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Reorder the fields in private structures in an effort to reduce alignment

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gaps and thus make the structures smaller, and to put frequently accessed
fields first.  Also update some obsolete comments.  Valgrind shows a very
slight performance improvement.

FossilOrigin-Name: 378a1d13af4a6f4cb2bfa65944b3b0d444b9f21c
This commit is contained in:
drh
2011-01-07 02:50:40 +00:00
parent b7787eef7a
commit 2e5de2f2b3
5 changed files with 54 additions and 78 deletions
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90
src/vdbeInt.h
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@@ -39,16 +39,14 @@ typedef unsigned char Bool;
**
** Every cursor that the virtual machine has open is represented by an
** instance of the following structure.
**
** If the VdbeCursor.isTriggerRow flag is set it means that this cursor is
** really a single row that represents the NEW or OLD pseudo-table of
** a row trigger. The data for the row is stored in VdbeCursor.pData and
** the rowid is in VdbeCursor.iKey.
*/
struct VdbeCursor {
BtCursor *pCursor; /* The cursor structure of the backend */
Btree *pBt; /* Separate file holding temporary table */
KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
int iDb; /* Index of cursor database in db->aDb[] (or -1) */
i64 lastRowid; /* Last rowid from a Next or NextIdx operation */
int pseudoTableReg; /* Register holding pseudotable content. */
int nField; /* Number of fields in the header */
Bool zeroed; /* True if zeroed out and ready for reuse */
Bool rowidIsValid; /* True if lastRowid is valid */
Bool atFirst; /* True if pointing to first entry */
@@ -58,14 +56,11 @@ struct VdbeCursor {
Bool isTable; /* True if a table requiring integer keys */
Bool isIndex; /* True if an index containing keys only - no data */
Bool isOrdered; /* True if the underlying table is BTREE_UNORDERED */
i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
Btree *pBt; /* Separate file holding temporary table */
int pseudoTableReg; /* Register holding pseudotable content. */
KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
int nField; /* Number of fields in the header */
i64 seqCount; /* Sequence counter */
sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */
const sqlite3_module *pModule; /* Module for cursor pVtabCursor */
i64 seqCount; /* Sequence counter */
i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
i64 lastRowid; /* Last rowid from a Next or NextIdx operation */
/* Result of last sqlite3BtreeMoveto() done by an OP_NotExists or
** OP_IsUnique opcode on this cursor. */
@@ -137,25 +132,19 @@ struct VdbeFrame {
/*
** Internally, the vdbe manipulates nearly all SQL values as Mem
** structures. Each Mem struct may cache multiple representations (string,
** integer etc.) of the same value. A value (and therefore Mem structure)
** has the following properties:
**
** Each value has a manifest type. The manifest type of the value stored
** in a Mem struct is returned by the MemType(Mem*) macro. The type is
** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or
** SQLITE_BLOB.
** integer etc.) of the same value.
*/
struct Mem {
sqlite3 *db; /* The associated database connection */
char *z; /* String or BLOB value */
double r; /* Real value */
union {
i64 i; /* Integer value. */
i64 i; /* Integer value used when MEM_Int is set in flags */
int nZero; /* Used when bit MEM_Zero is set in flags */
FuncDef *pDef; /* Used only when flags==MEM_Agg */
RowSet *pRowSet; /* Used only when flags==MEM_RowSet */
VdbeFrame *pFrame; /* Used when flags==MEM_Frame */
} u;
