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Postgres Reading Files

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I’m working on items for migrating my database class from Oracle to PostgreSQL. I ran into an interesting limitation when I tried using the COPY command to read an external CSV file.

I had prepared the system by creating a new directory hierarchy owned by the postgres user on top of a /u01/app mount point. I set the ownership of the directories and files with the following command from the /u01/app mount point:

chown -R postgres:postgres postgres

After running the following command:

COPY transaction_upload
FROM '/u01/app/upload/postgres/transaction_upload_postgres.csv' DELIMITERS ',' CSV;

The command raised the following error:

COPY transaction_upload FROM '/u01/app/upload/postgres/transaction_upload_postgres.csv' DELIMITERS ',' CSV;
ERROR:  must be superuser or a member of the <code>pg_read_server_files</code> role to COPY from a file
HINT:  Anyone can COPY to stdout or from stdin. psql's \copy command also works for anyone.

The two options for fixing the problem are: Changing the student user to a superuser, and granting the pg_read_server_files role to the student user. Changing the student user to a superuser isn’t really a practical option. So, I connected as the postgres superuser and granted the pg_read_server_files role to the student user. It is a system level role and therefore doesn’t limit the role to only the videodb database.

As the postgres user, type the following command to grant the pg_read_server_files role to the system user:

GRANT pg_read_server_files TO student;

After granting the role to the student user, I created a small test case. The test table definition is:

CREATE TABLE test
( id          INTEGER
, first_name  VARCHAR(20)
, last_name   VARCHAR(20));

I created a test.csv file in the /u01/app/upload/postgres directory, like:

1,Simon,Bolivar
2,Peter,Davenport
3,Michael,Swan

The test.csv file requires the following permissions and ownerships:

-rw-r--r--. 1 postgres postgres 49 Nov 13 10:56 test.csv

The permissions are user read-write, groups read, and others read. The ownership should be granted to postgres and the primary group for the postgres user, which should also be postgres.

You can then connect to psql as the student user with the database set to videodb and run the following copy command:

COPY test
FROM '/u01/app/upload/postgres/test.csv' DELIMITERS ',' CSV;

If you put a comma at the end of each line, like you would do in MySQL, it raises an error. The trailing comma raises the following error:

ERROR:  extra data after last expected column

If you forget a delimiting commas somewhere on a line, the copy command raises the following error:

ERROR:  missing data for column "last_name"
CONTEXT:  COPY tester, line 3: "3,Michael Swan"

The error points to the column after the missing column. The context points to the line number while displaying the text.

You should take careful note that the copy command is an appending command. If you run it a second time, you insert a duplicate set of values in the target table.

After experimenting, its time to fix my student instance. The transaction_upload_mysql.csv file has two critical errors that need to be fixed. They are:

  1. A comma terminates each line, which would raise an extra data after last expected column error.
  2. A comma terminates each line followed by some indefinite amount of whitespace, which would also raise an extra data after last expected column error.

Since I have students with little expertise in Unix or Linux commands, I must provide a single command that they can use to convert the file with problems to one without problems. However, they should copy the transaction_upload_mysql.csv file to ensure they don’t disable the equivalent functionality for the MySQL solution space.

They should copy two files as the root user from the mysql directory to the postgres directory, as follows:

cp /u01/app/mysql/upload/transaction_upload_mysql.csv /u01/app/postgres/upload/transaction_upload_postgres.csv
cp /u01/app/mysql/upload/transaction_upload2_mysql.csv /u01/app/postgres/upload/transaction_upload2_postgres.csv

As the root user in the /u01/app/upload/postgres directory, run the following command:

cat transaction_upload_postgres.csv | sed -e 's/\,$//g' > x; cat x | sed -e 's/\,[[:space:]]*$//g' > y; mv y transaction_upload_postgres.csv; rm x

Please check the file permissions and ownerships with the ll (long list) command. If the file isn’t like this:

-rw-r--r--. 1 postgres postgres 49 Nov 13 10:56 transaction_upload_postgres.csv

Then, they should be able to change it as the root user with these commands:

chown postgres:postgres transaction_upload_postgres.csv
chmod 544 transaction_upload_postgres.csv

Lastly, they should connect to the psql as the student user, using the videodb database and run the following command:

COPY transaction_upload
FROM '/u01/app/postgres/upload/transaction_upload_postgres.csv' DELIMITERS ',' CSV;

A query of the import table with this:

SELECT COUNT(*) FROM transaction_upload;

should return:

 count 
-------
 11520
(1 row)

As always, I hope this helps those looking for some explanation and example on the copy feature of PostgreSQL.

