[sql] Log tag with sqlite errors.

sql/connection.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sql/connection.h"
 
 #include <string.h>
 
 #include "base/files/file_path.h"
 #include "base/file_util.h"
@@ skipping 1009 matching lines @@
           base::HistogramBase::kUmaTargetedHistogramFlag);
   if (histogram)
     histogram->Add(sample);
 }
 
 int Connection::OnSqliteError(int err, sql::Statement *stmt) {
   UMA_HISTOGRAM_SPARSE_SLOWLY("Sqlite.Error", err);
   AddTaggedHistogram("Sqlite.Error", err);
 
   // Always log the error.
-  LOG(ERROR) << "sqlite error " << err
+  LOG(ERROR) << histogram_tag_ << " sqlite error " << err

[Greg Spencer (Chromium), 2013/09/25 18:36:30]

Would it make sense to use sqlite3_column_database_name to get the database name
from the statement?

Otherwise, I agree with you that we don't want untagged ops.

[Scott Hess - ex-Googler, 2013/09/25 19:37:04]

http://www.sqlite.org/c3ref/column_database_name.html says they are only enabled
if compiled the right way.  Also, thinking on it, I bet there isn't even a
statement for these errors, it's probably failing even accessing the schema
info.

More achievable might be to add a line for sqlite3_sql() if stmt is non-NULL. 
That would not cover calls to Execute(), though... but it would probably be easy
to modify things to hit that case, too.  That should make it pretty easy to
backtrack to which caller is calling it, for all the good that will do.

OK, I'm going to tweak things a little more.

              << ", errno " << GetLastErrno()
              << ": " << GetErrorMessage();
 
   if (!error_callback_.is_null()) {
     // Fire from a copy of the callback in case of reentry into
     // re/set_error_callback().
     // TODO(shess): <http://crbug.com/254584>
     ErrorCallback(error_callback_).Run(err, stmt);
     return err;
   }
@@ skipping 33 matching lines @@
   }
 
   // Best effort to put things back as they were before.
   const char kNoWritableSchema[] = "PRAGMA writable_schema = OFF";
   ignore_result(Execute(kNoWritableSchema));
 
   return ret;
 }
 
 }  // namespace sql