README
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Ledger example
Summary
Simulate a ledger and a certain type of workload against it. A general ledger is a complete record of financial transactions over the life of a bank (or other company). The example here aims to model a bank in a more realistic setting than our previous bank example(s) do, and tickles contention issues (causing complete deadlock in the more contended modes) which will be interesting to investigate.
Running
See the bank example for more detailed information. The example may be run both against Postgres and Cockroach.
Run the example with --help to see all configuration options.
Prerequisites
./cockroach start --background # for CockroachDB
docker run -d -p 5432:5432 postgres # for Postgres
Examples
For Postgres, change 26257 to 5432 below.
go run $GOPATH/src/github.com/cockroachdb/examples-go/ledger/main.go --concurrency 5 --sources 10 --destinations 10 postgres://root@localhost:26257?sslmode=disable
This runs a moderately contended example, transferring money between ten random accounts. You can vary the contention by source and destination:
- no contention:
--sources=0,--destinations=0. - asymmetric contention: money is transferred from (practically infinitely) many
accounts to ten destinations accounts:
--sources=0,--destinations=10 - hammering a single account, but only using 100 source accounts:
--sources=100,--destinations=1.
The workload is essentially a read for both the source and target account, and then a write to both the source and target account. Hence, you should expect some symmetry, but since the source account is accessed first for both the read and the write, it's not perfectly symmetric.
Documentation
Source Files