Related
I have a table that is partitioned by hash on a column.
CREATE TABLE TEST(
ACCOUNT_NUMBER VARCHAR(20)
)
PARTITION BY HASH (ACCOUNT_NUMBER)
PARTITIONS 16
Now, I want to update the account_number column itself in the table because of certain requirements.
As this column is partitioned, I'm not able to issue an update command on the table like
Update test set account_number = new_value
as it results to the below error:
Error is: ORA-14402: UPDATING PARTITION WOULD CAUSE PARTITION CHANGE.
Row movement is set to disable for the table.
The one way I know is to enable row movement but I also want to explore other options.
Could you please advise me on how to solve this?
I have a question I know this was posted many times but I didn't find an answer to my problem. The problem is that I have a table and a column "id" I want it to be unique number just as normal. This type of column is serial and the next value after each insert is coming from a sequence so everything seems to be all right but it still sometimes shows this error. I don't know why. In the documentation, it says the sequence is foolproof and always works. If I add a UNIQUE constraint to that column will it help? I worked before many times on Postres but this error is showing for me for the first time. I did everything as normal and I never had this problem before. Can you help me to find the answer that can be used in the future for all tables that will be created? Let's say we have something easy like this:
CREATE TABLE comments
(
id serial NOT NULL,
some_column text NOT NULL,
CONSTRAINT id_pkey PRIMARY KEY (id)
)
WITH (
OIDS=FALSE
);
ALTER TABLE interesting.comments OWNER TO postgres;
If i add:
ALTER TABLE comments ADD CONSTRAINT id_id_key UNIQUE(id)
Will if be enough or is there some other thing that should be done?
This article explains that your sequence might be out of sync and that you have to manually bring it back in sync.
An excerpt from the article in case the URL changes:
If you get this message when trying to insert data into a PostgreSQL
database:
ERROR: duplicate key violates unique constraint
That likely means that the primary key sequence in the table you're
working with has somehow become out of sync, likely because of a mass
import process (or something along those lines). Call it a "bug by
design", but it seems that you have to manually reset the a primary
key index after restoring from a dump file. At any rate, to see if
your values are out of sync, run these two commands:
SELECT MAX(the_primary_key) FROM the_table;
SELECT nextval('the_primary_key_sequence');
If the first value is higher than the second value, your sequence is
out of sync. Back up your PG database (just in case), then run this command:
SELECT setval('the_primary_key_sequence', (SELECT MAX(the_primary_key) FROM the_table)+1);
That will set the sequence to the next available value that's higher
than any existing primary key in the sequence.
Intro
I also encountered this problem and the solution proposed by #adamo was basically the right solution. However, I had to invest a lot of time in the details, which is why I am now writing a new answer in order to save this time for others.
Case
My case was as follows: There was a table that was filled with data using an app. Now a new entry had to be inserted manually via SQL. After that the sequence was out of sync and no more records could be inserted via the app.
Solution
As mentioned in the answer from #adamo, the sequence must be synchronized manually. For this purpose the name of the sequence is needed. For Postgres, the name of the sequence can be determined with the command PG_GET_SERIAL_SEQUENCE. Most examples use lower case table names. In my case the tables were created by an ORM middleware (like Hibernate or Entity Framework Core etc.) and their names all started with a capital letter.
In an e-mail from 2004 (link) I got the right hint.
(Let's assume for all examples, that Foo is the table's name and Foo_id the related column.)
Command to get the sequence name:
SELECT PG_GET_SERIAL_SEQUENCE('"Foo"', 'Foo_id');
So, the table name must be in double quotes, surrounded by single quotes.
1. Validate, that the sequence is out-of-sync
SELECT CURRVAL(PG_GET_SERIAL_SEQUENCE('"Foo"', 'Foo_id')) AS "Current Value", MAX("Foo_id") AS "Max Value" FROM "Foo";
When the Current Value is less than Max Value, your sequence is out-of-sync.
2. Correction
SELECT SETVAL((SELECT PG_GET_SERIAL_SEQUENCE('"Foo"', 'Foo_id')), (SELECT (MAX("Foo_id") + 1) FROM "Foo"), FALSE);
Replace the table_name to your actual name of the table.
Gives the current last id for the table. Note it that for next step.
SELECT MAX(id) FROM table_name;
Get the next id sequence according to postgresql. Make sure this id is higher than the current max id we get from step 1
SELECT nextVal('"table_name_id_seq"');
if it's not higher than then use this step 3 to update the next sequence.
