1.
大解密！用 PostgreSQL 提升 350 倍的
Funliday 推薦景點計算速度
Kewang

2.
Kewang
● 王慕羣 Kewang
● Java / JavaScript
● HBase / PostgreSQL / MongoDB / ElasticSearch
● Git / DevOps
●
熱愛開源
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FacebookFacebook Kewang 的資訊進化論Kewang 的資訊進化論
devopsday taipeidevopsday taipei '17'17
hadoopconhadoopcon '14 '15'14 '15
jcconfjcconf '16 '17 '18'16 '17 '18
modernwebmodernweb '18 '19 '20'18 '19 '20
GitHubGitHub kewangkewang
FunlidayFunliday kewangkewang
coscupcoscup '20'20
mopconmopcon '14 '20'14 '20

3.
4
推薦景點

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5
推薦景點

5.
6
推薦景點

6.
7
推薦景點

7.
8
技術演進

8.
9
V1 2019-02

9.
10
Summary V1 2019-02

10.
11
Summary
● GiST index
V1 2019-02

11.
12
Summary
● GiST index
● Cluster
V1 2019-02

12.
13
Summary
● GiST index
● Cluster
● Nearest-Neighbor Search
V1 2019-02

13.
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Summary
● GiST index
● Cluster
● Nearest-Neighbor Search
● Advisory lock
V1 2019-02

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Summary
● GiST index
● Cluster
● Nearest-Neighbor Search
● Advisory lock
● Cache
V1 2019-02

15.
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Sequence diagram

16.
17
Sequence diagram V1 2019-02
client AP Redis DB

17.
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Sequence diagram V1 2019-02
client AP Redis DB
get POIs

18.
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Sequence diagram V1 2019-02
client AP Redis DB
get POIs get cache from Redis

19.
20
Sequence diagram V1 2019-02
client AP Redis DB
get POIs get cache from Redis
return cache

20.
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Sequence diagram V1 2019-02
client AP Redis DB
get POIs get cache from Redis
return cacheif hits, return POIs

21.
22
Sequence diagram V1 2019-02
client AP Redis DB
get POIs get cache from Redis
return cacheif hits, return POIs
if misses, calculate POIs from DB

22.
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Sequence diagram V1 2019-02
client AP Redis DB
get POIs get cache from Redis
return cacheif hits, return POIs
if misses, calculate POIs from DB
return calculated results

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24
Sequence diagram V1 2019-02
client AP Redis DB
get POIs get cache from Redis
return cacheif hits, return POIs
if misses, calculate POIs from DB
return calculated results
store cache to Redis

24.
25
Sequence diagram V1 2019-02
client AP Redis DB
get POIs get cache from Redis
return cacheif hits, return POIs
if misses, calculate POIs from DB
return calculated results
store cache to Redis
store OK

25.
26
Sequence diagram V1 2019-02
client AP Redis DB
get POIs get cache from Redis
return cacheif hits, return POIs
if misses, calculate POIs from DB
return calculated results
store cache to Redis
store OK
return POIs

26.
27
Advisory lock

27.
28
Advisory lock
client
V1 2019-02
server

28.
29
Advisory lock
client
req A (search Taipei city)
V1 2019-02
server
T

29.
30
Advisory lock
client
req A (search Taipei city)
req B (search Taipei city)
V1 2019-02
server
calculate
T
T+1

30.
31
Advisory lock
client
req A (search Taipei city)
res B (data processing...)
req B (search Taipei city)
V1 2019-02
server
calculate
T
T+1
T+3

31.
32
Advisory lock
client
req A (search Taipei city)
res B (data processing...)
req B (search Taipei city)
res A (calculated)
V1 2019-02
server
calculate
T
T+1
T+3
T+10

32.
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Table DDL

33.
34
Table DDL V1 2019-02

34.
35
Cluster

35.
36
Before cluster V1 2019-02

36.
37
Before cluster - query plan V1 2019-02

37.
38
Statistical correlation V1 2019-02

38.
39
Statistical correlation V1 2019-02
correlation 愈接近 1 ，用 index 的成本愈低

39.
40
Statistical correlation V1 2019-02
correlation 愈接近 1 ，用 index 的成本愈低
如果沒有基本運算子就算不出 correlation

