diff options
Diffstat (limited to 'third_party/sqlite/src/btreeInt.h')
| -rw-r--r-- | third_party/sqlite/src/btreeInt.h | 149 |
1 files changed, 81 insertions, 68 deletions
diff --git a/third_party/sqlite/src/btreeInt.h b/third_party/sqlite/src/btreeInt.h index 663a41e..239439b 100644 --- a/third_party/sqlite/src/btreeInt.h +++ b/third_party/sqlite/src/btreeInt.h @@ -9,7 +9,7 @@ ** May you share freely, never taking more than you give. ** ************************************************************************* -** $Id: btreeInt.h,v 1.30 2008/08/01 20:10:08 drh Exp $ +** $Id: btreeInt.h,v 1.52 2009/07/15 17:25:46 drh Exp $ ** ** This file implements a external (disk-based) database using BTrees. ** For a detailed discussion of BTrees, refer to @@ -71,6 +71,17 @@ ** 36 4 Number of freelist pages in the file ** 40 60 15 4-byte meta values passed to higher layers ** +** 40 4 Schema cookie +** 44 4 File format of schema layer +** 48 4 Size of page cache +** 52 4 Largest root-page (auto/incr_vacuum) +** 56 4 1=UTF-8 2=UTF16le 3=UTF16be +** 60 4 User version +** 64 4 Incremental vacuum mode +** 68 4 unused +** 72 4 unused +** 76 4 unused +** ** All of the integer values are big-endian (most significant byte first). ** ** The file change counter is incremented when the database is changed @@ -204,15 +215,6 @@ ** * zero or more pages numbers of leaves */ #include "sqliteInt.h" -#include "pager.h" -#include "btree.h" -#include "os.h" -#include <assert.h> - -/* Round up a number to the next larger multiple of 8. This is used -** to force 8-byte alignment on 64-bit architectures. -*/ -#define ROUND8(x) ((x+7)&~7) /* The following value is the maximum cell size assuming a maximum page @@ -271,7 +273,6 @@ typedef struct BtLock BtLock; */ struct MemPage { u8 isInit; /* True if previously initialized. MUST BE FIRST! */ - u8 idxShift; /* True if Cell indices have changed */ u8 nOverflow; /* Number of overflow cell bodies in aCell[] */ u8 intKey; /* True if intkey flag is set */ u8 leaf; /* True if leaf flag is set */ @@ -281,7 +282,6 @@ struct MemPage { u16 maxLocal; /* Copy of BtShared.maxLocal or BtShared.maxLeaf */ u16 minLocal; /* Copy of BtShared.minLocal or BtShared.minLeaf */ u16 cellOffset; /* Index in aData of first cell pointer */ - u16 idxParent; /* Index in parent of this node */ u16 nFree; /* Number of free bytes on the page */ u16 nCell; /* Number of cells on this page, local and ovfl */ u16 maskPage; /* Mask for page offset */ @@ -293,7 +293,6 @@ struct MemPage { u8 *aData; /* Pointer to disk image of the page data */ DbPage *pDbPage; /* Pager page handle */ Pgno pgno; /* Page number for this page */ - MemPage *pParent; /* The parent of this page. NULL for root */ }; /* @@ -303,6 +302,24 @@ struct MemPage { */ #define EXTRA_SIZE sizeof(MemPage) +/* +** A linked list of the following structures is stored at BtShared.pLock. +** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor +** is opened on the table with root page BtShared.iTable. Locks are removed +** from this list when a transaction is committed or rolled back, or when +** a btree handle is closed. +*/ +struct BtLock { + Btree *pBtree; /* Btree handle holding this lock */ + Pgno iTable; /* Root page of table */ + u8 eLock; /* READ_LOCK or WRITE_LOCK */ + BtLock *pNext; /* Next in BtShared.pLock list */ +}; + +/* Candidate values for BtLock.eLock */ +#define READ_LOCK 1 +#define WRITE_LOCK 2 + /* A Btree handle ** ** A database connection contains a pointer to an instance of @@ -331,8 +348,12 @@ struct Btree { u8 sharable; /* True if we can share pBt with another db */ u8 locked; /* True if db currently has pBt locked */ int wantToLock; /* Number of nested calls to