SELECT setval('"table_name_id_seq"', (SELECT MAX(id) FROM table_name)+1);
The primary key is already protecting you from inserting duplicate values, as you're experiencing when you get that error. Adding another unique constraint isn't necessary to do that.
The "duplicate key" error is telling you that the work was not done because it would produce a duplicate key, not that it discovered a duplicate key already commited to the table.
For future searchs, use ON CONFLICT DO NOTHING.
Referrence - https://www.calazan.com/how-to-reset-the-primary-key-sequence-in-postgresql-with-django/
I had the same problem try this:
python manage.py sqlsequencereset table_name
Eg:
python manage.py sqlsequencereset auth
you need to run this in production settings(if you have)
and you need Postgres installed to run this on the server
From http://www.postgresql.org/docs/current/interactive/datatype.html
Note: Prior to PostgreSQL 7.3, serial implied UNIQUE. This is no longer automatic. If you wish a serial column to be in a unique constraint or a primary key, it must now be specified, same as with any other data type.
In my case carate table script is:
CREATE TABLE public."Survey_symptom_binds"
(
id integer NOT NULL DEFAULT nextval('"Survey_symptom_binds_id_seq"'::regclass),
survey_id integer,
"order" smallint,
symptom_id integer,
CONSTRAINT "Survey_symptom_binds_pkey" PRIMARY KEY (id)
)
SO:
SELECT nextval('"Survey_symptom_binds_id_seq"'::regclass),
MAX(id)
FROM public."Survey_symptom_binds";
SELECT nextval('"Survey_symptom_binds_id_seq"'::regclass) less than MAX(id) !!!
Try to fix the proble:
SELECT setval('"Survey_symptom_binds_id_seq"', (SELECT MAX(id) FROM public."Survey_symptom_binds")+1);
Good Luck every one!
I had the same problem. It was because of the type of my relations. I had a table property which related to both states and cities. So, at first I had a relation from property to states as OneToOne, and the same for cities. And I had the same error "duplicate key violates unique constraint". That means that: I can only have one property related to one state and city. But that doesnt make sense, because a city can have multiple properties. So the problem is the relation. The relation should be ManyToOne. Many properties to One city
Table name started with a capital letter if tables were created by an ORM middleware (like Hibernate or Entity Framework Core etc.)
SELECT setval('"Table_name_Id_seq"', (SELECT MAX("Id") FROM "Table_name") + 1)
WHERE
NOT EXISTS (
SELECT *
FROM (SELECT CURRVAL(PG_GET_SERIAL_SEQUENCE('"Table_name"', 'Id')) AS seq, MAX("Id") AS max_id
FROM "Table_name") AS seq_table
WHERE seq > max_id
)
try that CLI
it's just a suggestion to enhance the adamo code (thanks a lot adamo)
SELECT setval('tableName_columnName_seq', (SELECT MAX(columnName) FROM tableName));
For programatically solution at Django. Based on Paolo Melchiorre's answer, I wrote a chunk as a function to be called before any .save()
from django.db import connection
def setSqlCursor(db_table):
sql = """SELECT pg_catalog.setval(pg_get_serial_sequence('"""+db_table+"""', 'id'), MAX(id)) FROM """+db_table+""";"""
with connection.cursor() as cursor:
cursor.execute(sql)
I have similar problem but I solved it by removing all the foreign key in my Postgresql
Recently I saw a strange scenario with my PostgreSQL DB. The information schema of my database is showing a different sequence name than the one actually allocated for the column of my table.
The issue is:
I have a table tab_1
id name
1 emp1
2 emp2
3 emp3
Previously the id column (integer) of the table was an auto generated field where the sequence number was generated at run time via JPA. (Sequence name: tab_1_seq)
We made a change and updated the table's column id to bigserial and the sequence is maintained in the column level (allocated new sequence: tab_1_temp_seq) not handled by the JPA anymore.
After this change everything was working fine for few months and after that we faced an error - "the sequence "tab_1_temp_seq" is not yet defined in this session"
On analyzing the issue I found out that there is a mismatch between the sequences allocated for the table.
In the table structure, we where shown the sequence as tab_1_temp_seq and in the information_schema the table was allocated with the old sequence - tab_1_seq.
