DragonFly On-Line Manual Pages

Search: Section:  

MTBL_MERGE(1)                                                    MTBL_MERGE(1)


NAME

       mtbl_merge - merge MTBL data from multiple input files into a single
       output file


SYNOPSIS

       User-provided functions:

       typedef void *
       (*mtbl_merge_init_func)(void);

       typedef void
       (*mtbl_merge_free_func)(void *clos);

       typedef void
       (*mtbl_merge_func)(void *clos,
               const uint8_t *key, size_t len_key,
               const uint8_t *val0, size_t len_val0,
               const uint8_t *val1, size_t len_val1,
               uint8_t **merged_val, size_t *len_merged_val);

       Command line tool:

       export MTBL_MERGE_DSO="libexample.so.0"
       export MTBL_MERGE_FUNC_PREFIX="example_merge"
       mtbl_merge [-b SIZE] [-c COMPRESSION] INPUT [INPUT]... OUTPUT


DESCRIPTION

       mtbl_merge(1) is a command-line driver for the mtbl_merger(3)
       interface. The mtbl_merger(3) interface requires a user-provided merge
       function, which is loaded from a shared object whose filename is
       specified in the environment variable MTBL_MERGE_DSO.

       The user-provided merge function must have the same type as the
       mtbl_merge_func function type given above in the synopsis. The symbol
       name of the merge function to be loaded from the user-provided DSO will
       be constructed by appending "_func" to the string provided in the
       MTBL_MERGE_FUNC_PREFIX environment variable, which must be non-empty.

       Additionally, two optional functions may be provided: an "init"
       function whose symbol name is "_init" appended to the function prefix,
       and a "free" function whose symbol name is "_free" appended to the
       function prefix. If the "init" function exists, it will be called at
       the beginning, before any calls to the merge function, and the return
       value from the init function will be passed as the first argument to
       the merge function. If the "free" function exists, it will be called at
       the end, after any calls to the merge function, and its argument will
       be the return value of the "init" function.

       The environment variable MTBL_MERGE_BLOCK_SIZE may optionally be set in
       order to configure the MTBL block size (in bytes) of the output file.


OPTIONS

       -b SIZE
           The uncompressed data block size hint for the output file, in
           bytes. The default value if unspecified is 8192 bytes (8
           kilobytes).

       -c COMPRESSION
           The compression algorithm to use for data blocks in the output
           file. The default value if unspecified is zlib. See the
           mtbl_info(1) manpage for the list of possible compression
           algorithms.


SEE ALSO

       mtbl_info(1) mtbl_merger(3)

                                  07/21/2015                     MTBL_MERGE(1)

Search: Section: