During the Distributed SQL Summit I've explained how YugabyteDB writes the SQL transaction provisional records to the IntentsDB and then to the RegularDB. For the demo, I started, in a Docker container, a single-node YugabyteDB cluster with TEST_docdb_log_write_batches enabled to log the write operations:
docker run -it \
-p7000:7000 -p9000:9000 -p15433:15433 -p5433:5433 \
yugabytedb/yugabyte:latest bash
yugabyted start --ui=false --listen=0.0.0.0 \
--tserver_flags="\
TEST_docdb_log_write_batches=true,\
yb_enable_read_committed_isolation=true,\
tserver_enable_metrics_snapshotter=false\
"
tail -n 1000 -F /root/var/logs/tserver/yb-tserver.*log.INFO.* |\
grep -vE '(DEBUG: Closing|Time spent)' &
I tailed the logfile in the background and this is what you see during the demo:
If you want to reproduce it, here are the commands I've run.
Lab: non-transactional on colocated
ysqlsh -h $(hostname)
create database franck with colocation=true;
\c franck
create table cities (name text primary key, country text)
;
insert into cities values ('Geneva','Switzerland')
;
Lab: delete is transactional
delete from cities
;
Lab: SQL transactions
begin transaction
;
insert into cities values ('Geneva','Switzerland')
;
insert into cities values ('Lausanne','Switzerland')
;
commit
;
Lab: secondary index
insert into cities values ('Geneva','Switzerland')
;
create index cities_country on cities(country)
;
insert into cities values ('Lausanne','Switzerland')
;
Lab: non transactional
set yb_disable_transactional_writes = on
;
insert into cities values ('Lausanne','Switzerland')
;
Reminder: this is not to be used in production. The parameters that start with TEST are used for regression tests. You can use it in a lab to understand how it works.
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