I am not sure what has really triggered this to happen, as we are not managing our database system. If you have faced any issues like this, kindly let me know its root cause.
Queries:
SELECT table_name, column_name, column_default from information_schema.columns where table_name = ‘tab_1’;
result :
table_name column_name column_default
tab_1 id nextval('tab_1_seq::regclass')
Below are the details found in the table structure/properties:
id nextval('tab_1_temp_seq::regclass')
name varChar
Perhaps you are suffering from data corruption, but it is most likely that you are suffering from bad tools to visualize your database objects. Whatever program shows you the “table structure/properties” might be confused.
To find out the truth (which DEFAULT value PostgreSQL uses), run:
SELECT pg_get_expr(adbin, adrelid)
FROM pg_attrdef
WHERE adrelid = 'tab1'::regclass;
This is also what information_schema.columns will show, but I added the naked query for clarity.
This DEFAULT value will be used whenever the INSERT statement either doesn't specify the id column or fills it with the special value DEFAULT.
Perhaps the confusion is also caused by different programs that may set default values in their way. The way I showed above is PostgreSQL's way, but nothing can keep a third-party tool from using its own sequence to filling the id.
I have a question I know this was posted many times but I didn't find an answer to my problem. The problem is that I have a table and a column "id" I want it to be unique number just as normal. This type of column is serial and the next value after each insert is coming from a sequence so everything seems to be all right but it still sometimes shows this error. I don't know why. In the documentation, it says the sequence is foolproof and always works. If I add a UNIQUE constraint to that column will it help? I worked before many times on Postres but this error is showing for me for the first time. I did everything as normal and I never had this problem before. Can you help me to find the answer that can be used in the future for all tables that will be created? Let's say we have something easy like this:
CREATE TABLE comments
(
id serial NOT NULL,
some_column text NOT NULL,
CONSTRAINT id_pkey PRIMARY KEY (id)
)
WITH (
OIDS=FALSE
);
ALTER TABLE interesting.comments OWNER TO postgres;
If i add:
ALTER TABLE comments ADD CONSTRAINT id_id_key UNIQUE(id)
Will if be enough or is there some other thing that should be done?
This article explains that your sequence might be out of sync and that you have to manually bring it back in sync.
An excerpt from the article in case the URL changes:
If you get this message when trying to insert data into a PostgreSQL
database:
ERROR: duplicate key violates unique constraint
That likely means that the primary key sequence in the table you're
working with has somehow become out of sync, likely because of a mass
import process (or something along those lines). Call it a "bug by
design", but it seems that you have to manually reset the a primary
key index after restoring from a dump file. At any rate, to see if
your values are out of sync, run these two commands:
SELECT MAX(the_primary_key) FROM the_table;
SELECT nextval('the_primary_key_sequence');
If the first value is higher than the second value, your sequence is
out of sync. Back up your PG database (just in case), then run this command:
SELECT setval('the_primary_key_sequence', (SELECT MAX(the_primary_key) FROM the_table)+1);
That will set the sequence to the next available value that's higher
than any existing primary key in the sequence.
Intro
I also encountered this problem and the solution proposed by #adamo was basically the right solution. However, I had to invest a lot of time in the details, which is why I am now writing a new answer in order to save this time for others.
Case
My case was as follows: There was a table that was filled with data using an app. Now a new entry had to be inserted manually via SQL. After that the sequence was out of sync and no more records could be inserted via the app.
Solution
As mentioned in the answer from #adamo, the sequence must be synchronized manually. For this purpose the name of the sequence is needed. For Postgres, the name of the sequence can be determined with the command PG_GET_SERIAL_SEQUENCE. Most examples use lower case table names. In my case the tables were created by an ORM middleware (like Hibernate or Entity Framework Core etc.) and their names all started with a capital letter.
In an e-mail from 2004 (link) I got the right hint.
(Let's assume for all examples, that Foo is the table's name and Foo_id the related column.)
Command to get the sequence name:
SELECT PG_GET_SERIAL_SEQUENCE('"Foo"', 'Foo_id');
So, the table name must be in double quotes, surrounded by single quotes.
1. Validate, that the sequence is out-of-sync
SELECT CURRVAL(PG_GET_SERIAL_SEQUENCE('"Foo"', 'Foo_id')) AS "Current Value", MAX("Foo_id") AS "Max Value" FROM "Foo";
When the Current Value is less than Max Value, your sequence is out-of-sync.
