Improve guessing of CSV parameters.

In this commit we fail the guess faster, allowing to test for a much larger
sample. The sample is still hard-coded, but this time to 1000 lines.

Also add a test case, see #618.

src/sources/csv/csv-guess.lisp

@@ -49,11 +49,11 @@
                                          :separator separator
                                          :escape escape)
                       ((or cl-csv:csv-parse-error type-error) ()
-                        nil)))))
+                        (return-from try-csv-params nil))))))
     (and rows
 	 (every (lambda (row) (= cols (length row))) rows))))
 
-(defun guess-csv-params (filename-or-stream nb-cols &key (sample-size 10))
+(defun guess-csv-params (filename-or-stream nb-cols &key (sample-size 1000))
   "Try a bunch of field separators with LINES and return the first one that
    returns COLS number of columns"
   (let ((sample

test/Makefile

@@ -11,6 +11,7 @@ REGRESS= allcols.load 		    \
          csv-error.load 	    \
          csv-escape-mode.load 	    \
          csv-filename-pattern.load  \
+         csv-guess.load             \
          csv-header.load            \
          csv-json.load              \
          csv-keep-extra-blanks.load \

test/csv-guess.load

@@ -0,0 +1,21 @@
+LOAD CSV
+     FROM data/track.csv
+     INTO postgresql:///pgloader?csv.track
+
+     WITH truncate
+
+   BEFORE LOAD DO
+    $$ create schema if not exists csv; $$,
+    $$ drop table if exists csv.track; $$,
+    $$ create table csv.track (
+          trackid      bigserial primary key,
+          track        text,
+          album        text,
+          media        text,
+          genre        text,
+          composer     text,
+          milliseconds bigint,
+          bytes        bigint,
+          unitprice    numeric
+       );
+    $$;