Written by maclochlainn

November 13th, 2019 at 7:38 am

Posted in Fedora,Linux,Postgres,PostgreSQL

Tagged with ,

PostgreSQL and LPAD

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While porting my Oracle code to PostgreSQL I encountered a little quirk. It’s probably not a quirk except for the fact that I’ve worked in Oracle so long. Oracle implicitly type casts so well that we seldom notice.

PostreSQL doesn’t work like Oracle. It does type cast sometimes but not very often. I tried porting the following segment from my Oracle stored procedure to PostgreSQL:

/* Add account number with zeros. */
FOR j IN 1..50 LOOP
  INSERT INTO account_list
  VALUES
  ( lv_airport_code||'-'||LPAD(j,6,'0')
  , NULL
  , NULL
  , 1002
  , 1002 );
END LOOP;

Oracle implicitly casts the integer j to a text string before running the LPAD function. In PostgreSQL, it doesn’t cast the integer to a text string before calling the LPAD function. Since the LPAD function is not overloaded, calling it with an integer, integer, and text set of parameters fails at runtime but the code doesn’t raise an exception when compiling it as a stored procedure.

At runtime, it raises the following error:

ERROR:  invalid INPUT syntax FOR INTEGER: "function lpad(integer, integer, unknown) does not exist"
CONTEXT:  PL/pgSQL FUNCTION seed_account_list() line 48 at assignment

You can fix the code by explicitly casting the LPAD function’s first parameter to a text string. You do that as follows below:

/* Add account number with zeros. */
FOR j IN 1..50 LOOP
  INSERT INTO account_list
  VALUES
  ( lv_airport_code||'-'||LPAD(j::text,6,'0')
  , NULL
  , NULL
  , 1002
  , 1002 );
END LOOP;

This fixes the casting problem. As always, I hope this helps those looking for a solution.

Written by maclochlainn

November 12th, 2019 at 4:08 pm

Posted in Fedora,Linux,PL/pgSQL,Postgres,PostgreSQL,sql

Tagged with ,

Postgres Foreign Keys

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Just sorting out how to query the information_schema to discover the magic for a query of a table’s foreign key constraints. This query works to return the foreign key constraints:

SELECT   conrelid::regclass::text AS table_from
,        conname AS foreign_key
,        pg_get_constraintdef(oid)
FROM     pg_constraint
WHERE    contype = 'f'
AND      connamespace = 'public'::regnamespace 
AND      conrelid::regclass::text = 'rental_item'
ORDER BY conrelid::regclass::text
,        conname;

It returns the following for the rental_item table:

 table_from  |   foreign_key    |                           pg_get_constraintdef                            
-------------+------------------+---------------------------------------------------------------------------
 rental_item | fk_rental_item_1 | FOREIGN KEY (rental_id) REFERENCES rental(rental_id)
 rental_item | fk_rental_item_2 | FOREIGN KEY (item_id) REFERENCES item(item_id)
 rental_item | fk_rental_item_3 | FOREIGN KEY (created_by) REFERENCES system_user(system_user_id)
 rental_item | fk_rental_item_4 | FOREIGN KEY (last_updated_by) REFERENCES system_user(system_user_id)
 rental_item | fk_rental_item_5 | FOREIGN KEY (rental_item_type) REFERENCES common_lookup(common_lookup_id)
(5 rows)

As always, I post these tidbit for others to discover and use with less pain.

