Compression does not work

[alexey-milovidov]

What type of bug is this?

Configuration

What subsystems and features are affected?

Compression

What happened?

I'm setting up TimescaleDB with hypertables and compression on a clean VM:

#!/bin/bash

# Install

sudo apt-get update
sudo apt install gnupg postgresql-common apt-transport-https lsb-release wget
sudo /usr/share/postgresql-common/pgdg/apt.postgresql.org.sh
sudo bash -c 'echo "deb https://packagecloud.io/timescale/timescaledb/ubuntu/ $(lsb_release -c -s) main" > /etc/apt/sources.list.d/timescaledb.list'
wget --quiet -O - https://packagecloud.io/timescale/timescaledb/gpgkey | sudo apt-key add -
sudo apt-get update
sudo apt install timescaledb-2-postgresql-14
sudo bash -c "echo \"shared_preload_libraries = 'timescaledb'\" >> /etc/postgresql/14/main/postgresql.conf"
sudo systemctl restart postgresql

sudo -u postgres psql -c "CREATE DATABASE test"
sudo -u postgres psql test -c "CREATE EXTENSION IF NOT EXISTS timescaledb"

# Import the data

wget 'https://datasets.clickhouse.com/hits_compatible/hits.tsv.gz'
gzip -d hits.tsv.gz
chmod 777 ~ hits.tsv

sudo -u postgres psql test < create.sql
sudo -u postgres psql test -c "SELECT create_hypertable('hits', 'eventtime')"
sudo -u postgres psql test -c "CREATE INDEX ix_counterid ON hits (counterid)"
sudo -u postgres psql test -c "ALTER TABLE hits SET (timescaledb.compress, timescaledb.compress_orderby = 'counterid, eventdate, userid, eventtime')"
sudo -u postgres psql test -c "SELECT add_compression_policy('hits', INTERVAL '1s')"

sudo -u postgres psql test -t -c '\timing' -c "\\copy hits FROM 'hits.tsv'"

# 1619875.288 ms (26:59.875)

sudo du -bcs /var/lib/postgresql/14/main/

But the data size is identical to Postgres: 72 GB

create.sql:

