I wrote the following query.
-- TB_PK_INDEX
CREATE TABLE TB_PRIMARY_INDEX
(
COL VARCHAR COLLATE pg_catalog."POSIX" NOT NULL
)
WITH (
OIDS=false
);
-- TB_PK_INDEX Primary Key
CREATE UNIQUE INDEX PK_TB_PRIMARY_INDEX
ON TB_PRIMARY_INDEX
( -- TB_PK_INDEX
COL COLLATE pg_catalog."POSIX" varchar_pattern_ops ASC
);
-- TB_PK_INDEX
ALTER TABLE TB_PRIMARY_INDEX
ADD CONSTRAINT PK_TB_PRIMARY_INDEX
PRIMARY KEY
USING INDEX PK_TB_PRIMARY_INDEX
NOT DEFERRABLE;
And the following error occurs.
SQL Error [42809]: Error: "pk_tb_primary_index" no primary sort method for index 1 column
Detail: Cannot create a primary key or unique constraint using such an index.
Test was conducted on PostgreSQL 14.2.. The concept of operator class is lacking. Please advise.
#Error description:
It's possible to create a table that has a foreign key into a hypertable provided the foreign key is defined when the table is created
#To Reproduce, there are next tables:
CREATE TABLE ids (
measurement_id int DEFAULT 0,
description text DEFAULT 0,
m_id bigserial NOT NULL,
service_id int DEFAULT NULL,
time bigint NOT NULL DEFAULT cast((EXTRACT(EPOCH FROM now() AT TIME ZONE 'UTC') * 1000) as bigint),
user_id int DEFAULT NULL,
end_time DOUBLE PRECISION DEFAULT 0,
start_time int NOT NULL DEFAULT 0
);
CREATE INDEX ON ids (time DESC, user_id);
CREATE INDEX ON ids (time DESC, service_id);
SELECT create_hypertable('ids', 'start_time', chunk_time_interval => 604800016);
---------
CREATE TABLE IF NOT EXISTS metrics (
id bigserial NOT NULL,
duration real DEFAULT NULL,
metric integer DEFAULT 0,
m_id bigint NOT NULL,
time bigint NOT NULL DEFAULT 0
);
ALTER TABLE metrics ADD PRIMARY KEY (time, m_id);
CREATE INDEX ON metrics (time DESC);
CREATE INDEX ON metrics (time DESC, measurement );
CREATE INDEX ON metrics (time DESC, m_id );
grant all privileges on ids, metrics to your_db_user;
SELECT create_hypertable('metrics', 'time' , chunk_time_interval => 604800016);
SELECT table_catalog, table_schema, table_name, privilege_type FROM information_schema.table_privileges WHERE grantee = 'your_db_user';
---------
DROP TABLE IF EXISTS resource;
CREATE TABLE resource(
id int NOT NULL,
cpu text DEFAULT 0,
storing text DEFAULT 0,
memory text DEFAULT 0
);
ALTER TABLE resource ADD PRIMARY KEY (id);
CREATE SEQUENCE resource_id_seq
INCREMENT 1
MINVALUE 1
MAXVALUE 2147483647
START 1
CACHE 1;
ALTER TABLE resource_id_seq
OWNER TO your_db_user;
ALTER TABLE resource ALTER COLUMN id SET DEFAULT nextval('resource_id_seq'::regclass);
---------
CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
DROP TABLE IF EXISTS ns;
CREATE TABLE ns(
id bigint NOT NULL,
uuid uuid NOT NULL DEFAULT uuid_generate_v4 (),
availability double precision,
faultTolerance boolean,
activated boolean,
UNIQUE (id, uuid),
PRIMARY KEY(id),
CONSTRAINT fk_resource
FOREIGN KEY(id)
REFERENCES resource(id)
ON DELETE CASCADE
);
CREATE SEQUENCE ns_id_seq
INCREMENT 1
MINVALUE 1
MAXVALUE 9223372036854775807
START 1
CACHE 1;
ALTER TABLE ns_id_seq
OWNER TO your_db_user;
ALTER TABLE ns ALTER COLUMN id SET DEFAULT nextval('ns_id_seq'::regclass);
---------
DROP TABLE IF EXISTS authentication;
CREATE TABLE authentication(
id integer NOT NULL,
username character varying(255) NOT NULL,
password character varying(255) NOT NULL,
host character varying(255) NOT NULL,
port character varying(10) NOT NULL,
PRIMARY KEY(id)
);
CREATE SEQUENCE auth_id_seq
INCREMENT 1
MINVALUE 1
MAXVALUE 2147483647
START 1
CACHE 1;
ALTER TABLE auth_id_seq
OWNER TO your_db_user;
ALTER TABLE authentication ALTER COLUMN id SET DEFAULT nextval('auth_id_seq'::regclass);
---------
DROP TABLE IF EXISTS job;
CREATE TABLE job(
id int NOT NULL,
interval integer NOT NULL,
auth_id integer REFERENCES authentication (id),
ns_id integer REFERENCES ns (id),
UNIQUE (auth_id, ns_id),
PRIMARY KEY(id)
);
ALTER TABLE job
ADD CONSTRAINT fk_auth_id
FOREIGN KEY (id) REFERENCES authentication (id)
ON DELETE CASCADE
DEFERRABLE INITIALLY DEFERRED;
ALTER TABLE job
ADD CONSTRAINT fk_ns_id
FOREIGN KEY (id) REFERENCES ns (id)
ON DELETE CASCADE
DEFERRABLE INITIALLY DEFERRED;