Written by maclochlainn

November 6th, 2019 at 12:31 am

Posted in Database Design,DBA,Linux,psql,sql

Tagged with ,

Postgres Overloaded Routines

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Earlier I showed how to write an anonymous block in PostgreSQL PL/pgSQL to drop routines, like functions and procedures. However, it would only work when they’re not overloaded functions or procedures. The following lets you drop all routines, including overloaded functions and procedures. Overloaded procedures are those that share the same name but have different parameter lists.

Before you can test the anonymous block, you need to create a set of overloaded functions or procedures. You can create a set of overloaded hello procedures with the following syntax:

CREATE FUNCTION hello()
RETURNS text AS
$$
DECLARE
  output  VARCHAR;
BEGIN
  SELECT 'Hello World!' INTO output;
  RETURN output;
END
$$ LANGUAGE plpgsql;
 
CREATE FUNCTION hello(whom text)
RETURNS text AS
$$
DECLARE
  output  VARCHAR;
BEGIN
  SELECT CONCAT('Hello ',whom,'!') INTO output;
  RETURN output;
END
$$ LANGUAGE plpgsql;
 
CREATE FUNCTION hello(id int, whom text)
RETURNS text AS
$$
DECLARE
  output  VARCHAR;
BEGIN
  SELECT CONCAT('[',id,'] Hello ',whom,'!') INTO output;
  RETURN output;
END
$$ LANGUAGE plpgsql;

You can test the overloaded hello function, like so from the videodb schema:

videodb=> SELECT hello();
    hello     
--------------
 Hello World!
(1 ROW)
 
videodb=> SELECT hello('Captain Marvel');
         hello         
-----------------------
 Hello Captain Marvel!
(1 ROW)
 
videodb=> SELECT hello(1,'Captain America');
           hello            
----------------------------
 [1] Hello Captain America!
(1 ROW)

Then, you can query the information_schema to verify that you’ve created a set of overloaded procedures with the following query:

SELECT   proc.specific_schema AS procedure_schema
,        proc.specific_name
,        proc.routine_name AS procedure_name
,        proc.external_language
,        args.parameter_name
,        args.parameter_mode
,        args.data_type
FROM     information_schema.routines proc left join information_schema.parameters args
ON       proc.specific_schema = args.specific_schema
AND      proc.specific_name = args.specific_name
WHERE    proc.routine_schema NOT IN ('pg_catalog', 'information_schema')
AND      proc.routine_type IN ('FUNCTION','PROCEDURE')
ORDER BY procedure_schema
,        specific_name
,        procedure_name
,        args.ordinal_position;

It should return the following:

 procedure_schema | specific_name | procedure_name | external_language | parameter_name | parameter_mode | data_type 
------------------+---------------+----------------+-------------------+----------------+----------------+-----------
 public           | hello_35451   | hello          | PLPGSQL           |                |                | 
 public           | hello_35452   | hello          | PLPGSQL           | whom           | IN             | text
 public           | hello_35453   | hello          | PLPGSQL           | id             | IN             | integer
 public           | hello_35453   | hello          | PLPGSQL           | whom           | IN             | text
(4 rows)

The set session command maps the videodb catalog for the following anonymous block program.

SET SESSION "videodb.catalog_name" = 'videodb';

The following anonymous block lets you get rid of any ordinary or overloaded function and procedure:

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DO $$
DECLARE
  /* Declare an indefinite length string for SQL statement. */
  sql  VARCHAR;
 
  /* Declare variables to manage cursor return values. */
  row  RECORD;
  arg  VARCHAR;
 
  /* Declare parameter list. */
  list VARCHAR;
 
  /* Declare a routine cursor. */
  routine_cursor CURSOR FOR
    SELECT routine_name
    ,      specific_name
    ,      routine_type
    FROM   information_schema.routines
    WHERE  specific_catalog = current_setting('videodb.catalog_name')
    AND    routine_schema = 'public';
 
  /* Declare a parameter cursor. */
  parameter_cursor CURSOR (cv_specific_name varchar) FOR
    SELECT args.data_type
    FROM   information_schema.parameters args
    WHERE  args.specific_schema = 'public'
    AND    args.specific_name = cv_specific_name;
 