sqlite3BtreeEnter() */ + int nBackup; /* Number of backup operations reading this btree */ Btree *pNext; /* List of other sharable Btrees from the same db */ Btree *pPrev; /* Back pointer of the same list */ +#ifndef SQLITE_OMIT_SHARED_CACHE + BtLock lock; /* Object used to lock page 1 */ +#endif }; /* @@ -362,37 +383,55 @@ struct Btree { ** may not be modified once it is initially set as long as nRef>0. ** The pSchema field may be set once under BtShared.mutex and ** thereafter is unchanged as long as nRef>0. +** +** isPending: +** +** If a BtShared client fails to obtain a write-lock on a database +** table (because there exists one or more read-locks on the table), +** the shared-cache enters 'pending-lock' state and isPending is +** set to true. +** +** The shared-cache leaves the 'pending lock' state when either of +** the following occur: +** +** 1) The current writer (BtShared.pWriter) concludes its transaction, OR +** 2) The number of locks held by other connections drops to zero. +** +** while in the 'pending-lock' state, no connection may start a new +** transaction. +** +** This feature is included to help prevent writer-starvation. */ struct BtShared { Pager *pPager; /* The page cache */ sqlite3 *db; /* Database connection currently using this Btree */ BtCursor *pCursor; /* A list of all open cursors */ MemPage *pPage1; /* First page of the database */ - u8 inStmt; /* True if we are in a statement subtransaction */ u8 readOnly; /* True if the underlying file is readonly */ u8 pageSizeFixed; /* True if the page size can no longer be changed */ #ifndef SQLITE_OMIT_AUTOVACUUM u8 autoVacuum; /* True if auto-vacuum is enabled */ u8 incrVacuum; /* True if incr-vacuum is enabled */ - Pgno nTrunc; /* Non-zero if the db will be truncated (incr vacuum) */ #endif u16 pageSize; /* Total number of bytes on a page */ u16 usableSize; /* Number of usable bytes on each page */ - int maxLocal; /* Maximum local payload in non-LEAFDATA tables */ - int minLocal; /* Minimum local payload in non-LEAFDATA tables */ - int maxLeaf; /* Maximum local payload in a LEAFDATA table */ - int minLeaf; /* Minimum local payload in a LEAFDATA table */ + 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 */ int nTransaction; /* Number of open transactions (read + write) */ void *pSchema; /* Pointer to space allocated by sqlite3BtreeSchema() */ void (*xFreeSchema)(void*); /* Destructor for BtShared.pSchema */ sqlite3_mutex *mutex; /* Non-recursive mutex required to access this struct */ - BusyHandler busyHdr; /* The busy handler for this btree */ + Bitvec *pHasContent; /* Set of pages moved to free-list this transaction */ #ifndef SQLITE_OMIT_SHARED_CACHE int nRef; /* Number of references to this structure */ BtShared *pNext; /* Next on a list of sharable BtShared structs */ BtLock *pLock; /* List of locks held on this shared-btree struct */ - Btree *pExclusive; /* Btree with an EXCLUSIVE lock on the whole db */ + Btree *pWriter; /* Btree with currently open write transaction */ + u8 isExclusive; /* True if pWriter has an EXCLUSIVE lock on the db */ + u8 isPending; /* If waiting for read-locks to clear */ #endif u8 *pTmpSpace; /* BtShared.pageSize bytes of space for tmp use */ }; @@ -415,6 +454,17 @@ struct CellInfo { }; /* +** Maximum depth of an SQLite B-Tree structure. Any B-Tree deeper than +** this will be declared corrupt. This value is calculated based on a +** maximum database size of 2^31 pages a minimum fanout of 2 for a +** root-node and 3 for all other internal nodes. +** +** If a tree that appears to be taller than this is encountered, it is +** assumed that the database is corrupt. +*/ +#define BTCURSOR_MAX_DEPTH 20 + +/* ** A cursor is a pointer to a particular entry within a particular ** b-tree within a database file. ** @@ -434,8 +484,7 @@ struct BtCursor { BtCursor *pNext, *pPrev; /* Forms a linked list of all cursors */ struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */ Pgno pgnoRoot; /* The root page of this tree */ - MemPage *pPage; /* Page that contains the entry */ - int idx; /* Index of the entry in pPage->aCell[] */ + sqlite3_int64 cachedRowid; /* Next rowid cache. 