40.
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Running cluster V1 2019-02

41.
42
Running cluster - lock V1 2019-02

42.
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Running cluster - lock
● Rebuild table
V1 2019-02

43.
44
Running cluster - lock
● Rebuild table
– Access Exclusive Lock
V1 2019-02

44.
45
Running cluster - lock
● Rebuild table
– Access Exclusive Lock
● Rebuild index
V1 2019-02

45.
46
Running cluster - lock
● Rebuild table
– Access Exclusive Lock
● Rebuild index
– Access Share Lock
V1 2019-02

46.
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Running cluster - lock
● Rebuild table
– Access Exclusive Lock
● Rebuild index
– Access Share Lock
– Access Exclusive Lock
V1 2019-02

47.
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After cluster 1 V1 2019-02

48.
49
After cluster 1 - query plan V1 2019-02

49.
50
After cluster 1 - query plan V1 2019-02

50.
51
After cluster 2 V1 2019-02

51.
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After cluster 2 - query plan V1 2019-02

52.
53
After cluster 2 - query plan V1 2019-02

53.
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Nearest-Neighbor Search

54.
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Nearest-Neighbor Search 1 V1 2019-02

55.
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Nearest-Neighbor Search 1 V1 2019-02

56.
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Nearest-Neighbor Search 1 V1 2019-02
full table scan because of ST_Distance

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Nearest-Neighbor Search 2 V1 2019-02

58.
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Nearest-Neighbor Search 2 V1 2019-02

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Nearest-Neighbor Search 2 V1 2019-02
speed up because of ST_Expand

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Nearest-Neighbor Search 3 V1 2019-02

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Nearest-Neighbor Search 3 V1 2019-02

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Nearest-Neighbor Search 3 V1 2019-02
<-> KNN

63.
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V2 2019-09 late

64.
65
Summary V2 2019-09 late

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Summary
● Use POI history to more precise
V2 2019-09 late

66.
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Summary
● Use POI history to more precise
● Remove duplicate POI from KNN and POI history via uniq
function
V2 2019-09 late

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V2.1 2020-06 late

68.
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Summary V2.1 2020-06 late

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Summary
● Extract city_data (2000M) from poi_data (25000M) to speed up
V2.1 2020-06 late

70.
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V2.2 2020-07 late

71.
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Summary V2.2 2020-07 late

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Summary
● Remove unnecessary OSM POI
V2.2 2020-07 late

73.
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Summary
● Remove unnecessary OSM POI
– drinking_water
V2.2 2020-07 late

74.
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Summary
● Remove unnecessary OSM POI
– drinking_water
– place_of_worship
V2.2 2020-07 late

75.
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Summary
● Remove unnecessary OSM POI
– drinking_water
– place_of_worship
– basketball, football, volleyball
V2.2 2020-07 late

76.
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Summary
● Remove unnecessary OSM POI
– drinking_water
– place_of_worship
– basketball, football, volleyball
– parking
V2.2 2020-07 late

77.
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Summary
● Remove unnecessary OSM POI
– drinking_water
– place_of_worship
– basketball, football, volleyball
– parking
● Expired time
V2.2 2020-07 late

78.
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Summary
● Remove unnecessary OSM POI
– drinking_water
– place_of_worship
– basketball, football, volleyball
– parking
● Expired time
– KNN cache has expired after 14d
V2.2 2020-07 late

79.
80
Summary
● Remove unnecessary OSM POI
– drinking_water
– place_of_worship
– basketball, football, volleyball
– parking
● Expired time
– KNN cache has expired after 14d
– POI history cache has expired after 1d
V2.2 2020-07 late

80.
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V3 2020-09-22 late

81.
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Summary V3 2020-09-22 late

82.
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Summary
● Read Redis at first, if not exists, set refresh true
V3 2020-09-22 late

83.
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Summary
● Read Redis at first, if not exists, set refresh true
● Read DB second, if not exists, calculate and store DB & Redis
V3 2020-09-22 late