BEGIN
  /* Open the cursor. */
  OPEN routine_cursor;
  <<row_loop>>
  LOOP
    /* Fetch table names. */
    FETCH routine_cursor INTO row;
 
    /* Exit when no more records are found. */
    EXIT row_loop WHEN NOT FOUND;
 
    /* Initialize parameter list. */
    list := '(';
 
    /* Open the parameter cursor. */
    OPEN parameter_cursor(row.specific_name::varchar);
    <<parameter_loop>>
    LOOP
      FETCH parameter_cursor INTO arg;
 
      /* Exit the parameter loop. */
      EXIT parameter_loop WHEN NOT FOUND;
 
      /* Add parameter and delimit more than one parameter with a comma. */
      IF LENGTH(list) > 1 THEN
        list := CONCAT(list,',',arg);
      ELSE
        list := CONCAT(list,arg);
      END IF;
    END LOOP;
 
    /* Close the parameter list. */
    list := CONCAT(list,')');
 
    /* Close the parameter cursor. */
    CLOSE parameter_cursor;
 
    /* Concatenate together a DDL to drop the table with prejudice. */
    sql := 'DROP '||row.routine_type||' IF EXISTS '||row.routine_name||list;
 
    /* Execute the DDL statement. */
    EXECUTE sql;
  END LOOP;
 
  /* Close the routine_cursor. */
  CLOSE routine_cursor;
END;
$$;

Now, you possess the magic to automate cleaning up your schema when you combine this with my earlier post on dynamically dropping tables, sequences, and triggers.

Written by maclochlainn

November 5th, 2019 at 12:11 am

Posted in Fedora,Linux,Postgres,PostgreSQL,sql,Stored Procedures

Tagged with , , ,

DBeaver for PostgreSQL

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I’m migrating my database classes from the Oracle database to the PostgreSQL database. Using the Oracle Express Edition has always required a virtualized image because students use Windows and Mac OS. Also, the university doesn’t like my use of a virtualized image. Virtualization imposes incremental cost on students to have high end laptops.

The available Docker images don’t typically support the Oracle Express Edition. That means there are licensing implications tied to Oracle.

As a committee, we decided to use PostgreSQL as our new database platform. We opted to use PostgreSQL over MySQL because it supports arrays and stored procedures. PostgreSQL PL/pgSQL are a solid implementation of stored procedures. While MySQL supports a stored procedure language, it effectively discourages using it.

We use sqlplus, mysql, or psql Command-Line Interface (CLI) as the primary interface. That’s because CLI supports production-oriented deployment and DevOps practices. The Open Source DBeaver project provides a clean native GUI management console for PostgreSQL. DBeaver also supports other databases, which pgAdmin doesn’t.

You click the Download button from the DBeaver home page. It support Windows, Mac OS, and Linux distributions. I downloaded the Linux RPM package to my Downloads directory. You can run the RPM with the following syntax:

rpm -ivh dbeaver-ce-6.2.3-stable.x86_64.rpm

It doesn’t check for dependencies. The installation is quick. You can verify that it’s installed with the following command:

which dbeaver

It installs here:

/usr/bin/dbeaver

If you failed to install the PostgreSQL JAR file, you’ll see the following error message:

It will look like the following on Linux:

You should have a user in the pg_hba.conf file, like the following:

host    all             all             127.0.0.1/32            trust

As always, I hope this helps those solving problems.

Written by maclochlainn

November 3rd, 2019 at 5:06 pm

Posted in Fedora,Java,Linux,Mac OS X,PL/pgSQL,Postgres,PostgreSQL,psql,sql,SQL*Plus,Unix

Tagged with ,

Java and Postgres

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I wanted to get Java working with PostgreSQL to test some GUI interfaces on Linux. Figuring out the necessary JAR file for the JDBC was my first hurdle. I found it was postgreSQL-42-2.5.jar file.

You can download it with the following command line:

wget https://jdbc.postgresql.org/download/postgresql-42.2.5.jar

I downloaded it to a Java directory off the home/student directory. Then, I added the following CLASSPATH to local java.env environment file.

