Noboru Saito noborus

TEMPORARY TABLE（一時テーブル）を探る

PostgreSQLのTEMPORARY TABLE(一時テーブル)について主に速度面について探っていきます。ここで書かれていることはPostgreSQL 10を対象としています。

はじめに

PostgreSQLのTEMPORARY TABLE(一時テーブル)は接続したセッションの間にしか生存できないテーブルです。このテーブルは他のセッションからはアクセスすることができません。

	package main

	import (
	"database/sql"
	"fmt"

	_ "github.com/go-sql-driver/mysql"
	)

	func main() {

	SELECT e.euc,convert(e.euc,'EUC_JIS_2004','UTF-8') as utf8, convert_from(convert(e.euc,'EUC_JIS_2004','UTF-8'),'UTF-8') as chr FROM (SELECT decode('8f'\|\|to_hex('xa1a1'::bit(16)::int+generate_series(0,93)),'hex') as euc ) as e;


	euc \| utf8 \| chr
	----------+------------+-----
	\x8fa1a1 \| \xf0a08289 \| 𠂉
	\x8fa1a2 \| \xe4b882 \| 丂
	\x8fa1a3 \| \xe4b88f \| 丏
	\x8fa1a4 \| \xe4b892 \| 丒
	\x8fa1a5 \| \xe4b8a9 \| 丩

	SELECT '0x' \|\|
	encode(substr(s.word::text,generate_series(1,length(s.word::text),1),1)::bytea, 'hex') AS code,
	substr(s.word::text,generate_series(1,length(s.word::text),1),1) AS char
	FROM
	(SELECT '漢字' AS word) AS s;

	code \| char
	----------+------
	0xe6bca2 \| 漢
	0xe5ad97 \| 字

	SELECT COUNT (char) AS frequency, char
	FROM
	(SELECT substr (column_name, generate_series (1, LENGTH (column_name)), 1) AS char
	FROM table_name) AS d
	GROUP BY char
	ORDER BY frequency DESC;

	// Use Gists to store code you would like to remember later on
	console.log(window); // log the "window" object to the console

	#! /usr/bin/ruby
	# -- coding: utf-8 --

	require 'dbus'

	INPUT_TEXT="akemasiteomedetougozaimasu"

	IBUS_SERVICE="org.freedesktop.IBus"
	IBUS_PATH_IBUS="/org/freedesktop/IBus"
	IBUS_INTERFACE_IBUS="org.freedesktop.IBus"

	# Features of ov

	Column selection is possible in wrap mode.