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mdbx: MAX_PAGESIZE always 64K.

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This commit is contained in:
Leo Yuriev
2017-05-31 17:10:17 +03:00
parent 19dd181b6f
commit 95ebdb7065
2 changed files with 52 additions and 52 deletions
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59
src/bits.h
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@@ -82,24 +82,6 @@
/*----------------------------------------------------------------------------*/
/* Basic constants and types */
/* The maximum size of a database page.
*
* It is 32k or 64k, since value-PAGEBASE must fit in
* MDBX_page.mp_upper.
*
* MDBX will use database pages < OS pages if needed.
* That causes more I/O in write transactions: The OS must
* know (read) the whole page before writing a partial page.
*
* Note that we don't currently support Huge pages. On Linux,
* regular data files cannot use Huge pages, and in general
* Huge pages aren't actually pageable. We rely on the OS
* demand-pager to read our data and page it out when memory
* 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
* maximum size of a data item. Data items larger than this size will
@@ -151,13 +133,6 @@ typedef uint64_t txnid_t;
* this is plenty. */
typedef uint16_t indx_t;
#define MIN_MAPSIZE (MIN_PAGESIZE * MIN_PAGENO)
#define MAX_MAPSIZE \
((sizeof(size_t) < 8) \
? UINT32_C(0x7ff80000) \
: ((sizeof(pgno_t) > 4) ? UINT64_C(0x7fffFFFFfff80000) \
: MAX_PAGENO * (uint64_t)MAX_PAGESIZE))
/*----------------------------------------------------------------------------*/
/* Core structures for database and shared memory (i.e. format definition) */
#pragma pack(push, 1)
@@ -308,9 +283,10 @@ typedef struct MDBX_meta {
* in the snapshot: Either used by a database or listed in a freeDB record. */
typedef struct MDBX_page {
union {
struct MDBX_page *mp_next; /* for in-memory list of freed pages,
* must be first field, see NEXT_LOOSE_PAGE */
uint64_t mp_validator; /* checksum of page content or a txnid during
* which the page has been updated */
struct MDBX_page *mp_next; /* for in-memory list of freed pages */
};
uint16_t mp_leaf2_ksize; /* key size if this is a LEAF2 page */
#define P_BRANCH 0x01 /* branch page */
@@ -343,6 +319,30 @@ typedef struct MDBX_page {
/* Size of the page header, excluding dynamic data at the end */
#define PAGEHDRSZ ((unsigned)offsetof(MDBX_page, mp_data))
/* The maximum size of a database page.
*
* It is 64K, but value-PAGEHDRSZ must fit in MDBX_page.mp_upper.
*
* MDBX will use database pages < OS pages if needed.
* That causes more I/O in write transactions: The OS must
* know (read) the whole page before writing a partial page.
*
* Note that we don't currently support Huge pages. On Linux,
* regular data files cannot use Huge pages, and in general
* Huge pages aren't actually pageable. We rely on the OS
* demand-pager to read our data and page it out when memory
* pressure from other processes is high. So until OSs have
* actual paging support for Huge pages, they're not viable. */
#define MAX_PAGESIZE 0x10000u
#define MIN_PAGESIZE 512u
#define MIN_MAPSIZE (MIN_PAGESIZE * MIN_PAGENO)
#define MAX_MAPSIZE \
((sizeof(size_t) < 8) \
? UINT32_C(0x7ff80000) \
: ((sizeof(pgno_t) > 4) ? UINT64_C(0x7fffFFFFfff80000) \
: MAX_PAGENO * (uint64_t)MAX_PAGESIZE))
#pragma pack(pop)
/* The header for the reader table (a memory-mapped lock file). */
@@ -885,11 +885,8 @@ static __inline size_t roundup2(size_t value, size_t granularity) {
/* Address of first usable data byte in a page, after the header */
#define PAGEDATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
/* ITS#7713, change PAGEBASE to handle 65536 byte pages */
#define PAGEBASE ((MDBX_DEVEL) ? PAGEHDRSZ : 0)
/* Number of nodes on a page */
#define NUMKEYS(p) (((p)->mp_lower - (PAGEHDRSZ - PAGEBASE)) >> 1)
#define NUMKEYS(p) ((p)->mp_lower >> 1)
/* The amount of space remaining in the page */
#define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower)
@@ -986,7 +983,7 @@ typedef struct MDBX_node {
/* Address of node i in page p */
static __inline MDBX_node *NODEPTR(MDBX_page *p, unsigned i) {
assert(NUMKEYS(p) > (unsigned)(i));
return (MDBX_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEBASE);
return (MDBX_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEHDRSZ);
}
/* Address of the key for the node */