#!/usr/bin/bash
 
# Set the Java CLASSPATH environment variable to include the JDBC jar file.
export set CLASSPATH=/home/student/Java/postgresql-42.2.5.jar:.

I sourced the postgresql-42.2.5.jar file and I wrote the following JavaTest.java program:

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/* Import classes. */
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
 
public class JavaTest { 
  public static void main(String[] args) {
    /* Set default strings for the connection. */
    String url = "jdbc:postgresql://localhost:5432/videodb";
    String user = "student";
    String password = "student";
 
    /* Try the connection and statement. */
    try {
      Connection conn = DriverManager.getConnection(url, user, password);
      Statement st = conn.createStatement();
      ResultSet rs = st.executeQuery("SELECT VERSION()");
 
      if (rs.next()) {
        System.out.println(rs.getString(1));
      }
 
      /* Close the result set and statement. */
      rs.close();
      st.close();
    }
    catch (SQLException e) {
      Logger logger = Logger.getLogger(JavaTest.class.getName());
      logger.log(Level.SEVERE, e.getMessage(), e);
    }
  }
}

I compiled the JavaTest.java program and tested it. It failed with the following error:

FATAL: Ident authentication failed for user - Unable to connect to PostgreSQL

The failure occurred because I hadn’t allowed the connection in PostgreSQL’s pg_hba.conf file. I changed the following line in my pg_hba.conf file:

host    all             all             127.0.0.1/32            ident

to

host    all             all             127.0.0.1/32            trust

Then, I restarted the postgresql-11 service, like this:

systemctl restart postgresql-11.service

The JavaTest program ran successfully and returned:

PostgreSQL 11.5 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 9.1.1 20190503 (Red Hat 9.1.1-1), 64-bit

You can extend the logic to output a comma-separated value file by leveraging the JDBC help page, like this:

/* Import classes. */
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
 
/* Create class withonly a static method for runtime testing. */
public class JavaReturnSet { 
  public static void main(String[] args) {
    /* Set default strings for the connection. */
    String url = "jdbc:postgresql://localhost:5432/videodb";
    String user = "student";
    String password = "student";
 
    /* Try the connection and statement. */
    try {
      /* Set connection, statement, and result set. */
      Connection conn = DriverManager.getConnection(url, user, password);
      Statement st = conn.createStatement();
 
      /* Use the + to concatenate lines for query clarity. */
      ResultSet rs = st.executeQuery("SELECT m.account_number\n" +
                                     ",      CONCAT(c.last_name,', ',c.first_name)\n" +
                                     "FROM   member m JOIN contact c\n" +
                                     "ON     m.member_id = c.member_id");
 
      /* Get query metadata for subsequent management of results. */
      ResultSetMetaData rsmd = rs.getMetaData();
      String line;
 
      while (rs.next()) {
        /* Initialize the line output for each row. */
        line = "";
 
        /* Process the columns. */
        for (int i = 0; i < rsmd.getColumnCount(); i++) {
          if (rsmd.getColumnType(i + 1) == 12) {
            line = line + "\"" + rs.getString(i + 1) + "\"";
          }
          else {
            line = line + rs.getInt(i + 1);
          }
 
          /* Put a comma between output columns. */
          if (i < rsmd.getColumnCount() - 1) {
            line = line + ",";
          }
        }
        System.out.println(line);
      }
 
      /* Close the result set and statement. */
      rs.close();
      st.close();
    }
    catch (SQLException e) {
      Logger logger = Logger.getLogger(JavaReturnSet.class.getName());
      logger.log(Level.SEVERE, e.getMessage(), e);
    }
  }
}

As always, I hope this helps those looking for a clean solution.