CREATE SEQUENCE job_id_seq
INCREMENT 1
MINVALUE 1
MAXVALUE 2147483647
START 1
CACHE 1;
ALTER TABLE job_id_seq
OWNER TO your_db_user;
ALTER TABLE job ALTER COLUMN id SET DEFAULT nextval('job_id_seq'::regclass);
---------
DROP TABLE IF EXISTS job_metric;
CREATE TABLE job_metric (
id int NOT NULL,
j_id int NOT NULL REFERENCES job (id),
mj_id bigint NOT NULL,
jm_time bigint NOT NULL
);
CREATE INDEX ON job_metric (jm_time DESC);
CREATE INDEX ON job_metric (jm_time DESC, id);
CREATE INDEX ON job_metric (jm_time DESC, mj_id);
ALTER TABLE job_metric ADD PRIMARY KEY (jm_time, id);
grant all privileges on job_metric to your_db_user;
SELECT create_hypertable('job_metric', 'jm_time' , chunk_time_interval => 604800016);
CREATE SEQUENCE mjob_metric_id_seq
INCREMENT 1
MINVALUE 1
MAXVALUE 2147483647
START 1
CACHE 1;
ALTER TABLE mjob_metric_id_seq
OWNER TO your_db_user;
ALTER TABLE job_metric ALTER COLUMN id SET DEFAULT nextval('mjob_metric_id_seq'::regclass);
---------
After creating the tables, I have used the solution proposed by #Laurenz in a database with PostgreSQL 12.6 using the extension of timescaledb 1.7.5 as follows:
#To fill the table with the appropriate values:
UPDATE job_metric AS jm_point
SET jm_time = qm.time
FROM metrics AS qm
WHERE qm.m_id = jm_point.mj_id;
#Then set it NOT NULL:
ALTER TABLE job_metric ALTER jm_time SET NOT NULL;
#To define your foreign key:
ALTER TABLE job_metric
ADD FOREIGN KEY (mj_id, jm_time)
REFERENCES metrics (time, m_id) MATCH FULL;
#Response of the last reference table to enable foreign key: Query returned successfully in 40 msec.
Expected behavior:
The idea is to use the table job_metric in an even many-to-many relationship to access the information of job and metrics tables.
Actual behavior and error:
Tables are created and FKs were created but cannot be used when data is inserted at job_metric as is detailed in the following:
INSERT INTO job_metric (j_id, mj_id, jm_time)
VALUES(13, 185063, 1621957192266);
ERROR: foreign keys to hypertables are not supported CONTEXT: SQL
statement " ALTER TABLE _timescaledb_internal._hyper_5_5_chunk ADD
CONSTRAINT "5_13_job_metric_j_id_mj_id_jm_time_fkey" FOREIGN KEY
(j_id, mj_id, jm_time) REFERENCES qmetrics("time", m_id) MATCH FULL "
PL/pgSQL function
_timescaledb_internal.chunk_constraint_add_table_constraint(_timescaledb_catalog.chunk_constraint)
line 42 at EXECUTE SQL state: 0A000
***According to https://docs.timescale.com/timescaledb/latest/overview/limitations/##distributed-hypertable-limitations, it looks like the above error is part of the hypertable limitations:
Foreign key constraints referencing a hypertable are not supported.
#Request:
Given the above information and errors, does anyone know any solution at the DB level to establish the relationships (many-to-many or one-to-many) using timescaledb extension and mainly hypertables?
Actually, I have obtained similar of above error when I had attempted to create many-to-many relation among the tables metrics and job_metric using the Django Rest Framework:
class Job_Metrics(models.Model):
job = models.OneToOneField(Job, on_delete=models.CASCADE)
metrics = models.ManyToManyField(Metrics)
time = models.IntegerField(default=0)
Running the application metrics pointing out directly metrics_db:
$ python3 manage.py migrate metrics --database=metrics_db
Operations to perform: Apply all migrations: metrics Running migrations: Applying
metrics.0002_job...Traceback (most recent call last): File
"/var/myproject/myprojectenv/lib/python3.8/site-packages/django/db/backends/utils.py",
line 84, in _execute return self.cursor.execute(sql, params)
psycopg2.errors.FeatureNotSupported: foreign keys to hypertables are
not supported
If someone knows a solution or has an idea to deal with the above error at the REST API level, please could you share your idea with the aim to access data associated tables (metrics and jobs) and modify them together when is required to delete e.g., a job_metric. So far, using hypertables amendments of timescaledb extension seems to be not a viable solution.
