Write messages directly onto message buffer instead of allocating on own buffer

[zainkabani]

pgbench -t 1000 -c 16 -j 2 --protocol extended -C:

PR:

Stats {
    allocations: 3873384,
    deallocations: 3870448,
    reallocations: 130708,
    bytes_allocated: 497650190,
    bytes_deallocated: 496466494,
    bytes_reallocated: 3722992,
}

Original:

Stats {
    allocations: 4578799,
    deallocations: 4575881,
    reallocations: 130689,
    bytes_allocated: 509003135,
    bytes_deallocated: 507846373,
    bytes_reallocated: 3716031,
}

Results in about a 15% decrease in allocations

pgbench -t 1000 -c 16 -j 2 --protocol extended:

PR

Stats {
    allocations: 2656700,
    deallocations: 2653782,
    reallocations: 2808,
    bytes_allocated: 65691251,
    bytes_deallocated: 64544049,
    bytes_reallocated: 742898,
}

Original

STATS: Stats {
    allocations: 3361868,
    deallocations: 3358897,
    reallocations: 2863,
    bytes_allocated: 77151598,
    bytes_deallocated: 75935794,
    bytes_reallocated: 757720,
}

Results in about a 20% decrease in allocations

[levkk]

This is very neat!