Written by maclochlainn

November 2nd, 2019 at 11:46 pm

Posted in DBA,DevOps,Fedora,Java,Java 8,Linux,Postgres,PostgreSQL,sql

Tagged with ,

pgAdmin4 on Fedora 30

without comments

While attempting an install of pgAdmin and updating a Fedora 30 environment, I encountered a conflict on the upgrade of MySQL 8.0.17-1 to 8.0.17.2. The community-mysql-8.0.17-2.fc30.x86_64 had conflicts with:

  • mysql-community-client-8.0.17-1.fc30.x86_64 package
  • mysql-community-server-8.0.17-1.fc30.x86_64 package

I tried to update the system before install pgadmin4 with the following syntax:

dnf -y update && dnf -y install pgadmin4

The dnf utility raise the following MySQL package errors during transaction checking:

Display detailed console log →

Error: Transaction check error:
  file /usr/bin/mysql conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysql_config_editor conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqladmin conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqlbinlog conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqlcheck conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqldump conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqlimport conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqlpump conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqlshow conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqlslap conflicts between attempted installs of community-mysql-8.0.17-2.fc30.x86_64 and mysql-community-client-8.0.17-1.fc30.x86_64
  file /usr/bin/ibd2sdi conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/innochecksum conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/my_print_defaults conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/myisam_ftdump conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/myisamchk conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/myisamlog conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/myisampack conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/mysql_secure_installation conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/mysql_ssl_rsa_setup conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/mysql_tzinfo_to_sql conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/mysql_upgrade conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/mysqld_pre_systemd conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/bin/perror conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib/systemd/system/mysqld.service conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib/systemd/system/mysqld@.service conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/adt_null.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/auth_socket.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/component_audit_api_message_emit.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/component_log_filter_dragnet.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/component_log_sink_json.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/component_log_sink_syseventlog.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/component_validate_password.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/connection_control.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/ddl_rewriter.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/group_replication.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/ha_example.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/ha_mock.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/innodb_engine.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/keyring_file.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/keyring_udf.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/libmemcached.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/locking_service.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/mypluglib.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/mysql_clone.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/mysql_no_login.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/rewrite_example.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/rewriter.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/semisync_master.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/semisync_slave.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/validate_password.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/plugin/version_token.so conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/sbin/mysqld conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /var/lib/mysql conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /var/lib/mysql-keyring conflicts between attempted installs of community-mysql-server-8.0.17-2.fc30.x86_64 and mysql-community-server-8.0.17-1.fc30.x86_64
  file /usr/lib64/mysql/libmysqlclient.so.21.1.17 conflicts between attempted installs of community-mysql-libs-8.0.17-2.fc30.x86_64 and mysql-community-libs-8.0.17-1.fc30.x86_64

Since I’m not sure what’s wrong or how to fix it, I’ve put it in my queue of things to get to later. However, when I figure it out I’ll update this blog page with the solution or work around. If anybody knows the fix and would like to share, please let me know.

I removed the pending update packages with the following command:

dnf clean packages

Then, I simply installed pgadmin4 with the following command:

dnf -y install pgadmin4

Display detailed console log →

 

The pgadmin4 configuration instructions can be found for several Linux versions at Josphat Mutai’s Computing for Geeks web page. On Fedora 30, you need to do the following:

  • Install, start, and enable Apache as the httpd service unless you already have done that.
  • Copy the /etc/httpd/conf.d/pgadmin4.conf.sample file to /etc/httpd/conf.d/pgadmin4.conf, which is a new file.
  • Restart the httpd service to incorporate the pgadmin4 configuration file.

After that, you create the following new directories as the root or sudo user:

  • /var/lib/pgadmin4
  • /var/log/pgadmin4

You can make both directories with a single mkdir command, like:

mkdir -p /var/lib/pgadmin4 /var/log/pgadmin4

As the root or sudo user, change the ownership of these two directories to the apache user with the following syntax:

chown -R apache:apache /var/lib/pgadmin4 /var/log/pgadmin4

You add the following four statements to the config_distro.py file in the /usr/lib/python3.7/site-packages/pgadmin4-web directory as the root or sudo user:

LOG_FILE = '/var/log/pgadmin4/pgadmin4.log'
SQLITE_PATH = '/var/lib/pgadmin4/pgadmin4.db'
SESSION_DB_PATH = '/var/lib/pgadmin4/sessions'
STORAGE_DIR = '/var/lib/pgadmin4/storage'

You need to setup the pgadmin user with the following python3 command:

python3 /usr/lib/python3.7/site-packages/pgadmin4-web/setup.py

Enter the following values, a real email address and a password twice:

NOTE: Configuring authentication for SERVER mode.
 
