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Sorting is now done using a sorting index rather than loading the entire

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result set into memory and doing a merge sort.  The old merge sort technique
was a carry-over from SQLite version 1.  The new method uses a bounded amount
of memory and scales to much larger result sets.  There are still errors:
some 39 regression tests fail. (CVS 2653)

FossilOrigin-Name: 09db0a24241f9248584250d1728117b8a3159626
This commit is contained in:
drh
2005-09-01 03:07:44 +00:00
parent dece1a8464
commit 0342b1f542
9 changed files with 192 additions and 338 deletions
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22
src/sqliteInt.h
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@@ -11,7 +11,7 @@
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.406 2005/08/30 00:54:03 drh Exp $
** @(#) $Id: sqliteInt.h,v 1.407 2005/09/01 03:07:44 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_
@@ -886,13 +886,13 @@ struct Expr {
struct ExprList {
int nExpr; /* Number of expressions on the list */
int nAlloc; /* Number of entries allocated below */
int iTab; /* VDBE Cursor associated with this ExprList */
struct ExprList_item {
Expr *pExpr; /* The list of expressions */
char *zName; /* Token associated with this expression */
u8 sortOrder; /* 1 for DESC or 0 for ASC */
u8 isAgg; /* True if this is an aggregate like count(*) */
u8 done; /* A flag to indicate when processing is finished */
u8 orderByDup[2]; /* Corresponding term in OrderBy/GroupBy clause */
} *a; /* One entry for each expression */
};
@@ -1045,23 +1045,35 @@ struct NameContext {
** limit and nOffset to the value of the offset (or 0 if there is not
** offset). But later on, nLimit and nOffset become the memory locations
** in the VDBE that record the limit and offset counters.
**
** addrOpenVirt[] entries contain the address of OP_OpenVirtual opcodes.
** These addresses must be stored so that we can go back and fill in
** the P3_KEYINFO and P2 parameters later. Neither the KeyInfo nor
** the number of columns in P2 can be computed at the same time
** as the OP_OpenVirtual instruction is coded because not
** enough information about the compound query is known at that point.
** The KeyInfo for addrOpenVirt[0] and [1] contains collating sequences
** for the result set. The KeyInfo for addrOpenVirt[2] contains collating
** sequences for the ORDER BY clause.
*/
struct Select {
ExprList *pEList; /* The fields of the result */
u8 op; /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
u8 isDistinct; /* True if the DISTINCT keyword is present */
u8 isResolved; /* True once sqlite3SelectResolve() has run. */
u8 isAgg; /* True if this is an aggregate query */
u8 usesVirt; /* True if uses an OpenVirtual opcode */
SrcList *pSrc; /* The FROM clause */
Expr *pWhere; /* The WHERE clause */
ExprList *pGroupBy; /* The GROUP BY clause */
Expr *pHaving; /* The HAVING clause */
ExprList *pOrderBy; /* The ORDER BY clause */
Select *pPrior; /* Prior select in a compound select statement */
Select *pRightmost; /* Right-most select in a compound select statement */
Expr *pLimit; /* LIMIT expression. NULL means not used. */
Expr *pOffset; /* OFFSET expression. NULL means not used. */
int iLimit, iOffset; /* Memory registers holding LIMIT & OFFSET counters */
IdList **ppOpenVirtual;/* OP_OpenVirtual addresses used by multi-selects */
u8 isResolved; /* True once sqlite3SelectResolve() has run. */
u8 isAgg; /* True if this is an aggregate query */
int addrOpenVirt[3]; /* OP_OpenVirtual opcodes related to this select */
};
/*