ld.so: object '/usr/local/lib/libjemalloc.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS64): ignored.

This error message indicates that the dynamic linker (ld.so) was unable to preload the library '/usr/local/lib/libjemalloc.so' specified in the LD_PRELOAD environment variable, because the library is of the wrong ELF class.

The ELF (Executable and Linkable Format) is a common format for executable and object files in Unix-like operating systems. The ELF class specifies whether the binary is 32-bit (ELFCLASS32) or 64-bit (ELFCLASS64).

In this case, it seems that the library specified in LD_PRELOAD is a 64-bit library, but the program being executed is a 32-bit binary or vice versa. This mismatch between the ELF class of the library and the program can cause the dynamic linker to ignore the library and fail to preload it.

To resolve this issue, you can try to use a library with the correct ELF class that matches the program. Alternatively, you can try to run the program on an operating system or architecture that supports the library's ELF class.