I have a question on the index for the following table.
create table ascertain_telephonenumbersmodel
(
id serial not null
constraint ascertain_telephonenumbersmodel_pkey
primary key,
abc_or_def smallint not null
constraint ascertain_telephonenumbersmodel_abc_or_def_check
check (abc_or_def >= 0),
numbers_range int4range not null,
volume smallint not null
constraint ascertain_telephonenumbersmodel_volume_check
check (volume >= 0),
operator varchar(50) not null,
region varchar(100) not null,
update_date timestamp with time zone not null,
);
The only one type of query this table is dealing with is
select
*
from
ascertain_telephonenumbersmodel
where
abc_or_def=`some integer` and numbers_range #> `some integer`
# example abc_or_def=900 and numbers_range #> 2685856
Question is – what is the best way of creating index for this condition?
DB – PostgreSQL 13
Number of rows ~ 400.000
Current execution time ~ 80-110 msec.
Thank you!
A compound gist index. You will need to use an extension to include the int in the index.
create extension btree_gist;
create index on ascertain_telephonenumbersmodel using gist (abc_or_def, numbers_range);
Using: Firebird 2.52
For performance of SELECT for the following query, do I require indexes on additional fields in my table:
Desired query:
select inventory_id, max(batch_no) from invty_batch
where inventory_id = :I
group by inventory_id
Table structure:
CREATE TABLE INVTY_BATCH (
ROW_ID INTEGER NOT NULL,
INVENTORY_ID INTEGER NOT NULL,
BATCH_NO VARCHAR(8) NOT NULL,
INVTYRCPT_ID INTEGER NOT NULL,
UNITPRICE NUMERIC(12, 2) DEFAULT 0.0 NOT NULL);
ALTER TABLE INVTY_BATCH ADD PRIMARY KEY (ROW_ID);
CREATE UNIQUE INDEX IXINVTYIDBATCHNO ON INVTY_BATCH(INVENTORY_ID,BATCH_NO);
Will creating indexes on inventory_id and batch_no columns benefit performance for the given query?
try to create an index for the field "batch_no", because the query is doing a search in this field.
PS : Use a desc index, because the search is for the max value
i have a table:
CREATE TABLE my_table
(
id integer NOT NULL DEFAULT nextval('seq_my_table_id'::regclass),
fk_id1 integer NOT NULL,
fk_id2 smallint NOT NULL,
name character varying(255) NOT NULL,
description text,
currency_name character varying(3) NOT NULL,
created timestamp with time zone NOT NULL DEFAULT now(),
updated timestamp with time zone NOT NULL DEFAULT now(),
CONSTRAINT "PK_my_table_id" PRIMARY KEY (id ),
CONSTRAINT "FK_my_table_fk_id1" FOREIGN KEY (fk_id1)
REFERENCES my_table2 (id) MATCH SIMPLE
ON UPDATE NO ACTION ON DELETE NO ACTION DEFERRABLE INITIALLY DEFERRED,
CONSTRAINT "FK_my_table_fk_id2" FOREIGN KEY (fk_id2)
REFERENCES my_table3 (id) MATCH SIMPLE
ON UPDATE NO ACTION ON DELETE NO ACTION DEFERRABLE INITIALLY DEFERRED
)
WITH (
OIDS=FALSE,
autovacuum_enabled=true,
autovacuum_vacuum_threshold=50,
autovacuum_vacuum_scale_factor=0.2,
autovacuum_analyze_threshold=50,
autovacuum_analyze_scale_factor=0.1,
autovacuum_vacuum_cost_delay=20,
autovacuum_vacuum_cost_limit=200,
autovacuum_freeze_min_age=50000000,
autovacuum_freeze_max_age=200000000,
autovacuum_freeze_table_age=150000000
);
ALTER TABLE my_table
OWNER TO postgres;
CREATE INDEX my_table_fk_id1
ON my_table
USING btree
(fk_id1 );
CREATE INDEX my_table_fk_id2
ON my_table
USING btree
(fk_id2 );
tables records count
select count(id) from my_table; --24061
select count(id) from my_table2; --24061
select count(id) from my_table3; --123
execution time
select * from my_table -- ~17sec
vacuum/analyze - no effect
description - length ~ 4000 chars in each row
postgres.conf - standart settings
Version: 9.1
select all fields except description reduce execution time to ~1,5 sec
How to icrease select speed with description ?
upd
--explain analyze select * from my_table
"Seq Scan on my_table (cost=0.00..3425.79 rows=24079 width=1015) (actual time=0.019..17.238 rows=24079 loops=1)"
"Total runtime: 18.649 ms"
The question is how to make this fast. The issue is not on the server since it takes 18ms there. The simple solution is to select fewer columns so that there is less to transfer over the network. My guess is that you have long descriptions on some. Leave that column off your select and try again.