84.
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Summary
● Read Redis at first, if not exists, set refresh true
● Read DB second, if not exists, calculate and store DB & Redis
● Set instead of uniq function
V3 2020-09-22 late

85.
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Summary
● Read Redis at first, if not exists, set refresh true
● Read DB second, if not exists, calculate and store DB & Redis
● Set instead of uniq function
● L2 & L3 cache
V3 2020-09-22 late

86.
87
Summary
● Read Redis at first, if not exists, set refresh true
● Read DB second, if not exists, calculate and store DB & Redis
● Set instead of uniq function
● L2 & L3 cache
● Refresher to scan refresh true and calculate
V3 2020-09-22 late

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Sequence diagram - API

88.
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Sequence diagram - API
client AP RedisDB
V3 2020-09-22 late

89.
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Sequence diagram - API
client AP RedisDB
get POIs
V3 2020-09-22 late

90.
91
Sequence diagram - API
client AP RedisDB
get POIs get cache
V3 2020-09-22 late

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92
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
V3 2020-09-22 late

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93
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
V3 2020-09-22 late

93.
94
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
V3 2020-09-22 late

94.
95
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
V3 2020-09-22 late

95.
96
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
V3 2020-09-22 late

96.
97
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
V3 2020-09-22 late
return cache

97.
98
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
if hits, return POIs
V3 2020-09-22 late
return cache

98.
99
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
if hits, return POIs
V3 2020-09-22 late
if misses, calculate POIs
return cache

99.
100
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
if hits, return POIs
V3 2020-09-22 late
if misses, calculate POIs
return cache
return POI IDs

100.
101
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
if hits, return POIs
V3 2020-09-22 late
if misses, calculate POIs
return cache
return POI IDs
store cache

101.
102
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
if hits, return POIs
V3 2020-09-22 late
if misses, calculate POIs
return cache
return POI IDs
store cache
store OK

102.
103
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
if hits, return POIs
V3 2020-09-22 late
if misses, calculate POIs
return cache
return POI IDs
store cache
store cache
store OK

103.
104
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
if hits, return POIs
V3 2020-09-22 late
if misses, calculate POIs
return cache
return POI IDs
store cache
store cache
store OK
store OK

104.
105
Sequence diagram - API
client AP RedisDB
get POIs get cache
return cache
if hits, return POIs
if misses, set refresh=true
set OK
get cache
if hits, return POIs
V3 2020-09-22 late
if misses, calculate POIs
return cache
return POI IDs
store cache
store cache
return POIs
store OK
store OK

105.
106
Sequence diagram - refresher

106.
107
Sequence diagram - refresher
city IDs refresher RedisDB
V3 2020-09-22 late

107.
108
Sequence diagram - refresher
city IDs refresher RedisDB
run
V3 2020-09-22 late

108.
109
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
V3 2020-09-22 late

109.
110
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
return POI IDs
V3 2020-09-22 late

110.
111
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
return POI IDs
store cache
V3 2020-09-22 late

111.
112
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
return POI IDs
store cache
store OK
V3 2020-09-22 late

112.
113
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
return POI IDs
store cache
store OK
V3 2020-09-22 late
store cache

113.
114
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
return POI IDs
store cache
store OK
V3 2020-09-22 late
store cache
store OK

114.
115
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
return POI IDs
store cache
store OK
V3 2020-09-22 late
store cache
store OK
set refresh=false

115.
116
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
return POI IDs
store cache
store OK
V3 2020-09-22 late
store cache
store OK
set refresh=false
set OK

116.
117
Sequence diagram - refresher
city IDs refresher RedisDB
run calculate POIs
return POI IDs
store cache
store OK
done
V3 2020-09-22 late
store cache
store OK
set refresh=false
set OK

117.
118
V3.1 2020-09-23 early

118.
119
Summary V3.1 2020-09-23 early

119.
120
Summary
● Store back existing cache from Redis to DB
V3.1 2020-09-23 early

