sequence.txt

title Mostly real-time SQLite in Lambda

participant "Browser" as b
participant "Lambda" as l
participant S3
participant "DynamoDB" as ddb

b->l:query "select title from books where id = 15"
l->S3:GetObject(key=db.sqlite, version=abc)
rbox right of S3:takes ~500ms for 100MB
l<-S3:base sqlite db
note over l:sqlite3_open()
l->ddb:Query(key={pk=changesets}, startKey=null)
l<-ddb:changesets applicable to base sqlite db
note over l:sqlite3changeset_apply()
note over l:sqlite3_step() for each row
b<-l:json array of row objects

space

b->l:query "insert into books ..."
l->ddb:Query(key={pk=changesets}, startKey=startKey={pk=changesets, sk=ulid_from_last_changeset})
l<-ddb:changesets applicable to base sqlite db
note over l:sqlite3changeset_apply()
note over l:sqlite3_step()
note over l:sqlite3session_changeset()
l->ddb:PutItem(item={pk=changesets, sk=ulid, bin=changeset}}


==some time passes, this gets served by a different lambda container==

b->l:query "select title from books where id = 19"
l->ddb:Query(key={pk=changesets}, startKey={pk=changesets, sk=ulid_from_last_changeset})
rbox right of ddb:takes ~4ms
l<-ddb:changesets applicable to base sqlite db
note over l:sqlite3changeset_apply()
note over l:sqlite3_step() for each row
b<-l:json array of row objects