[k].zSpan = 0;
}
a[k].pExpr = 0;
}else{
@ -5045,7 +5044,7 @@ static int selectExpander(Walker *pWalker, Select *p){
assert( zName );
if( zTName && pSub
&& sqlite3MatchSpanName(pSub->pEList->a[j].zSpan, 0, zTName, 0)==0
&& sqlite3MatchSpanName(pSub->pEList->a[j].zEName, 0, zTName, 0)==0
){
continue;
}
@ -5098,15 +5097,16 @@ static int selectExpander(Walker *pWalker, Select *p){
sqlite3ExprListSetName(pParse, pNew, &sColname, 0);
if( pNew && (p->selFlags & SF_NestedFrom)!=0 ){
struct ExprList_item *pX = &pNew->a[pNew->nExpr-1];
sqlite3DbFree(db, pX->zEName);
if( pSub ){
pX->zSpan = sqlite3DbStrDup(db, pSub->pEList->a[j].zSpan);
testcase( pX->zSpan==0 );
pX->zEName = sqlite3DbStrDup(db, pSub->pEList->a[j].zEName);
testcase( pX->zEName==0 );
}else{
pX->zSpan = sqlite3MPrintf(db, "%s.%s.%s",
pX->zEName = sqlite3MPrintf(db, "%s.%s.%s",
zSchemaName, zTabName, zColname);
testcase( pX->zSpan==0 );
testcase( pX->zEName==0 );
}
pX->bSpanIsTab = 1;
pX->eEName = ENAME_TAB;
}
sqlite3DbFree(db, zToFree);
}

30
src/sqliteInt.h
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@ -2650,23 +2650,28 @@ struct Expr {
** also be used as the argument to a function, in which case the a.zName
** field is not used.
**
** By default the Expr.zSpan field holds a human-readable description of
** the expression that is used in the generation of error messages and
** column labels. In this case, Expr.zSpan is typically the text of a
** column expression as it exists in a SELECT statement. However, if
** the bSpanIsTab flag is set, then zSpan is overloaded to mean the name
** of the result column in the form: DATABASE.TABLE.COLUMN. This later
** form is used for name resolution with nested FROM clauses.
** In order to try to keep memory usage down, the Expr.a.zEName field
** is used for multiple purposes:
**
** bNameIsTab bNameIsSpan Usage
** ---------- ----------- -------------------------
** false false (1) the AS of result set column
** (2) COLUMN= of an UPDATE
**
** true false DB.TABLE.NAME used to resolve names
** of subqueries
**
** false true Text of the original result set
** expression.
*/
struct ExprList {
int nExpr; /* Number of expressions on the list */
struct ExprList_item { /* For each expression in the list */
Expr *pExpr; /* The parse tree for this expression */
char *zEName; /* Token associated with this expression */
char *zSpan; /* Original text of the expression */
u8 sortFlags; /* Mask of KEYINFO_ORDER_* flags */
unsigned eEName :2; /* Meaning of zEName */
unsigned done :1; /* A flag to indicate when processing is finished */
unsigned bSpanIsTab :1; /* zSpan holds DB.TABLE.COLUMN */
unsigned reusable :1; /* Constant expression is reusable */
unsigned bSorterRef :1; /* Defer evaluation until after sorting */
unsigned bNulls: 1; /* True if explicit "NULLS FIRST/LAST" */
@ -2680,6 +2685,13 @@ struct ExprList {
} a[1]; /* One slot for each expression in the list */
};
/*
** Allowed values for Expr.a.eEName
*/
#define ENAME_NAME 0 /* The AS clause of a result set */
#define ENAME_SPAN 1 /* Complete text of the result set expression */
#define ENAME_TAB 2 /* "DB.TABLE.NAME" for the result set */
/*
** An instance of this structure can hold a simple list of identifiers,
** such as the list "a,b,c" in the following statements: