Re: Add parallelism and glibc dependent only options to reindexdb

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Hi

I did some review and have few notes about behavior.

reindex database does not work with concurrently option:

> ./inst/bin/reindexdb --echo -d postgres -j 8 --concurrently
> SELECT pg_catalog.set_config('search_path', '', false);
> REINDEX SYSTEM CONCURRENTLY postgres;
> reindexdb: error: reindexing of system catalogs on database "postgres" failed: ERROR: cannot reindex system catalogs concurrently

I think we need print message and skip system catalogs for concurrently reindex.
Or we can disallow concurrently database reindex with multiple jobs. I prefer first option.

> + reindex_one_database(dbname, REINDEX_SCHEMA, &schemas, host,
> + port, username, prompt_password, progname,
> + echo, verbose, concurrently,
> + Min(concurrentCons, nsp_count));

Should be just concurrentCons instead of Min(concurrentCons, nsp_count)
reindex_one_database for REINDEX_SCHEMA will build tables list and then processing by available workers. So:
-j 8 -S public -S public -S public -S poblic -S public -S public - will work with 6 jobs (and without multiple processing for same table)
-j 8 -S public - will have only one worker regardless tables count

> if (concurrentCons > FD_SETSIZE - 1)

"if (concurrentCons >= FD_SETSIZE)" would not cleaner? Well, pgbench uses >= condition, vacuumdb uses > FD_SETSIZE - 1. No more FD_SETSIZE in conditions =)

regards, Sergei