Improve docs with default parallelism settings.

Fix #442 by adding the default values of concurrency and workers.

Author: dimitri

pgloader.1

@@ -1,7 +1,7 @@
 .\" generated with Ronn/v0.7.3
 .\" http://github.com/rtomayko/ronn/tree/0.7.3
 .
-.TH "PGLOADER" "1" "August 2016" "ff" ""
+.TH "PGLOADER" "1" "December 2016" "ff" ""
 .
 .SH "NAME"
 \fBpgloader\fR \- PostgreSQL data loader
@@ -496,6 +496,9 @@ So with \fBworkers = 4, concurrency = 2\fR, the parallel scheduler will maintain
 With \fBworkers = 8, concurrency = 1\fR, we then are able to work on several units of work at the same time\. In the database sources, a unit of work is a table, so those settings allow pgloader to be active on as many as 3 tables at any time in the load process\.
 .
 .P
+The defaults are \fBworkers = 4, concurrency = 1\fR when loading from a database source, and \fBworkers = 8, concurrency = 2\fR when loading from something else (currently, a file)\. Those defaults are arbitrary and waiting for feedback from users, so please consider providing feedback if you play with the settings\.
+.
+.P
 As the \fBCREATE INDEX\fR threads started by pgloader are only waiting until PostgreSQL is done with the real work, those threads are \fINOT\fR counted into the concurrency levels as detailed here\.
 .
 .P

pgloader.1.md

@@ -445,6 +445,12 @@ units of work at the same time. In the database sources, a unit of work is a
 table, so those settings allow pgloader to be active on as many as 3 tables
 at any time in the load process.
 
+The defaults are `workers = 4, concurrency = 1` when loading from a database
+source, and `workers = 8, concurrency = 2` when loading from something else
+(currently, a file). Those defaults are arbitrary and waiting for feedback
+from users, so please consider providing feedback if you play with the
+settings.
+
 As the `CREATE INDEX` threads started by pgloader are only waiting until
 PostgreSQL is done with the real work, those threads are *NOT* counted into
 the concurrency levels as detailed here.