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

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

View File

@@ -414,12 +414,12 @@ struct BtShared {
u8 autoVacuum; /* True if auto-vacuum is enabled */
u8 incrVacuum; /* True if incr-vacuum is enabled */
#endif
u8 inTransaction; /* Transaction state */
u8 doNotUseWAL; /* If true, do not open write-ahead-log file */
u16 maxLocal; /* Maximum local payload in non-LEAFDATA tables */
u16 minLocal; /* Minimum local payload in non-LEAFDATA tables */
u16 maxLeaf; /* Maximum local payload in a LEAFDATA table */
u16 minLeaf; /* Minimum local payload in a LEAFDATA table */
u8 inTransaction; /* Transaction state */
u8 doNotUseWAL; /* If true, do not open write-ahead-log file */
u32 pageSize; /* Total number of bytes on a page */
u32 usableSize; /* Number of usable bytes on each page */
int nTransaction; /* Number of open transactions (read + write) */
@@ -446,8 +446,8 @@ struct BtShared {
*/
typedef struct CellInfo CellInfo;
struct CellInfo {
u8 *pCell; /* Pointer to the start of cell content */
i64 nKey; /* The key for INTKEY tables, or number of bytes in key */
u8 *pCell; /* Pointer to the start of cell content */
u32 nData; /* Number of bytes of data */
u32 nPayload; /* Total amount of payload */
u16 nHeader; /* Size of the cell content header in bytes */
@@ -489,20 +489,20 @@ struct BtCursor {
Pgno pgnoRoot; /* The root page of this tree */
sqlite3_int64 cachedRowid; /* Next rowid cache. 0 means not valid */
CellInfo info; /* A parse of the cell we are pointing at */
i64 nKey; /* Size of pKey, or last integer key */
void *pKey; /* Saved key that was cursor's last known position */
int skipNext; /* Prev() is noop if negative. Next() is noop if positive */
u8 wrFlag; /* True if writable */
u8 atLast; /* Cursor pointing to the last entry */
u8 validNKey; /* True if info.nKey is valid */
u8 eState; /* One of the CURSOR_XXX constants (see below) */
void *pKey; /* Saved key that was cursor's last known position */
i64 nKey; /* Size of pKey, or last integer key */
int skipNext; /* Prev() is noop if negative. Next() is noop if positive */
#ifndef SQLITE_OMIT_INCRBLOB
u8 isIncrblobHandle; /* True if this cursor is an incr. io handle */
Pgno *aOverflow; /* Cache of overflow page locations */
u8 isIncrblobHandle; /* True if this cursor is an incr. io handle */
#endif
i16 iPage; /* Index of current page in apPage */
MemPage *apPage[BTCURSOR_MAX_DEPTH]; /* Pages from root to current page */
u16 aiIdx[BTCURSOR_MAX_DEPTH]; /* Current index in apPage[i] */
MemPage *apPage[BTCURSOR_MAX_DEPTH]; /* Pages from root to current page */
};
/*