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mdbx: trinity of meta-pages.

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This commit is contained in:
Leo Yuriev
2017-05-24 21:43:29 +03:00
parent 141306644d
commit 9eeb00f448
8 changed files with 537 additions and 346 deletions
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53
src/bits.h
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@@ -95,6 +95,7 @@
* pressure from other processes is high. So until OSs have
* actual paging support for Huge pages, they're not viable. */
#define MAX_PAGESIZE (PAGEBASE ? 0x10000 : 0x8000)
#define MIN_PAGESIZE 1024
/* The minimum number of keys required in a database page.
* Setting this to a larger value will place a smaller bound on the
@@ -127,14 +128,14 @@
#define CORE_DBS 2
/* Number of meta pages - also hardcoded elsewhere */
#define NUM_METAS 2
#define NUM_METAS 3
/* A page number in the database.
*
* MDBX uses 32 bit for page numbers. This limits database
* size up to 2^44 bytes, in case of 4K pages. */
typedef uint32_t pgno_t;
#define PRIaPGNO PRIu32
typedef uint64_t pgno_t;
#define PRIaPGNO PRIu64 /* TODO */
/* A transaction ID. */
typedef uint64_t txnid_t;
@@ -253,18 +254,12 @@ typedef struct MDBX_meta {
#define MDBX_DATASIGN_WEAK 1u
volatile uint64_t mm_datasync_sign;
#define MDBX_TEMPORARY_CRUTCH FIXME
#ifndef MDBX_TEMPORARY_CRUTCH
#define SIGN_IS_WEAK(sign) ((sign) == MDBX_DATASIGN_WEAK)
#define SIGN_IS_STEADY(sign) ((sign) > MDBX_DATASIGN_WEAK)
#else
#define SIGN_IS_WEAK(sign) (false && (sign) == MDBX_DATASIGN_WEAK)
#define SIGN_IS_STEADY(sign) (true || (sign) > MDBX_DATASIGN_WEAK)
#endif /* FIXME: MDBX_TEMPORARY_CRUTCH */
#define META_IS_WEAK(meta) SIGN_IS_WEAK((meta)->mm_datasync_sign)
#define META_IS_STEADY(meta) SIGN_IS_STEADY((meta)->mm_datasync_sign)
volatile mdbx_canary mm_canary;
mdbx_canary mm_canary;
} MDBX_meta;
/* Common header for all page types. The page type depends on mp_flags.
@@ -307,23 +302,17 @@ typedef struct MDBX_page {
};
uint32_t mp_pages; /* number of overflow pages */
};
indx_t mp_ptrs[1]; /* dynamic size */
/* dynamic size */
union {
indx_t mp_ptrs[1];
MDBX_meta mp_meta;
uint8_t mp_data[1];
};
} MDBX_page;
/* Size of the page header, excluding dynamic data at the end */
#define PAGEHDRSZ ((unsigned)offsetof(MDBX_page, mp_ptrs))
/* Buffer for a stack-allocated meta page.
* The members define size and alignment, and silence type
* aliasing warnings. They are not used directly; that could
* mean incorrectly using several union members in parallel. */
typedef union MDBX_metabuf {
MDBX_page mb_page;
struct {
char mm_pad[PAGEHDRSZ];
MDBX_meta mm_meta;
} mb_metabuf;
} MDBX_metabuf;
#define PAGEHDRSZ ((unsigned)offsetof(MDBX_page, mp_data))
/* The header for the reader table (a memory-mapped lock file). */
typedef struct MDBX_lockinfo {
@@ -795,22 +784,6 @@ static __inline void mdbx_jitter4testing(bool tiny) {
/* Internal prototypes and inlines */
int mdbx_reader_check0(MDBX_env *env, int rlocked, int *dead);
#define METAPAGE_1(env) (&((MDBX_metabuf *)(env)->me_map)->mb_metabuf.mm_meta)
#define METAPAGE_2(env) \
(&((MDBX_metabuf *)((env)->me_map + env->me_psize))->mb_metabuf.mm_meta)
static __inline MDBX_meta *mdbx_meta_head(MDBX_env *env) {
mdbx_jitter4testing(true);
MDBX_meta *a = METAPAGE_1(env);
mdbx_jitter4testing(true);
MDBX_meta *b = METAPAGE_2(env);
mdbx_jitter4testing(true);
return (a->mm_txnid > b->mm_txnid) ? a : b;
}
void mdbx_rthc_dtor(void *rthc);
void mdbx_rthc_lock(void);
void mdbx_rthc_unlock(void);