120.
121
Sequence diagram

121.
122
Sequence diagram
client AP RedisDB
V3.1 2020-09-23 early

122.
123
Sequence diagram
client AP RedisDB
run
V3.1 2020-09-23 early

123.
124
Sequence diagram
client AP RedisDB
run get cache
V3.1 2020-09-23 early

124.
125
Sequence diagram
client AP RedisDB
run get cache
return cache
V3.1 2020-09-23 early

125.
126
Sequence diagram
client AP RedisDB
run get cache
return cache
if hits, get cache
V3.1 2020-09-23 early

126.
127
Sequence diagram
client AP RedisDB
run get cache
return cache
if hits, get cache
return cache
V3.1 2020-09-23 early

127.
128
Sequence diagram
client AP RedisDB
run get cache
return cache
if hits, get cache
return cache
if misses, store cache
V3.1 2020-09-23 early

128.
129
Sequence diagram
client AP RedisDB
run get cache
return cache
if hits, get cache
return cache
if misses, store cache
store OK
V3.1 2020-09-23 early

129.
130
Sequence diagram
client AP RedisDB
run get cache
return cache
if hits, get cache
return cache
done
if misses, store cache
store OK
V3.1 2020-09-23 early

130.
131
V3.2 2020-09-23 mid

131.
132
Summary V3.2 2020-09-23 mid

132.
133
Summary
● POI history cache TTL from 1d to 14d
V3.2 2020-09-23 mid

133.
134
Summary
● POI history cache TTL from 1d to 14d
– Balance diversity
V3.2 2020-09-23 mid

134.
135
Summary
● POI history cache TTL from 1d to 14d
– Balance diversity
– Flatten burst activities
V3.2 2020-09-23 mid

135.
136
Heatmap

136.
137
Heatmap V3.2 2020-09-23 mid

137.
138
V3.3 2020-09-24 early

138.
139
Summary V3.3 2020-09-24 early

139.
140
Summary
● Measure execution time
V3.3 2020-09-24 early

140.
141
Summary
● Measure execution time
– Add New Relic custom attribute
V3.3 2020-09-24 early

141.
142
New Relic custom attributes

142.
143
New Relic custom attributes V3.3 2020-09-24 early

143.
144
New Relic custom attributes V3.3 2020-09-24 early

144.
145
New Relic custom attributes V3.3 2020-09-24 early

145.
146
V3.4 2020-09-24 mid

146.
147
Summary V3.4 2020-09-24 mid

147.
148
Summary
● Add result cache for language code and city id at AP
V3.4 2020-09-24 mid

148.
149
Summary
● Add result cache for language code and city id at AP
● Measure execution time
V3.4 2020-09-24 mid

149.
150
Summary
● Add result cache for language code and city id at AP
● Measure execution time
– Add New Relic custom segment
V3.4 2020-09-24 mid

150.
151
Sequence diagram

151.
152
Sequence diagram
client AP DBLRU cache
(with POI IDs, city ID,language)
V3.4 2020-09-24 mid
(at AP)

152.
153
Sequence diagram
client AP DBLRU cache
get results
(with POI IDs, city ID,language)
V3.4 2020-09-24 mid
(at AP)

153.
154
Sequence diagram
client AP DBLRU cache
get results
(with POI IDs, city ID,language)
return results
V3.4 2020-09-24 mid
(at AP)

154.
155
Sequence diagram
client AP DBLRU cache
get results
if hits, return POIs
(with POI IDs, city ID,language)
return results
V3.4 2020-09-24 mid
(at AP)

155.
156
Sequence diagram
client AP DBLRU cache
get results
if hits, return POIs
if misses, build results
(with POI IDs, city ID,language)
return results
V3.4 2020-09-24 mid
(at AP)

156.
157
Sequence diagram
client AP DBLRU cache
get results
if hits, return POIs
if misses, build results
return results
(with POI IDs, city ID,language)
return results
V3.4 2020-09-24 mid
(at AP)

157.
158
Sequence diagram
client AP DBLRU cache
get results
if hits, return POIs
if misses, build results
return results
store results
(with POI IDs, city ID,language)
return results
V3.4 2020-09-24 mid
(at AP)

