BUG: fix C parser thread safety. verify gil release close #2608

Author: wesm

RELEASE.rst

@@ -68,6 +68,7 @@ pandas 0.10.1
 
 **Bug fixes**
 
+  - Fix read_csv/read_table multithreading issues (GH2608_)
   - ``HDFStore``
 
     - correctly handle ``nan`` elements in string columns; serialize via the
@@ -127,6 +128,7 @@ pandas 0.10.1
 .. _GH2599: https://github.com/pydata/pandas/issues/2599
 .. _GH2604: https://github.com/pydata/pandas/issues/2604
 .. _GH2576: https://github.com/pydata/pandas/issues/2576
+.. _GH2608: https://github.com/pydata/pandas/issues/2608
 .. _GH2613: https://github.com/pydata/pandas/issues/2613
 .. _GH2616: https://github.com/pydata/pandas/issues/2616
 .. _GH2621: https://github.com/pydata/pandas/issues/2621

pandas/src/parser.pyx

@@ -172,8 +172,8 @@ cdef extern from "parser/tokenizer.h":
 
     void debug_print_parser(parser_t *self)
 
-    int tokenize_all_rows(parser_t *self) nogil
-    int tokenize_nrows(parser_t *self, size_t nrows) nogil
+    int tokenize_all_rows(parser_t *self)
+    int tokenize_nrows(parser_t *self, size_t nrows)
 
     int64_t str_to_int64(char *p_item, int64_t int_min,
                          int64_t int_max, int *error, char tsep)
@@ -695,8 +695,7 @@ cdef class TextReader:
 
     cdef _tokenize_rows(self, size_t nrows):
         cdef int status
-        with nogil:
-            status = tokenize_nrows(self.parser, nrows)
+        status = tokenize_nrows(self.parser, nrows)
 
         if self.parser.warn_msg != NULL:
             print >> sys.stderr, self.parser.warn_msg
@@ -723,8 +722,7 @@ cdef class TextReader:
                 raise ValueError('skip_footer can only be used to read '
                                  'the whole file')
         else:
-            with nogil:
-                status = tokenize_all_rows(self.parser)
+            status = tokenize_all_rows(self.parser)
 
             if self.parser.warn_msg != NULL:
                 print >> sys.stderr, self.parser.warn_msg