drh
b6f4148607
size determination. (CVS 1374) FossilOrigin-Name: f63fb6dd4e8e33d4c1983396b1a0305836ee4df7
106 lines
3.4 KiB
C
106 lines
3.4 KiB
C
/*
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** 2001 September 15
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** This header file defines the interface that the sqlite page cache
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** subsystem. The page cache subsystem reads and writes a file a page
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** at a time and provides a journal for rollback.
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**
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** @(#) $Id: pager.h,v 1.29 2004/05/14 01:58:13 drh Exp $
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*/
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/*
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** The size of a page.
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**
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** You can change this value to another (reasonable) value you want.
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** It need not be a power of two, though the interface to the disk
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** will likely be faster if it is.
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**
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** Experiments show that a page size of 1024 gives the best speed
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** for common usages. The speed differences for different sizes
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** such as 512, 2048, 4096, an so forth, is minimal. Note, however,
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** that changing the page size results in a completely imcompatible
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** file format.
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*/
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#ifndef SQLITE_PAGE_SIZE
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#define SQLITE_PAGE_SIZE 1024
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#endif
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/*
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** Number of extra bytes of data allocated at the end of each page and
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** stored on disk but not used by the higher level btree layer. Changing
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** this value results in a completely incompatible file format.
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*/
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#ifndef SQLITE_PAGE_RESERVE
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#define SQLITE_PAGE_RESERVE 0
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#endif
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/*
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** The total number of usable bytes stored on disk for each page.
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** The usable bytes come at the beginning of the page and the reserve
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** bytes come at the end.
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*/
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#define SQLITE_USABLE_SIZE (SQLITE_PAGE_SIZE-SQLITE_PAGE_RESERVE)
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/*
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** Maximum number of pages in one database.
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*/
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#define SQLITE_MAX_PAGE 1073741823
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/*
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** The type used to represent a page number. The first page in a file
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** is called page 1. 0 is used to represent "not a page".
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*/
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typedef unsigned int Pgno;
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/*
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** Each open file is managed by a separate instance of the "Pager" structure.
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*/
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typedef struct Pager Pager;
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/*
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** See source code comments for a detailed description of the following
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** routines:
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*/
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int sqlite3pager_open(Pager **ppPager, const char *zFilename,
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int nPage, int nExtra, int useJournal);
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void sqlite3pager_set_destructor(Pager*, void(*)(void*,int));
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void sqlite3pager_set_cachesize(Pager*, int);
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int sqlite3pager_close(Pager *pPager);
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int sqlite3pager_get(Pager *pPager, Pgno pgno, void **ppPage);
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void *sqlite3pager_lookup(Pager *pPager, Pgno pgno);
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int sqlite3pager_ref(void*);
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int sqlite3pager_unref(void*);
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Pgno sqlite3pager_pagenumber(void*);
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int sqlite3pager_write(void*);
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int sqlite3pager_iswriteable(void*);
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int sqlite3pager_overwrite(Pager *pPager, Pgno pgno, void*);
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int sqlite3pager_pagecount(Pager*);
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int sqlite3pager_truncate(Pager*,Pgno);
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int sqlite3pager_begin(void*);
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int sqlite3pager_commit(Pager*);
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int sqlite3pager_rollback(Pager*);
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int sqlite3pager_isreadonly(Pager*);
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int sqlite3pager_stmt_begin(Pager*);
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int sqlite3pager_stmt_commit(Pager*);
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int sqlite3pager_stmt_rollback(Pager*);
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void sqlite3pager_dont_rollback(void*);
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void sqlite3pager_dont_write(Pager*, Pgno);
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int *sqlite3pager_stats(Pager*);
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void sqlite3pager_set_safety_level(Pager*,int);
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const char *sqlite3pager_filename(Pager*);
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int sqlite3pager_rename(Pager*, const char *zNewName);
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void sqlite3pager_set_codec(Pager*,void(*)(void*,void*,Pgno,int),void*);
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#ifdef SQLITE_TEST
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void sqlite3pager_refdump(Pager*);
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int pager3_refinfo_enable;
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#endif
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