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

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.

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

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

       -cCOMPRESSION
           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.

       -lLEVEL
           The numeric compression level passed to the compression algorithm. The default value and valid range
           depend on the chosen compression algorithm.

mtbl_info(1), mtbl_merger(3)

                                                   10/21/2021                                      MTBL_MERGE(1)

       User-provided functions:

       typedefvoid*(*mtbl_merge_init_func)(void);typedefvoid(*mtbl_merge_free_func)(void*clos);typedefvoid(*mtbl_merge_func)(void*clos,constuint8_t*key,size_tlen_key,constuint8_t*val0,size_tlen_val0,constuint8_t*val1,size_tlen_val1,uint8_t**merged_val,size_t*len_merged_val);

       Command line tool:

       exportMTBL_MERGE_DSO="libexample.so.0"exportMTBL_MERGE_FUNC_PREFIX="example_merge"mtbl_merge [-bSIZE] [-cCOMPRESSION] [-lLEVEL] INPUT [INPUT]... OUTPUT