diff options
| -rw-r--r-- | src/backend/catalog/Catalog.pm | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/src/backend/catalog/Catalog.pm b/src/backend/catalog/Catalog.pm index eee7cb3b90e..2889cb9fb06 100644 --- a/src/backend/catalog/Catalog.pm +++ b/src/backend/catalog/Catalog.pm @@ -16,6 +16,9 @@ package Catalog; use strict; use warnings; +use File::Compare; + + # Parses a catalog header file into a data structure describing the schema # of the catalog. sub ParseHeader @@ -336,15 +339,29 @@ sub AddDefaultValues } # Rename temporary files to final names. -# Call this function with the final file name and the .tmp extension +# Call this function with the final file name and the .tmp extension. +# +# If the final file already exists and has identical contents, don't +# overwrite it; this behavior avoids unnecessary recompiles due to +# updating the mod date on unchanged header files. +# # Note: recommended extension is ".tmp$$", so that parallel make steps -# can't use the same temp files +# can't use the same temp files. sub RenameTempFile { my $final_name = shift; my $extension = shift; my $temp_name = $final_name . $extension; - rename($temp_name, $final_name) || die "rename: $temp_name: $!"; + + if (-f $final_name + && compare($temp_name, $final_name) == 0) + { + unlink $temp_name || die "unlink: $temp_name: $!"; + } + else + { + rename($temp_name, $final_name) || die "rename: $temp_name: $!"; + } } # Find a symbol defined in a particular header file and extract the value. |