mtbl_source(3) [debian man page]

MTBL_SOURCE(3)															    MTBL_SOURCE(3)

NAME

       mtbl_source - obtain key-value entries from a data source

SYNOPSIS

       #include <mtbl.h>

       struct mtbl_iter *
       mtbl_source_iter(const struct mtbl_source *s);

       struct mtbl_iter *
       mtbl_source_get(const struct mtbl_source *s, const uint8_t *key, size_t len_key);

       struct mtbl_iter *
       mtbl_source_get_prefix(
	       const struct mtbl_source *s,
	       const uint8_t *prefix, size_t len_prefix);

       struct mtbl_iter *
       mtbl_source_get_range(
	       const struct mtbl_source *s,
	       const uint8_t *key0, size_t len_key0,
	       const uint8_t *key1, size_t len_key1);

       mtbl_res
       mtbl_source_write(const struct mtbl_source *s, struct mtbl_writer *w);

       void
       mtbl_source_destroy(struct mtbl_source **s);

DESCRIPTION

       The mtbl_source iterface provides an abstraction for reading key-value entries from mtbl data sources.

       mtbl_source_iter() provides an iterator over all of the entries in the data source.

       mtbl_source_get() provides an exact match iterator which returns all entries whose key matches the key provided in the arguments key and
       len_key.

       mtbl_source_get_prefix() provides a prefix iterator which returns all entries whose keys start with prefix and are at least len_prefix
       bytes long.

       mtbl_source_get_range() provides a range iterator which returns all entries whose keys are between key0 and key1 inclusive.

       mtbl_source_write() is a convenience function for reading all of the entries from a source and writing them to an mtbl_writer object. It is
       equivalent to calling mtbl_writer_add() on all of the entries returned from mtbl_source_iter().

RETURN VALUE

       mtbl_source_iter(), mtbl_source_get(), mtbl_source_get_prefix(), and mtbl_source_get_range() return mtbl_iter objects.

       mtbl_source_write() returns mtbl_res_success if all of the entries in the data source were successfully written to the mtbl_writer
       argument, and mtbl_res_failure otherwise.

SEE ALSO

       mtbl_iter(3)

								    05/29/2012							    MTBL_SOURCE(3)

MTBL_WRITER(3)															    MTBL_WRITER(3)

NAME

       mtbl_writer - create an MTBL file

SYNOPSIS

       #include <mtbl.h>

       Writer objects:

       struct mtbl_writer *
       mtbl_writer_init(const char *fname, const struct mtbl_writer_options *wopt);

       struct mtbl_writer *
       mtbl_writer_init_fd(int fd, const struct mtbl_writer_options *wopt);

       void
       mtbl_writer_destroy(struct mtbl_writer **w);

       mtbl_res
       mtbl_writer_add(struct mtbl_writer *w,
	       const uint8_t *key, size_t len_key,
	       const uint8_t *val, size_t len_val);

       Writer options:

       struct mtbl_writer_options *
       mtbl_writer_options_init(void);

       void
       mtbl_writer_options_destroy(struct mtbl_writer_options **wopt);

       void
       mtbl_writer_options_set_compression(
	       struct mtbl_writer_options *wopt,
	       mtbl_compression_type compression_type);

       void
       mtbl_writer_options_set_block_size(
	       struct mtbl_writer_options *wopt,
	       size_t block_size);

       void
       mtbl_writer_options_set_block_restart_interval(
	       struct mtbl_writer_options *wopt,
	       size_t block_restart_interval);

DESCRIPTION

       MTBL files are written to disk by creating an mtbl_writer object, calling mtbl_writer_add() for each key-value entry, and then calling
       mtbl_writer_destroy().

       mtbl_writer_add() copies key-value pairs from the caller into the mtbl_writer object. Keys are specified as a pointer to a buffer, key, and
       the length of that buffer, len_key. Values are specified as a pointer to a buffer, val, and the length of that buffer, len_val.

       Keys must be in sorted, lexicographical byte order. The same key may not be added to an mtbl_writer more than once. If the input entries
       are not sorted or may contain duplicate keys, then the mtbl_sorter(3) interface should be used instead.

       mtbl_writer objects may be created by calling mtbl_writer_init() with an fname argument specifying a filename to be created. The filename
       must not already exist on the filesystem. Or, mtbl_writer_init_fd() may be called with an fd argument specifying an open, writable file
       descriptor. No data may have been written to the file descriptor.

       If the wopt parameter to mtbl_writer_init() or mtbl_writer_init_fd() is non-NULL, the parameters specified in the mtbl_writer_options
       object will be configured into the mtbl_writer object.

   Writer options
       compression
	   Specifies the compression algorithm to use on data blocks. Possible values are MTBL_COMPRESSION_NONE, MTBL_COMPRESSION_SNAPPY, or
	   MTBL_COMPRESSION_ZLIB (the default).

       block_size
	   The maximum size of uncompressed data blocks, specified in bytes. The default is 8 kilobytes.

       block_restart_interval
	   How frequently to restart intra-block key prefix compression. The default is every 16 keys.

RETURN VALUE

       mtbl_writer_init() and mtbl_writer_init_fd() return NULL on failure, and non-NULL on success.

       mtbl_writer_add() returns mtbl_res_success if the key-value entry was successfully copied into the mtbl_writer object, and mtbl_res_failure
       if not, for instance if there has been a key-ordering violation.

								    05/29/2012							    MTBL_WRITER(3)