What Is Mercari? ! Service start: July 2013 ! OS: Android, iOS *Can also be accessed by web browsers ! Usage fee: Free *Commission fee for sold items: 10% of the sales price ! Regions/languages supported: Base specs for Japan/Japanese !Total number of listings to date: More than 1.5 billion Many sellers enjoy having the items they no longer need purchased and used by buyers who need them, and buyers enjoy the feeling of hunting for treasure as they search through unique and diverse items for lucky finds. In addition to buying and selling, users actively communicate through the buyer/seller chat and the “Like” feature. The Mercari app is a C2C marketplace where individuals can easily sell used items. We want to provide both buyers and sellers with a service where they can enjoy safe and secure transactions. Mercari offers a unique customer experience, with a transaction environment that uses the payments Mercari holds in escrow, and simple and affordable shipping options.
Fastly Image Optimizer in Mercari US • Originally, we used an internal image conversion proxy in Go
• To resize, crop, convert format, … on-the-fly
• We switched to Fastly Image Optimizer in 2018
• Fastly VCL was useful to keep the original manipulation rule at that time
• sub vcl_recv { # absorb the difference between our proxy and Image Optimizer … set req.url = regsub(req.url, “([&\?])w=([0-9]+)”, “\1width=\2”); set req.url = regsub(req.url, “([&\?])h=([0-9]+)”, “\1height=\2”); set req.url = regsub(req.url, “([&\?])fmt=([a-z]+)”, “\1format=\2”); … }
Sandwich Shielding POP between Edge POP and Origin Edge POP Edge POP Edge POP Shielding POP ImageFlux Amazon S3 Cache Hit on Edge POP Cache Hit on Shielding POP Cache Miss
CHR CalculationʢIf Shielding is enabledʣ Cache Hit Ratio(True) = (1 − miss − shield requests − shield ) × 100 miss: Number of cache misses
shield: Number of requests from edge to the shield POP
requests: Number of Requests Processed The truth about cache hit ratios: https://www.fastly.com/blog/truth-about-cache-hit-ratios * Taking no account of number of some states like pass
Impact of Origin Shielding • Mercari Image Delivery’s Cache Hit Ratio improves significantly
• In approximately,
• JP: 96.x% -> 98.x%
• US: 60~70+% -> 80~90+% CHR for a given month when Shielding is enabled Cache Hit Rate(Edge): hit_ratio in Historical Stats Cache Hit Rate(True): CHR with Shielding
100k size objects started to increase 1kɿ~1KB 10kɿ1KB~10KB 100kɿ10KB~100KB 1mɿ100KB~1MB 10mɿ1MB~10MB 100mɿ10MB~100MB 1gɿ100MB~1GB It’s useful to know the image size distribution
100k size objects started to increase 1kɿ~1KB 10kɿ1KB~10KB 100kɿ10KB~100KB 1mɿ100KB~1MB 10mɿ1MB~10MB 100mɿ10MB~100MB 1gɿ100MB~1GB It’s useful to know the image size distribution Detected and fixed the cause
100k size objects started to increase Detected and fixed the cause The cause was that JPEG is delivered instead of WebP in some microservices 1kɿ~1KB 10kɿ1KB~10KB 100kɿ10KB~100KB 1mɿ100KB~1MB 10mɿ1MB~10MB 100mɿ10MB~100MB 1gɿ100MB~1GB It’s useful to know the image size distribution
cubicdaiya
carta_engineering
you
_kensh
bitkey
newrelic2023
keithyokoma
hikarut
washizaki
nyankotaro
sue445
startree
victorrentea
caitiem20
destraynor
eitanlees
wjessup
marcelosomers
sonatard
chriscoyier
jeffersonlam
zakiwarfel
danielanewman
pedronauck
brad_frost