hamsterdb Hinting Flags for Find, Insert,
[hamsterdb Database Configuration]

Defines

#define HAM_HINT_APPEND   0x00080000
#define HAM_HINT_PREPEND   0x00100000
#define HAM_HINTS_MASK   0x00FF0000

Detailed Description

Move and Erase

These flags can be bitwise-OR mixed with the flags as used with any of ham_cursor_insert, ham_insert, ham_cursor_erase, ham_erase, ham_find, ham_cursor_find, ham_cursor_find_ex and ham_cursor_move.

These flags override the Database/Environment wide DAM (Data Access Mode) preferences as set by ham_env_create or ham_create. When these flags are not specified, performance hinting will be based on those DAM preferences (see hamsterdb Data Access Mode Codes).

See also:
hamsterdb Data Access Mode Codes

Define Documentation

#define HAM_HINT_APPEND   0x00080000

Flag for ham_cursor_insert

Mutually exclusive with flag HAM_HINT_PREPEND.

Hints the hamsterdb engine that the current key will compare as larger than any key already existing in the Database. The hamsterdb engine will verify this postulation and when found not to be true, will revert to a regular insert operation as if this flag was not specified. The incurred cost then is only one additional key comparison.

Definition at line 2012 of file hamsterdb.h.

#define HAM_HINT_PREPEND   0x00100000

Flag for ham_cursor_insert

Mutually exclusive with flag HAM_HINT_APPEND.

Hints the hamsterdb engine that the current key will compare as smaller than any key already existing in the Database. The hamsterdb engine will verify this postulation and when found not to be true, will revert to a regular insert operation as if this flag was not specified. The incurred cost then is only one additional key comparison.

Definition at line 2026 of file hamsterdb.h.

#define HAM_HINTS_MASK   0x00FF0000

Flag mask to extract the common hint flags from a find/move/insert/erase flag value.

Definition at line 2032 of file hamsterdb.h.


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