double r; /* Real value */
sqlite3 *db; /* The associated database connection */
char *z; /* String or BLOB value */
int n; /* Number of characters in string value, excluding '\0' */
u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
@@ -179,9 +168,6 @@ struct Mem {
** database (see below for exceptions). If the MEM_Term flag is also
** set, then the string is nul terminated. The MEM_Int and MEM_Real
** flags may coexist with the MEM_Str flag.
**
** Multiple of these values can appear in Mem.flags. But only one
** at a time can appear in Mem.type.
*/
#define MEM_Null 0x0001 /* Value is NULL */
#define MEM_Str 0x0002 /* Value is a string */
@@ -264,23 +250,11 @@ struct sqlite3_context {
CollSeq *pColl; /* Collating sequence */
};
/*
** A Set structure is used for quick testing to see if a value
** is part of a small set. Sets are used to implement code like
** this:
** x.y IN ('hi','hoo','hum')
*/
typedef struct Set Set;
struct Set {
Hash hash; /* A set is just a hash table */
HashElem *prev; /* Previously accessed hash elemen */
};
/*
** An instance of the virtual machine. This structure contains the complete
** state of the virtual machine.
**
** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile()
** The "sqlite3_stmt" structure pointer that is returned by sqlite3_prepare()
** is really a pointer to an instance of this structure.
**
** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
@@ -293,31 +267,31 @@ struct Set {
*/
struct Vdbe {
sqlite3 *db; /* The database connection that owns this statement */
Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
int nOp; /* Number of instructions in the program */
int nOpAlloc; /* Number of slots allocated for aOp[] */
Op *aOp; /* Space to hold the virtual machine's program */
int nLabel; /* Number of labels used */
int nLabelAlloc; /* Number of slots allocated in aLabel[] */
int *aLabel; /* Space to hold the labels */
Mem *aMem; /* The memory locations */
Mem **apArg; /* Arguments to currently executing user function */
Mem *aColName; /* Column names to return */
Mem *pResultSet; /* Pointer to an array of results */
int nMem; /* Number of memory locations currently allocated */
int nOp; /* Number of instructions in the program */
int nOpAlloc; /* Number of slots allocated for aOp[] */
int nLabel; /* Number of labels used */
int nLabelAlloc; /* Number of slots allocated in aLabel[] */
int *aLabel; /* Space to hold the labels */
u16 nResColumn; /* Number of columns in one row of the result set */
u16 nCursor; /* Number of slots in apCsr[] */
u32 magic; /* Magic number for sanity checking */
char *zErrMsg; /* Error message written here */
Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
VdbeCursor **apCsr; /* One element of this array for each open cursor */
u8 errorAction; /* Recovery action to do in case of an error */
u8 okVar; /* True if azVar[] has been initialized */
ynVar nVar; /* Number of entries in aVar[] */
Mem *aVar; /* Values for the OP_Variable opcode. */
char **azVar; /* Name of variables */
u32 magic; /* Magic number for sanity checking */
int nMem; /* Number of memory locations currently allocated */
Mem *aMem; /* The memory locations */
ynVar nVar; /* Number of entries in aVar[] */
u32 cacheCtr; /* VdbeCursor row cache generation counter */
int pc; /* The program counter */
int rc; /* Value to return */
char *zErrMsg; /* Error message written here */
u8 errorAction; /* Recovery action to do in case of an error */
u8 okVar; /* True if azVar[] has been initialized */
u8 explain; /* True if EXPLAIN present on SQL command */
u8 changeCntOn; /* True to update the change-counter */
u8 expired; /* True if the VM needs to be recompiled */
@@ -329,14 +303,16 @@ struct Vdbe {
u8 isPrepareV2; /* True if prepared with prepare_v2() */
int nChange; /* Number of db changes made since last reset */
int btreeMask; /* Bitmask of db->aDb[] entries referenced */
i64 startTime; /* Time when query started - used for profiling */
BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
int iStatement; /* Statement number (or 0 if has not opened stmt) */
int aCounter[3]; /* Counters used by sqlite3_stmt_status() */
char *zSql; /* Text of the SQL statement that generated this */
void *pFree; /* Free this when deleting the vdbe */
BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
#ifndef SQLITE_OMIT_TRACE
i64 startTime; /* Time when query started - used for profiling */
#endif
i64 nFkConstraint; /* Number of imm. FK constraints this VM */
i64 nStmtDefCons; /* Number of def. constraints when stmt started */
int iStatement; /* Statement number (or 0 if has not opened stmt) */
char *zSql; /* Text of the SQL statement that generated this */
void *pFree; /* Free this when deleting the vdbe */
#ifdef SQLITE_DEBUG
FILE *trace; /* Write an execution trace here, if not NULL */
#endif