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Convert to extension and add timestamp parsing function
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‎Makefile

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EXTENSION = pgulid
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DATA = pgulid--1.0.sql
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PGFILEDESC = "pgULID - An ULID generation extension for PostgreSQL"
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PG_CONFIG = pg_config
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PGXS := $(shell $(PG_CONFIG) --pgxs)
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include $(PGXS)

‎README.md

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@@ -27,6 +27,7 @@ A ULID however:
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```sql
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SELECT generate_ulid(); -- Output: 01D45VGTV648329YZFE7HYVGWC
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SELECT parse_ulid_timestamp('01D45VGTV648329YZFE7HYVGWC'); -- Output: 2019-02-20 16:23:49.35+00
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```
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## Specification
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### Components
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**Timestamp**
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- 48 bits
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- UNIX-time in milliseconds
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- Won't run out of space till the year 10895 AD
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**Entropy**
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- 80 bits
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- Timestamp
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- 48 bits
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- UNIX-time in milliseconds
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- Won't run out of space till the year 10895 AD
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- Entropy
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- 80 bits
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### String Representation
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```
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```text
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01AN4Z07BY 79KA1307SR9X4MV3
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|----------| |----------------|
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Timestamp Entropy

‎pgulid--1.0.sql

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-- complain if script is sourced in psql, rather than via CREATE EXTENSION
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\echo Use "CREATE EXTENSION pgulid" to load this file.\quit
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-- pgulid is based on OK Log's Go implementation of the ULID spec
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--
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-- https://github.com/oklog/ulid
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-- https://github.com/ulid/spec
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--
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-- Copyright 2016 The Oklog Authors
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-- Licensed under the Apache License, Version 2.0 (the "License");
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-- you may not use this file except in compliance with the License.
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-- You may obtain a copy of the License at
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--
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-- http://www.apache.org/licenses/LICENSE-2.0
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--
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-- Unless required by applicable law or agreed to in writing, software
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-- distributed under the License is distributed on an "AS IS" BASIS,
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-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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-- See the License for the specific language governing permissions and
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-- limitations under the License.
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CREATE OR REPLACE FUNCTION generate_ulid()
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RETURNS TEXT
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AS $$
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DECLARE
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-- Crockford's Base32
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encoding BYTEA = '0123456789ABCDEFGHJKMNPQRSTVWXYZ';
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timestamp BYTEA = E'\\000\\000\\000\\000\\000\\000';
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unix_time BIGINT;
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ulid BYTEA;
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BEGIN
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-- 6 timestamp bytes
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unix_time = (EXTRACT(EPOCH FROM NOW()) * 1000)::BIGINT;
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timestamp = SET_BYTE(timestamp, 0, (unix_time >> 40)::BIT(8)::INTEGER);
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timestamp = SET_BYTE(timestamp, 1, (unix_time >> 32)::BIT(8)::INTEGER);
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timestamp = SET_BYTE(timestamp, 2, (unix_time >> 24)::BIT(8)::INTEGER);
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timestamp = SET_BYTE(timestamp, 3, (unix_time >> 16)::BIT(8)::INTEGER);
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timestamp = SET_BYTE(timestamp, 4, (unix_time >> 8)::BIT(8)::INTEGER);
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timestamp = SET_BYTE(timestamp, 5, unix_time::BIT(8)::INTEGER);
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-- 10 entropy bytes
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ulid = timestamp || gen_random_bytes(10);
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-- Encode the timestamp
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RETURN CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 0) & 224) >> 5))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 0) & 31)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 1) & 248) >> 3))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 1) & 7) << 2) | ((GET_BYTE(ulid, 2) & 192) >> 6)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 2) & 62) >> 1))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 2) & 1) << 4) | ((GET_BYTE(ulid, 3) & 240) >> 4)))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 3) & 15) << 1) | ((GET_BYTE(ulid, 4) & 128) >> 7)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 4) & 124) >> 2))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 4) & 3) << 3) | ((GET_BYTE(ulid, 5) & 224) >> 5)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 5) & 31)))
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-- Encode the entropy
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 6) & 248) >> 3))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 6) & 7) << 2) | ((GET_BYTE(ulid, 7) & 192) >> 6)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 7) & 62) >> 1))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 7) & 1) << 4) | ((GET_BYTE(ulid, 8) & 240) >> 4)))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 8) & 15) << 1) | ((GET_BYTE(ulid, 9) & 128) >> 7)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 9) & 124) >> 2))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 9) & 3) << 3) | ((GET_BYTE(ulid, 10) & 224) >> 5)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 10) & 31)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 11) & 248) >> 3))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 11) & 7) << 2) | ((GET_BYTE(ulid, 12) & 192) >> 6)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 12) & 62) >> 1))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 12) & 1) << 4) | ((GET_BYTE(ulid, 13) & 240) >> 4)))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 13) & 15) << 1) | ((GET_BYTE(ulid, 14) & 128) >> 7)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 14) & 124) >> 2))
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|| CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 14) & 3) << 3) | ((GET_BYTE(ulid, 15) & 224) >> 5)))
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|| CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 15) & 31)));
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END
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$$
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LANGUAGE plpgsql
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VOLATILE;
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CREATE OR REPLACE FUNCTION parse_ulid_timestamp(ulid TEXT) RETURNS TIMESTAMP
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AS $$
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DECLARE
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-- Crockford's Base32
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-- Drop the 0 because strpos() returns 0 for not-found
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-- We've pre-validated already, so this is safe
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encoding TEXT = '123456789ABCDEFGHJKMNPQRSTVWXYZ';
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ts BIGINT;
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v CHAR[];
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BEGIN
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IF ulid IS NULL THEN
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RETURN null;
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END IF;
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ulid = upper(ulid);
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IF NOT ulid ~ '^[0123456789ABCDEFGHJKMNPQRSTVWXYZ]{26}$' THEN
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RAISE EXCEPTION 'Invalid ULID: %', ulid;
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END IF;
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-- first 10 ULID characters are the timestamp
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v = regexp_split_to_array(substring(ulid for 10), '');
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-- base32 is 5 bits / character
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-- posix milliseconds (6 bytes)
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ts = (strpos(encoding, v[1])::bigint << 45)
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+ (strpos(encoding, v[2])::bigint << 40)
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+ (strpos(encoding, v[3])::bigint << 35)
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+ (strpos(encoding, v[4])::bigint << 30)
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+ (strpos(encoding, v[5]) << 25)
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+ (strpos(encoding, v[6]) << 20)
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+ (strpos(encoding, v[7]) << 15)
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+ (strpos(encoding, v[8]) << 10)
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+ (strpos(encoding, v[9]) << 5)
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+ strpos(encoding, v[10]);
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RETURN to_timestamp(ts / 1000.0);
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END
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$$
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LANGUAGE plpgsql
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IMMUTABLE;

‎pgulid.control

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# pgulid extension
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comment = 'provides ULID generation and parsing'
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default_version = '1.0'
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relocatable = true
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requires = pgcrypto

‎pgulid.sql

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