2. Correction
SELECT SETVAL((SELECT PG_GET_SERIAL_SEQUENCE('"Foo"', 'Foo_id')), (SELECT (MAX("Foo_id") + 1) FROM "Foo"), FALSE);
Replace the table_name to your actual name of the table.
Gives the current last id for the table. Note it that for next step.
SELECT MAX(id) FROM table_name;
Get the next id sequence according to postgresql. Make sure this id is higher than the current max id we get from step 1
SELECT nextVal('"table_name_id_seq"');
if it's not higher than then use this step 3 to update the next sequence.
SELECT setval('"table_name_id_seq"', (SELECT MAX(id) FROM table_name)+1);
The primary key is already protecting you from inserting duplicate values, as you're experiencing when you get that error. Adding another unique constraint isn't necessary to do that.
The "duplicate key" error is telling you that the work was not done because it would produce a duplicate key, not that it discovered a duplicate key already commited to the table.
For future searchs, use ON CONFLICT DO NOTHING.
Referrence - https://www.calazan.com/how-to-reset-the-primary-key-sequence-in-postgresql-with-django/
I had the same problem try this:
python manage.py sqlsequencereset table_name
Eg:
python manage.py sqlsequencereset auth
you need to run this in production settings(if you have)
and you need Postgres installed to run this on the server
From http://www.postgresql.org/docs/current/interactive/datatype.html
Note: Prior to PostgreSQL 7.3, serial implied UNIQUE. This is no longer automatic. If you wish a serial column to be in a unique constraint or a primary key, it must now be specified, same as with any other data type.
In my case carate table script is:
CREATE TABLE public."Survey_symptom_binds"
(
id integer NOT NULL DEFAULT nextval('"Survey_symptom_binds_id_seq"'::regclass),
survey_id integer,
"order" smallint,
symptom_id integer,
CONSTRAINT "Survey_symptom_binds_pkey" PRIMARY KEY (id)
)
SO:
SELECT nextval('"Survey_symptom_binds_id_seq"'::regclass),
MAX(id)
FROM public."Survey_symptom_binds";
SELECT nextval('"Survey_symptom_binds_id_seq"'::regclass) less than MAX(id) !!!
Try to fix the proble:
SELECT setval('"Survey_symptom_binds_id_seq"', (SELECT MAX(id) FROM public."Survey_symptom_binds")+1);
Good Luck every one!
I had the same problem. It was because of the type of my relations. I had a table property which related to both states and cities. So, at first I had a relation from property to states as OneToOne, and the same for cities. And I had the same error "duplicate key violates unique constraint". That means that: I can only have one property related to one state and city. But that doesnt make sense, because a city can have multiple properties. So the problem is the relation. The relation should be ManyToOne. Many properties to One city
Table name started with a capital letter if tables were created by an ORM middleware (like Hibernate or Entity Framework Core etc.)
SELECT setval('"Table_name_Id_seq"', (SELECT MAX("Id") FROM "Table_name") + 1)
WHERE
NOT EXISTS (
SELECT *
FROM (SELECT CURRVAL(PG_GET_SERIAL_SEQUENCE('"Table_name"', 'Id')) AS seq, MAX("Id") AS max_id
FROM "Table_name") AS seq_table
WHERE seq > max_id
)
try that CLI
it's just a suggestion to enhance the adamo code (thanks a lot adamo)
SELECT setval('tableName_columnName_seq', (SELECT MAX(columnName) FROM tableName));
For programatically solution at Django. Based on Paolo Melchiorre's answer, I wrote a chunk as a function to be called before any .save()
from django.db import connection
def setSqlCursor(db_table):
sql = """SELECT pg_catalog.setval(pg_get_serial_sequence('"""+db_table+"""', 'id'), MAX(id)) FROM """+db_table+""";"""
with connection.cursor() as cursor:
cursor.execute(sql)
I have similar problem but I solved it by removing all the foreign key in my Postgresql
I set up a set of partitioned tables per the docs at http://www.postgresql.org/docs/8.1/interactive/ddl-partitioning.html
CREATE TABLE t (year, a);
CREATE TABLE t_1980 ( CHECK (year = 1980) ) INHERITS (t);
CREATE TABLE t_1981 ( CHECK (year = 1981) ) INHERITS (t);
CREATE RULE t_ins_1980 AS ON INSERT TO t WHERE (year = 1980)
DO INSTEAD INSERT INTO t_1980 VALUES (NEW.year, NEW.a);
CREATE RULE t_ins_1981 AS ON INSERT TO t WHERE (year = 1981)
DO INSTEAD INSERT INTO t_1981 VALUES (NEW.year, NEW.a);
From my understanding, if I INSERT INTO t (year, a) VALUES (1980, 5), it will go to t_1980, and if I INSERT INTO t (year, a) VALUES (1981, 3), it will go to t_1981. But, my understanding seems to be incorrect. First, I can't understand the following from the docs
"There is currently no simple way to specify that rows must not be inserted into the master table. A CHECK (false) constraint on the master table would be inherited by all child tables, so that cannot be used for this purpose. One possibility is to set up an ON INSERT trigger on the master table that always raises an error. (Alternatively, such a trigger could be used to redirect the data into the proper child table, instead of using a set of rules as suggested above.)"
