feat(influx_tools): Add export to parquet files

[srebhan]

Closes #
Superseeds #25253

Describe your proposed changes here.

• I've read the contributing section of the project README.
• Signed CLA (if not already signed).

This PR adds a command to export data into per-shard parquet files. To do so, the command iterates over the shards, creates a cumulative schema over the series of a measurement (i.e. a super-set of tags and fields) and exports the data to a parquet file per measurement and shard.

To test the tool run

go run -ldflags "-X google.golang.org/protobuf/reflect/protoregistry.conflictPolicy=ignore" ./cmd/influx_tools/ export-parquet -config influxdb.conf -database telegraf

[davidby-influx]

I did a quick review, but I'm not familiar with arrow and certainly missed some things. I can do a more thorough review if we paired to walk through the algorithm once.

[srebhan]

@davidby-influx thanks for the thorough review! I tried to address all issues and commented on the three unresolved ones. Will schedule a meeting for walking through the code. Thanks again!

[davidby-influx]

LGTM

[alespour]

I'm not sure what to make of this: I have v1 db with several measurements like cpu disk etc, each with ~8M rows

> select count(usage_user) from cpu

name: cpu
time count
---- -----
0    8631360

The same query returns different number of rows in exported Parquet "db":

alespour@master-node:/bigdata/x$ duckdb -column -s "select count(usage_user) from 'all/cpu-*.parquet'"

count(usage_user)
-----------------
28771200 

Log attached.
cpu-export.log

[alespour]

• tested measurement without tags - OK
• tested single & all measurements export - OK, except the discrepancy of number of rows

Tested with db with simulating 1-month of monitoring data of a small data center (9 measurements like cpu, disk etc, 10 tags). DB files size on disk 4.1 GB, 5 shards.

Exported Parquet size on disk 11 GB, took 1h6m on somewhat obsolete laptop (Core i7 CPU, 8-core, 16 GB RAM, SSD). Memory usage during export was stable (RSS peak ~2 GB).

InfluxDB measuement structure example:

> show tag keys from cpu
name: cpu
tagKey
------
arch
datacenter
hostname
os
rack
region
service
service_environment
service_version
team

> show field keys from cpu
name: cpu
fieldKey         fieldType
--------         ---------
usage_guest      float
usage_guest_nice float
usage_idle       float
usage_iowait     float
usage_irq        float
usage_nice       float
usage_softirq    float
usage_steal      float
usage_system     float
usage_user       float

Parquet:

alespour@master-node:/bigdata/x$ duckdb -column -s "describe select * from 'all/cpu-*.parquet'"

column_name          column_type  null  key  default  extra
-------------------  -----------  ----  ---  -------  -----
time                 TIMESTAMP    YES                      
arch                 VARCHAR      YES                      
datacenter           VARCHAR      YES                      
hostname             VARCHAR      YES                      
os                   VARCHAR      YES                      
rack                 VARCHAR      YES                      
region               VARCHAR      YES                      
service              VARCHAR      YES                      
service_environment  VARCHAR      YES                      
service_version      VARCHAR      YES                      
team                 VARCHAR      YES                      
usage_guest          DOUBLE       YES                      
usage_guest_nice     DOUBLE       YES                      
usage_idle           DOUBLE       YES                      
usage_iowait         DOUBLE       YES                      
usage_irq            DOUBLE       YES                      
usage_nice           DOUBLE       YES                      
usage_softirq        DOUBLE       YES                      
usage_steal          DOUBLE       YES                      
usage_system         DOUBLE       YES                      
usage_user           DOUBLE       YES                      

Measurement without tags:

alespour@master-node:/bigdata/x$ duckdb -column -s "select * from 'notags/*.parquet'"
time                        lat    lon  
--------------------------  -----  -----
2024-10-02 13:03:55.643371  49.95  14.47
2024-10-02 13:04:04.423014  49.91  14.49
2024-10-02 13:04:12.726653  49.94  14.53

[alespour]

I will repeat the test to verify the number of rows (mis)match.

[alespour]

My apologies, it was a mistake on my side. Row count matches.

InfluxDB:

> select count(usage_user) from cpu
name: cpu
time count
---- -----
0    28771200

Parquet:

alespour@master-node:/bigdata/x$ duckdb -column -s "select count(usage_user) from 'cpu/*.parquet'"
count(usage_user)
-----------------
28771200  

[alespour]

• tested other types - OK

Creating the following schemata for 1 measurement(s):
  Measurement "types" with 0 tag(s) and  5 field(s):
    Column	Kind		Datatype
    ------	----		--------
    time	timestamp	timestamp (nanosecond)
    label	field		string
    lat		field		float
    lon		field		float
    match	field		boolean
    scale	field		integer

alespour@master-node:/bigdata/x$ sudo duckdb -column -s "describe from 'types/*.parquet'"
column_name  column_type  null  key  default  extra
-----------  -----------  ----  ---  -------  -----
time         TIMESTAMP    YES                      
label        VARCHAR      YES                      
lat          DOUBLE       YES                      
lon          DOUBLE       YES                      
match        BOOLEAN      YES                      
scale        BIGINT       YES

alespour@master-node:/bigdata/x$ sudo duckdb -column -s "select * from 'types/*.parquet' limit 1"
time                        label  lat    lon    match  scale
--------------------------  -----  -----  -----  -----  -----
2024-10-03 07:58:33.419431  a1     49.94  14.53  true   4    

[alespour]

It's GTG by me 👍