Fluentdで発生するエラー（「failed to initialize connection」など）の解決について

Fluentd(td-agent2)を用いてApache（2.2.15）のログをPostgresql（9.6.0）に格納しようとしています。
一通り、設定が完了したのですが、fluentdで以下のエラーが発生しており、上手く動作しません。
お手数ですが、問題解決に向けてアドバイスを頂けないでしょうか。宜しくお願いします。

◆td-agent.logのログ

2017-03-09 14:58:44 +0900 [info]: following tail of /var/log/httpd/access_log
2017-03-09 03:07:01 +0900 [warn]: suppressed same stacktrace
2017-03-09 11:13:14 +0900 [warn]: retry count exceededs limit.
2017-03-09 11:13:14 +0900 [warn]: suppressed same stacktrace
2017-03-09 11:13:14 +0900 [error]: throwing away old logs.
2017-03-09 14:58:42 +0900 [info]: shutting down fluentd
2017-03-09 14:58:42 +0900 [info]: shutting down input type="tail" plugin_id="object:3f9a8b9abae0"
2017-03-09 14:58:42 +0900 [info]: shutting down output type="pgjson" plugin_id="object:3f9a8b5716f0"
2017-03-09 14:58:42 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/2.1.0/monitor.rb:211:in `mon_synchronize'

<source> tag apache.access port 5432 time_col time 2017-03-09 14:58:44 +0900 [info]: following tail of /var/log/httpd/access_log 2017-03-09 03:07:01 +0900 [warn]: suppressed same stacktrace 2017-03-09 11:13:14 +0900 [warn]: retry count exceededs limit. 2017-03-09 11:13:14 +0900 [warn]: suppressed same stacktrace 2017-03-09 11:13:14 +0900 [error]: throwing away old logs. 2017-03-09 14:58:42 +0900 [info]: shutting down fluentd 2017-03-09 14:58:42 +0900 [info]: shutting down input type="tail" plugin_id="object:3f9a8b9abae0" 2017-03-09 14:58:42 +0900 [info]: shutting down output type="pgjson" plugin_id="object:3f9a8b5716f0" 2017-03-09 14:58:42 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/2.1.0/monitor.rb:211:in `mon_synchronize' <source> tag apache.access port 5432 time_col time 2017-03-09 14:58:44 +0900 [info]: following tail of /var/log/httpd/access_log host localhost port 5432 time_col time 2017-03-09 14:58:44 +0900 [info]: following tail of /var/log/httpd/access_log <source> tag apache.access port 5432 time_col time 2017-03-09 14:58:44 +0900 [info]: following tail of /var/log/httpd/access_log 2017-03-09 14:58:44 +0900 [info]: gem 'fluentd' version '0.12.31' 2017-03-09 14:58:44 +0900 [info]: adding match pattern="apache.access" type="pgjson" 2017-03-09 14:58:44 +0900 [info]: adding source type="tail" 2017-03-09 14:58:44 +0900 [info]: using configuration file: <ROOT> <source> type tail format apache path /var/log/httpd/access_log pos_file /var/log/td-agent/pos/apache.test.log.pos tag apache.access </source> <match apache.access> type pgjson host localhost port 5432 database weblog table fluentd user postgres password xxxxxx time_col time tag_col tag record_col record </match> </ROOT> 2017-03-09 14:58:44 +0900 [info]: following tail of /var/log/httpd/access_log 2017-03-09 14:59:44 +0900 [warn]: temporarily failed to flush the buffer. next_retry=2017-03-09 14:59:45 +0900 error_class="RuntimeError" error="failed to initialize connection: FATAL: \xE3\x83\xA6\xE3\x83\xBC\xE3\x82\xB6\"postgres\"\xE3\x81\xAEIdent\xE8\xAA\x8D\xE8\xA8\xBC\xE3\x81\xAB\xE5\xA4\xB1\xE6\x95\x97\xE3\x81\x97\xE3\x81\xBE\xE3\x81\x97\xE3\x81\x9F\n" plugin_id="object:3fde721ebd34" 2017-03-09 14:59:44 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/gems/2.1.0/gems/fluent-plugin-pgjson-0.0.8/lib/fluent/plugin/out_pgjson.rb:71:in `rescue in init_connection' 2017-03-09 14:59:44 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/gems/2.1.0/gems/fluent-plugin-pgjson-0.0.8/lib/fluent/plugin/out_pgjson.rb:64:in `init_connection' 2017-03-09 14:59:44 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/gems/2.1.0/gems/fluent-plugin-pgjson-0.0.8/lib/fluent/plugin/out_pgjson.rb:41:in `write' 2017-03-09 14:59:44 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/gems/2.1.0/gems/fluentd-0.12.31/lib/fluent/buffer.rb:354:in `write_chunk' 2017-03-09 14:59:44 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/gems/2.1.0/gems/fluentd-0.12.31/lib/fluent/buffer.rb:333:in `pop' 2017-03-09 14:59:44 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/gems/2.1.0/gems/fluentd-0.12.31/lib/fluent/output.rb:342:in `try_flush' 2017-03-09 14:59:44 +0900 [warn]: /opt/td-agent/embedded/lib/ruby/gems/2.1.0/gems/fluentd-0.12.31/lib/fluent/output.rb:149:in `run' 2017-03-09 14:59:45 +0900 [warn]: temporarily failed to flush the buffer. next_retry=2017-03-09 14:59:47 +0900 error_class="RuntimeError" error="failed to initialize connection: FATAL: \xE3\x83\xA6\xE3\x83\xBC\xE3\x82\xB6\"postgres\"\xE3\x81\xAEIdent\xE8\xAA\x8D\xE8\xA8\xBC\xE3\x81\xAB\xE5\xA4\xB1\xE6\x95\x97\xE3\x81\x97\xE3\x81\xBE\xE3\x81\x97\xE3\x81\x9F\n" plugin_id="object:3fde721ebd34" 2017-03-09 14:59:45 +0900 [warn]: suppressed same stacktrace 2017-03-09 14:59:47 +0900 [warn]: temporarily failed to flush the buffer. next_retry=2017-03-09 14:59:50 +0900 error_class="RuntimeError" error="failed to initialize connection: FATAL: \xE3\x83\xA6\xE3\x83\xBC\xE3\x82\xB6\"postgres\"\xE3\x81\xAEIdent\xE8\xAA\x8D\xE8\xA8\xBC\xE3\x81\xAB\xE5\xA4\xB1\xE6\x95\x97\xE3\x81\x97\xE3\x81\xBE\xE3\x81\x97\xE3\x81\x9F\n" plugin_id="object:3fde721ebd34"

◆◆td-agentの設定

<source> type tail format apache path /var/log/httpd/access_log pos_file /var/log/td-agent/pos/apache.test.log.pos tag apache.access </source> <match apache.access> type pgjson host localhost port 5432 database weblog table fluentd user postgres password XXXXXXXX time_col time tag_col tag record_col record </match>