Does the above mean that in spite of setting up the CHECK constraints and the RULEs, I also have to create TRIGGERs on the master table so that the INSERTs go to the correct tables? If that were the case, what would be the point of the db supporting partitioning? I could just set up the separate tables myself? I inserted a bunch of values into the master table, and those rows are still in the master table, not in the inherited tables.
Second question. When retrieving the rows, do I select from the master table, or do I have to select from the individual tables as needed? How would the following work?
SELECT year, a FROM t WHERE year IN (1980, 1981);
Update: Seems like I have found the answer to my own question
"Be aware that the COPY command ignores rules. If you are using COPY to insert data, you must copy the data into the correct child table rather than into the parent. COPY does fire triggers, so you can use it normally if you create partitioned tables using the trigger approach."
I was indeed using COPY FROM to load data, so RULEs were being ignored. Will try with TRIGGERs.
Definitely try triggers.
If you think you want to implement a rule, don't (the only exception that comes to mind is updatable views). See this great article by depesz for more explanation there.
In reality, Postgres only supports partitioning on the reading side of things. You're going to have setup the method of insertition into partitions yourself - in most cases TRIGGERing. Depending on the needs and applicaitons, it can sometimes be faster to teach your application to insert directly into the partitions.
When selecting from partioned tables, you can indeed just SELECT ... WHERE... on the master table so long as your CHECK constraints are properly setup (they are in your example) and the constraint_exclusion parameter is set corectly.
For 8.4:
SET constraint_exclusion = partition;
For < 8.4:
SET constraint_exclusion = on;
All this being said, I actually really like the way Postgres does it and use it myself often.
Does the above mean that in spite of
setting up the CHECK constraints and
the RULEs, I also have to create
TRIGGERs on the master table so that
the INSERTs go to the correct tables?
Yes. Read point 5 (section 5.9.2)
If that were the case, what would be
the point of the db supporting
partitioning? I could just set up the
separate tables myself?
Basically: the INSERTS in the child tables must be done explicitly (either creating TRIGGERS, or by specifying the correct child table in the query). But the partitioning
is transparent for SELECTS, and (given the storage and indexing advantages of this schema) that's the point.
(Besides, because the partitioned tables are inherited,
the schema is inherited from the parent, hence consistency
is enforced).
Triggers are definitelly better than rules.
Today I've played with partitioning of materialized view table and run into problem with triggers solution.
Why ?
I'm using RETURNING and current solution returns NULL :)
But here's solution which works for me - correct me if I'm wrong.
1. I have 3 tables which are inserted with some data, there's an view (let we call it viewfoo) which contains
data which need to be materialized.
2. Insert into last table have trigger which inserts into materialized view table
via INSERT INTO matviewtable SELECT * FROM viewfoo WHERE recno=NEW.recno;
That works fine and I'm using RETURNING recno; (recno is SERIAL type - sequence).
Materialized view (table) need to be partitioned because it's huge, and
according to my tests it's at least x10 faster for SELECT in this case.
Problems with partitioning:
* Current trigger solution RETURN NULL - so I cannot use RETURNING recno.
(Current trigger solution = trigger explained at depesz page).
Solution:
I've changed trigger of my 3rd table TO NOT insert into materialized view table (that table is parent of partitioned tables), but created new trigger which inserts
partitioned table directly FROM 3rd table and that trigger RETURN NEW.
Materialized view table is automagically updated and RETURNING recno works fine.
I'll be glad if this helped to anybody.