0 means not valid */ CellInfo info; /* A parse of the cell we are pointing at */ u8 wrFlag; /* True if writable */ u8 atLast; /* Cursor pointing to the last entry */ @@ -443,11 +492,14 @@ struct BtCursor { 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 skip; /* (skip<0) -> Prev() is a no-op. (skip>0) -> Next() is */ + 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 */ #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] */ }; /* @@ -480,36 +532,10 @@ struct BtCursor { #define CURSOR_REQUIRESEEK 2 #define CURSOR_FAULT 3 -/* The database page the PENDING_BYTE occupies. This page is never used. -** TODO: This macro is very similary to PAGER_MJ_PGNO() in pager.c. They -** should possibly be consolidated (presumably in pager.h). -** -** If disk I/O is omitted (meaning that the database is stored purely -** in memory) then there is no pending byte. -*/ -#ifdef SQLITE_OMIT_DISKIO -# define PENDING_BYTE_PAGE(pBt) 0x7fffffff -#else -# define PENDING_BYTE_PAGE(pBt) ((PENDING_BYTE/(pBt)->pageSize)+1) -#endif - -/* -** A linked list of the following structures is stored at BtShared.pLock. -** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor -** is opened on the table with root page BtShared.iTable. Locks are removed -** from this list when a transaction is committed or rolled back, or when -** a btree handle is closed. +/* +** The database page the PENDING_BYTE occupies. This page is never used. */ -struct BtLock { - Btree *pBtree; /* Btree handle holding this lock */ - Pgno iTable; /* Root page of table */ - u8 eLock; /* READ_LOCK or WRITE_LOCK */ - BtLock *pNext; /* Next in BtShared.pLock list */ -}; - -/* Candidate values for BtLock.eLock */ -#define READ_LOCK 1 -#define WRITE_LOCK 2 +# define PENDING_BYTE_PAGE(pBt) PAGER_MJ_PGNO(pBt) /* ** These macros define the location of the pointer-map entry for a @@ -597,7 +623,7 @@ typedef struct IntegrityCk IntegrityCk; struct IntegrityCk { BtShared *pBt; /* The tree being checked out */ Pager *pPager; /* The associated pager. Also accessible by pBt->pPager */ - int nPage; /* Number of pages in the database */ + Pgno nPage; /* Number of pages in the database */ int *anRef; /* Number of times each page is referenced */ int mxErr; /* Stop accumulating errors when this reaches zero */ int nErr; /* Number of messages written to zErrMsg so far */ @@ -609,19 +635,6 @@ struct IntegrityCk { ** Read or write a two- and four-byte big-endian integer values. */ #define get2byte(x) ((x)[0]<<8 | (x)[1]) -#define put2byte(p,v) ((p)[0] = (v)>>8, (p)[1] = (v)) +#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v)) #define get4byte sqlite3Get4byte #define put4byte sqlite3Put4byte - -/* -** Internal routines that should be accessed by the btree layer only. -*/ -int sqlite3BtreeGetPage(BtShared*, Pgno, MemPage**, int); -int sqlite3BtreeInitPage(MemPage *pPage, MemPage *pParent); -void sqlite3BtreeParseCellPtr(MemPage*, u8*, CellInfo*); -void sqlite3BtreeParseCell(MemPage*, int, CellInfo*); -int sqlite3BtreeRestoreCursorPosition(BtCursor *pCur); -void sqlite3BtreeGetTempCursor(BtCursor *pCur, BtCursor *pTempCur); -void sqlite3BtreeReleaseTempCursor(BtCursor *pCur); -int sqlite3BtreeIsRootPage(MemPage *pPage); -void sqlite3BtreeMoveToParent(BtCursor *pCur); |