CREATE TABLE hits
(
    WatchID BIGINT NOT NULL,
    JavaEnable SMALLINT NOT NULL,
    Title TEXT NOT NULL,
    GoodEvent SMALLINT NOT NULL,
    EventTime TIMESTAMP NOT NULL,
    EventDate Date NOT NULL,
    CounterID INTEGER NOT NULL,
    ClientIP INTEGER NOT NULL,
    RegionID INTEGER NOT NULL,
    UserID BIGINT NOT NULL,
    CounterClass SMALLINT NOT NULL,
    OS SMALLINT NOT NULL,
    UserAgent SMALLINT NOT NULL,
    URL TEXT NOT NULL,
    Referer TEXT NOT NULL,
    IsRefresh SMALLINT NOT NULL,
    RefererCategoryID SMALLINT NOT NULL,
    RefererRegionID INTEGER NOT NULL,
    URLCategoryID SMALLINT NOT NULL,
    URLRegionID INTEGER NOT NULL,
    ResolutionWidth SMALLINT NOT NULL,
    ResolutionHeight SMALLINT NOT NULL,
    ResolutionDepth SMALLINT NOT NULL,
    FlashMajor SMALLINT NOT NULL,
    FlashMinor SMALLINT NOT NULL,
    FlashMinor2 TEXT NOT NULL,
    NetMajor SMALLINT NOT NULL,
    NetMinor SMALLINT NOT NULL,
    UserAgentMajor SMALLINT NOT NULL,
    UserAgentMinor VARCHAR(255) NOT NULL,
    CookieEnable SMALLINT NOT NULL,
    JavascriptEnable SMALLINT NOT NULL,
    IsMobile SMALLINT NOT NULL,
    MobilePhone SMALLINT NOT NULL,
    MobilePhoneModel TEXT NOT NULL,
    Params TEXT NOT NULL,
    IPNetworkID INTEGER NOT NULL,
    TraficSourceID SMALLINT NOT NULL,
    SearchEngineID SMALLINT NOT NULL,
    SearchPhrase TEXT NOT NULL,
    AdvEngineID SMALLINT NOT NULL,
    IsArtifical SMALLINT NOT NULL,
    WindowClientWidth SMALLINT NOT NULL,
    WindowClientHeight SMALLINT NOT NULL,
    ClientTimeZone SMALLINT NOT NULL,
    ClientEventTime TIMESTAMP NOT NULL,
    SilverlightVersion1 SMALLINT NOT NULL,
    SilverlightVersion2 SMALLINT NOT NULL,
    SilverlightVersion3 INTEGER NOT NULL,
    SilverlightVersion4 SMALLINT NOT NULL,
    PageCharset TEXT NOT NULL,
    CodeVersion INTEGER NOT NULL,
    IsLink SMALLINT NOT NULL,
    IsDownload SMALLINT NOT NULL,
    IsNotBounce SMALLINT NOT NULL,
    FUniqID BIGINT NOT NULL,
    OriginalURL TEXT NOT NULL,
    HID INTEGER NOT NULL,
    IsOldCounter SMALLINT NOT NULL,
    IsEvent SMALLINT NOT NULL,
    IsParameter SMALLINT NOT NULL,
    DontCountHits SMALLINT NOT NULL,
    WithHash SMALLINT NOT NULL,
    HitColor CHAR NOT NULL,
    LocalEventTime TIMESTAMP NOT NULL,
    Age SMALLINT NOT NULL,
    Sex SMALLINT NOT NULL,
    Income SMALLINT NOT NULL,
    Interests SMALLINT NOT NULL,
    Robotness SMALLINT NOT NULL,
    RemoteIP INTEGER NOT NULL,
    WindowName INTEGER NOT NULL,
    OpenerName INTEGER NOT NULL,
    HistoryLength SMALLINT NOT NULL,
    BrowserLanguage TEXT NOT NULL,
    BrowserCountry TEXT NOT NULL,
    SocialNetwork TEXT NOT NULL,
    SocialAction TEXT NOT NULL,
    HTTPError SMALLINT NOT NULL,
    SendTiming INTEGER NOT NULL,
    DNSTiming INTEGER NOT NULL,
    ConnectTiming INTEGER NOT NULL,
    ResponseStartTiming INTEGER NOT NULL,
    ResponseEndTiming INTEGER NOT NULL,
    FetchTiming INTEGER NOT NULL,
    SocialSourceNetworkID SMALLINT NOT NULL,
    SocialSourcePage TEXT NOT NULL,
    ParamPrice BIGINT NOT NULL,
    ParamOrderID TEXT NOT NULL,
    ParamCurrency TEXT NOT NULL,
    ParamCurrencyID SMALLINT NOT NULL,
    OpenstatServiceName TEXT NOT NULL,
    OpenstatCampaignID TEXT NOT NULL,
    OpenstatAdID TEXT NOT NULL,
    OpenstatSourceID TEXT NOT NULL,
    UTMSource TEXT NOT NULL,
    UTMMedium TEXT NOT NULL,
    UTMCampaign TEXT NOT NULL,
    UTMContent TEXT NOT NULL,
    UTMTerm TEXT NOT NULL,
    FromTag TEXT NOT NULL,
    HasGCLID SMALLINT NOT NULL,
    RefererHash BIGINT NOT NULL,
    URLHash BIGINT NOT NULL,
    CLID INTEGER NOT NULL
);

Note: I also found that the documentation on the website is incorrect, because the installation steps missing

sudo bash -c "echo \"shared_preload_libraries = 'timescaledb'\" >> /etc/postgresql/14/main/postgresql.conf"

TimescaleDB version affected

latest as of today

PostgreSQL version used

14

What operating system did you use?

Ubuntu 22.04 x86

What installation method did you use?

Deb/Apt

What platform did you run on?

Amazon Web Services (AWS)

Relevant log output and stack trace

No response

How can we reproduce the bug?

You just repeat the steps from above.

[konskov]

Hello @alexey-milovidov , thank you for reaching out. It looks like you have added a compression policy to compress the data in your hypertable. It seems likely that the policy simply hasn't run yet to compress the data, as by default the policy is scheduled to run after 24 hours. Could you try and manually compress with compress_chunk, and let us know if you get better results? Thanks!

[alexey-milovidov]

Ok, I will try to do it.

[alexey-milovidov]

Yes, the problem is solved. Queries are run faster.