158.
159
Sequence diagram
client AP DBLRU cache
get results
if hits, return POIs
if misses, build results
return results
store results
store OK
(with POI IDs, city ID,language)
return results
V3.4 2020-09-24 mid
(at AP)

159.
160
Sequence diagram
client AP DBLRU cache
get results
if hits, return POIs
if misses, build results
return results
store results
return POIs store OK
(with POI IDs, city ID,language)
return results
V3.4 2020-09-24 mid
(at AP)

160.
161
New Relic custom segments

161.
162
Before custom segments V3.4 2020-09-24 mid

162.
163
After custom segments V3.4 2020-09-24 mid

163.
164
After custom segments V3.4 2020-09-24 mid

164.
165
V3.5 2020-09-24 late

165.
166
Summary V3.5 2020-09-24 late

166.
167
Summary
● Merge join: 70s
V3.5 2020-09-24 late

167.
168
Summary
● Merge join: 70s
– where and group together
V3.5 2020-09-24 late

168.
169
Summary
● Merge join: 70s
– where and group together
● Hash join: 10s
V3.5 2020-09-24 late

169.
170
Summary
● Merge join: 70s
– where and group together
● Hash join: 10s
– where first then group
V3.5 2020-09-24 late

170.
171
Merge join

171.
172
Before optimization: 70s V3.5 2020-09-24 late

172.
173
Before optimization: 70s V3.5 2020-09-24 late

173.
174
Before optimization: 70s V3.5 2020-09-24 late
https://explain.depesz.com/s/Om1c

174.
175
Before optimization: 70s V3.5 2020-09-24 late

175.
176
Before optimization: 70s V3.5 2020-09-24 late

176.
177
Hash join

177.
178
After optimization: 10s V3.5 2020-09-24 late

178.
179
After optimization: 10s V3.5 2020-09-24 late

179.
180
After optimization: 10s V3.5 2020-09-24 late
https://explain.depesz.com/s/C9yZ

180.
181
After optimization: 10s V3.5 2020-09-24 late

181.
182
After optimization: 10s V3.5 2020-09-24 late

182.
183
V3.6 2020-09-25 early

183.
184
Summary V3.6 2020-09-25 early

184.
185
Summary
● Remove duplicate middleware: 1ms
V3.6 2020-09-25 early

185.
186
V3.7 2020-09-27 early

186.
187
Summary V3.7 2020-09-27 early

187.
188
Summary
● Find city from location via GiST index
V3.7 2020-09-27 early

188.
189
Summary
● Find city from location via GiST index
● Query POI history via B-tree index
V3.7 2020-09-27 early

189.
190
GiST index

190.
191
Find city from location V3.7 2020-09-27 early

191.
192
Before optimization: 400ms V3.7 2020-09-27 early

192.
193
Before optimization: 400ms V3.7 2020-09-27 early

193.
194
Before optimization: 400ms V3.7 2020-09-27 early
https://explain.depesz.com/s/y5Vv

194.
195
Create GiST index V3.7 2020-09-27 early

195.
196
After optimization: 0.4ms V3.7 2020-09-27 early

196.
197
After optimization: 0.4ms V3.7 2020-09-27 early

197.
198
After optimization: 0.4ms V3.7 2020-09-27 early
https://explain.depesz.com/s/QqmT

198.
199
B-tree index

199.
200
Query POI history V3.7 2020-09-27 early

200.
201
Before optimization: 10s V3.7 2020-09-27 early

201.
202
Before optimization: 10s V3.7 2020-09-27 early

202.
203
Before optimization: 10s V3.7 2020-09-27 early
https://explain.depesz.com/s/7LHy

203.
204
Create B-tree index V3.7 2020-09-27 early

204.
205
After optimization: 1s V3.7 2020-09-27 early

205.
206
After optimization: 1s V3.7 2020-09-27 early

206.
207
After optimization: 1s V3.7 2020-09-27 early
https://explain.depesz.com/s/o59U

207.
208
References
● digoal/blog
● PostgreSQL cluster table using index
● 27. Nearest-Neighbour Searching - Introduction to PostGIS

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