logstash向es里面导入mysql数据，表字段名称自动变成了小写

感谢各位的热心帮助，找到了问题的原因，我是使用logstash同步mysql数据的，因为在jdbc.conf里面没有添加 lowercase_column_names => "false"  这个属性，所以logstash默认把查询结果的列明改为了小写，同步进了es，所以就导致es里面看到的字段名称全是小写。
最后总结：es是支持大写字段名称的，问题出在logstash没用好，需要在同步配置中加上 lowercase_column_names => "false"  。记录下来希望可以帮到更多人，哈哈。

es中索引名称不支持大写，包含#，以_开头。具体查看MetaDataCreateIndexService类的validateIndexName方法

public void validateIndexName(String index, ClusterState state) {

        if (state.routingTable().hasIndex(index)) {

            throw new IndexAlreadyExistsException(new Index(index));

        }

        if (state.metaData().hasIndex(index)) {

            throw new IndexAlreadyExistsException(new Index(index));

        }

        if (!Strings.validFileName(index)) {

            throw new InvalidIndexNameException(new Index(index), index, "must not contain the following characters " + Strings.INVALID_FILENAME_CHARS);

        }

        if (index.contains("#")) {

            throw new InvalidIndexNameException(new Index(index), index, "must not contain '#'");

        }

        if (index.charAt(0) == '_') {

            throw new InvalidIndexNameException(new Index(index), index, "must not start with '_'");

        }

        if (!index.toLowerCase(Locale.ROOT).equals(index)) {

            throw new InvalidIndexNameException(new Index(index), index, "must be lowercase");

        }

        int byteCount = 0;

        try {

            byteCount = index.getBytes("UTF-8").length;

        } catch (UnsupportedEncodingException e) {

            // UTF-8 should always be supported, but rethrow this if it is not for some reason

            throw new ElasticsearchException("Unable to determine length of index name", e);

        }

        if (byteCount > MAX_INDEX_NAME_BYTES) {

            throw new InvalidIndexNameException(new Index(index), index,

                    "index name is too long, (" + byteCount +

                    " > " + MAX_INDEX_NAME_BYTES + ")");

        }

        if (state.metaData().hasAlias(index)) {

            throw new InvalidIndexNameException(new Index(index), index, "already exists as alias");

        }

        if (index.equals(".") || index.equals("..")) {

            throw new InvalidIndexNameException(new Index(index), index, "must not be '.' or '..'");

        }

    }

我印象中不支持大写。你插入个大写看报错不？

索引名称不支持大写，字段属性可以