if (!path.getFileSystem(conf).exists(pathSchema)) {
throw new IOException("BT Schema file doesn't exist: " + pathSchema);
}
// read schema file
FSDataInputStream in = path.getFileSystem(conf).open(pathSchema);
Version version = new Version(in);
// verify compatibility against SCHEMA_VERSION
if (!version.compatibleWith(SCHEMA_VERSION)) {
new IOException("Incompatible versions, expecting: " + SCHEMA_VERSION
+ "; found in file: " + version);
}
// read comparator