pgsql: Doc: document possible need to raise kernel's somaxconn limit.

Doc: document possible need to raise kernel's somaxconn limit.

On fast machines, it's possible for applications such as pgbench
to issue connection requests so quickly that the postmaster's
listen queue overflows in the kernel, resulting in unexpected
failures (with not-very-helpful error messages).  Most modern OSes
allow the queue size to be increased, so document how to do that.

Per report from Kevin McKibbin.

Discussion: https://postgr.es/m/CADc_NKg2d+oZY9mg4DdQdoUcGzN2kOYXBu-3--RW_hEe0tUV=g@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/ba94dfd4c4f63cf8663f16e427bcc6fac35a4428

Modified Files
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doc/src/sgml/runtime.sgml | 16 ++++++++++++++++
1 file changed, 16 insertions(+)