When I execute a file containing SQL commands with psql -f, I get output like this (truncated):
CREATE DOMAIN
CREATE TABLE
CREATE TABLE
INSERT 0 1
INSERT 0 1
INSERT 0 1
What do the numbers 0 and 1 mean? (I think 1 is the number of rows modified. But 0?) I can't find it in PostgreSQL's official documentation or anywhere else.
This is documented with the INSERT command
On successful completion, an INSERT command returns a command tag of the form
INSERT oid count
The count is the number of rows inserted or updated. oid is always 0 (it used to be the OID assigned to the inserted row if count was exactly one and the target table was declared WITH OIDS and 0 otherwise, but creating a table WITH OIDS is not supported anymore).
Related
I am loading table with 41 millions of files from sql dump to table.
PostgreSQL Server 14.3 is setuped with best practice from google (workmem, jobs etc).
Table have a lot of index. After loading of dump I have seen in cmd next:
...
INSERT 0 250
INSERT 0 250
INSERT 0 141
setval
----------
41349316
ALTER TABLE
ALTER TABLE
CREATE INDEX
CREATE INDEX
CREATE INDEX
CREATE INDEX
CREATE INDEX
CREATE INDEX
And by output it continue to do something. Process in CMD is not finished. No new line just as I had show.
I checked current activity with:
select * from pg_stat_activity where datname = 'dbname';
It show idle for column state google says that it show last command that was run in session. I checked after few hours and nothing is changed.
pg_stat_progress_create_index do not show nothing.
So I do not know what to do. Could indexing process is hanged? Or all fine and I should to wait? If yes what it's doing now? What I can\should to do?
UPD from next morning: Today I rechecked all
SELECT * FROM pg_stat_progress_create_index;
is still do not show nothing.
Console window did two new prints:
CREATE INDEX
CREATE INDEX
I again checked:
select * from pg_stat_activity where datname = 'dbname';
it show that active process is:
CREATE INDEX index_insert_status ON public.xml_files USING btree (insert_status);
But why pg_stat_progress_create_index do not show nothing??
I'm using LOAD command to get data into a table where one of the columns has the default value of the current timestamp. I had NULL value in the data being read as I thought it would cause the table to use the default value but based on above error that's not the case. How do I avoid the above error in this case?
Here is the full command, input file is text file: LOAD FROM ${LOADDIR}/${InputFile}.exp OF DEL MODIFIED BY COLDEL| INSERT INTO TEMP_TABLE NONRECOVERABLE
Try:
LOAD FROM ${LOADDIR}/${InputFile}.exp OF DEL MODIFIED BY USEDEFAULTS COLDEL| INSERT INTO TEMP_TABLE NONRECOVERABLE
This modifier usedefaults has been available in Db2-LUW since V7.x, as long as they are fully serviced (i.e. have had the final fixpack correctly applied).
Note that some Db2-LUW versions place restrictions on usage of usedefaults modifier, as detailed in the documentation. For example, restrictions relating to use with other modifiers, or modes or target table type.
Always specify your Db2-server version and platform when asking for help because the answer can depende on these facts.
You can specify which columns from the input file go into which columns of the table using METHOD P - if you omit the column you want the default for it will throw a warning but the default will be populated:
$ db2 "create table testtab1 (cola int, colb int, colc timestamp not null default)"
DB20000I The SQL command completed successfully.
$ cat tt1.del
1,1,1
2,2,2
3,3,99
$ db2 "load from tt1.del of del method P(1,2) insert into testtab1 (cola, colb)"
SQL27967W The COPY NO recoverability parameter of the Load has been converted
to NONRECOVERABLE within the HADR environment.
SQL3109N The utility is beginning to load data from file
"/home/db2inst1/tt1.del".
SQL3500W The utility is beginning the "LOAD" phase at time "07/12/2021
10:14:04.362385".
SQL3112W There are fewer input file columns specified than database columns.
SQL3519W Begin Load Consistency Point. Input record count = "0".
SQL3520W Load Consistency Point was successful.
SQL3110N The utility has completed processing. "3" rows were read from the
input file.
SQL3519W Begin Load Consistency Point. Input record count = "3".
SQL3520W Load Consistency Point was successful.
SQL3515W The utility has finished the "LOAD" phase at time "07/12/2021
10:14:04.496670".
Number of rows read = 3
Number of rows skipped = 0
Number of rows loaded = 3
Number of rows rejected = 0
Number of rows deleted = 0
Number of rows committed = 3
$ db2 "select * from testtab1"
COLA COLB COLC
----------- ----------- --------------------------
1 1 2021-12-07-10.14.04.244232
2 2 2021-12-07-10.14.04.244232
3 3 2021-12-07-10.14.04.244232
3 record(s) selected.
I followed the steps as outlined in this tutorial to use pg_prewarm extention for pre-warming the buffer cache in PostgreSQL:
https://ismailyenigul.medium.com/pg-prewarm-extention-to-pre-warming-the-buffer-cache-in-postgresql-7e033b9a386d
The first time I ran it, I got 1 as the result:
mydb=> SELECT pg_prewarm('useraccount');
pg_prewarm
------------
1
After that I had to drop the table and recreate it. Since then, when I run the same command, I get 0 as the result always. I am not sure if that's expected or if I am missing something?
mydb=> SELECT pg_prewarm('useraccount');
pg_prewarm
------------
0
The function comment in contrib/pg_prewarm/pg_prewarm.c says:
* [...] The
* return value is the number of blocks successfully prewarmed.
So the first time, there was 1 block in the table. After dropping and re-creating the table, it is empty, so 0 blocks are cached.
I am migrating from mssql to postgresql
I am trying to assign a value to a temporary variable in select query
Below is the query in mssql
select flag = 0
It gives 0 as output wit flag as column identifier in mssql
I tried the following in postgresql
select flag := 0
select flag [:=0]
It says syntax error at or near :=
Does anybody know where I am going wrong?
It gives 0 as output wit flag as column identifier in mssql
Postgres honors the SQL standard and a column alias is defined with the AS keyword there.
So to get a column named flag with the value zero use the following:
select 0 as flag
flag = 0 in standard SQL (and Postgres) is a boolean expression that compares the the column flag with the value zero and returns either true, false or null depending on the column's value.
I want to see how many rows my delete query effects so I know its correct.
Is this possible using pgadmin?
Start a transaction, delete and then rollback;
In psql :
test1=> begin;
BEGIN
test1=> delete from test1 where test1_id = 1;
DELETE 2
test1=> rollback;
ROLLBACK
In pgAdmin (in the "History" tab on the "Output pane"):
-- Executing query:
begin;
Query returned successfully with no result in 16 ms.
-- Executing query:
delete from test1 where test1_id = 1;
Query returned successfully: 2 rows affected, 16 ms execution time.
-- Executing query:
rollback;
Query returned successfully with no result in 16 ms.
I'm not sure how to automatically do this but you can always do a select then a delete.
SELECT COUNT(*) FROM foo WHERE delete_me=true;
DELETE FROM foo WHERE delete_me=true;
As Andrew said, when doing interactive administration, you can just replace DELETE by SELECT COUNT(*).
If you want to this information in a program of yours (after executing the DELETE), many programming languages provide a construct for this. For example, in PHP it's pg_affected_rows and in .NET it's the return value of ExecuteNonQuery.
Use RETURNING and fetch the result like you would fetch a SELECT-result:
DELETE FROM test1 WHERE test1_id = 1 RETURNING id;
This works as of version 8.2