Enter the email address and password to use for the initial pgAdmin user account:
 
Email address: admin@example.com   
Password: your_password
Retype password: your_password
pgAdmin 4 - Application Initialisation
======================================

Assuming you have an enabled firewall, you need to issue the following two commands as the root or sudo user:

rirewall-cmd --permanent --add-service=http
firewall-cmd --reload

You invoke pgAdmin4 from within a browser window with the following URL for a stand alone workstation (for a workstation on a DNS network you would enter pgadmin.domain.domain_type in lieu of localhost):

pgadmin/localhost/pgadmin4

You most likely will encounter an Internal Server Error, the recommended fix is reputed to be:

ausearch -c 'httpd' --raw | audit2allow -M my-httpd
semodule -X 300 -i my-httpd.pp

It didn’t work for me. At the end of the process, I have an Internal Server Error. It is something that I’ll try to fix next. The actual error message:

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
 
Please contact the server administrator at root@localhost to inform them of the time this error occurred, and the actions you performed just before this error.
 
More information about this error may be available in the server error log.

If somebody figures out the last step before I do, that’s great. Let me and everybody else know the mystery.

On a positive note, the pgadmin4 package provided the psycopg2 library. I had looked for it as a psycopg2 package but it is in python3-psycopg2 package.

Written by maclochlainn

September 21st, 2019 at 5:29 pm

Posted in Linux,MySQL,MySQL 8,pgAdmin4,Postgres,Python,Python 2.7,Python 3.x

Tagged with , , ,

Postgres & Sequences

without comments

Many developers already know about the change from int to serial in Postgres. Serial is simpler because it automatically makes the column not null and links it to a sequence. The sequence is created with the following naming convention:

table_name_column_name_seq

The Postgres serial type always has a start with value of 1. Though, you can alter it immediately after creating the table.

You can create a serial surrogate key column like this:

CREATE TABLE new_hire
( new_hire_id  SERIAL        CONSTRAINT new_hire_pk PRIMARY KEY
, first_name   VARCHAR(20)   NOT NULL
, middle_name  VARCHAR(20)
, last_name    VARCHAR(20)   NOT NULL
, hire_date    DATE          NOT NULL
, UNIQUE(first_name, middle_name, hire_date));

If you want the sequence to start with 1001, you can ALTER the sequence after creating the table. Before you change the sequence staring value, you may want to confirm the automatic name assigned to the sequence. You can do that with the following query:

SELECT pg_get_serial_sequence('new_hire','new_hire_id');

It should return:

     pg_get_serial_sequence      
---------------------------------
 public.new_hire_new_hire_id_seq
(1 row)

Here’s the syntax for changing the current starting value of a Postgres sequence:

ALTER SEQUENCE new_hire_new_hire_id_seq RESTART WITH 1001;

If you want more control, you still have it with the older syntax. The older way requires that you create the sequence before you create the table, like this:

CREATE SEQUENCE new_hire_s START WITH 1001;

Then, you create the new_hire table like this:

CREATE TABLE new_hire
( new_hire_id  INT           NOT NULL DEFAULT NEXTVAL('new_hire_s')
, first_name   VARCHAR(20)   NOT NULL
, middle_name  VARCHAR(20)
, last_name    VARCHAR(20)   NOT NULL
, hire_date    DATE          NOT NULL
, PRIMARY KEY(new_hire_id)
, UNIQUE(first_name, middle_name, hire_date));

You probably will test this from a file because tables are tedious type and usually much larger than the sample new_hire table. If you wonder how to do that, typing help from the psql> prompt will not reveal it. The key is the \i command, like this:

\i new_hire.sql

Unfortunately, the psql> command-line shell does not allow for embedding a means to log the activity of your script file. You must do that from the Linux command-line through redirecting the console to a log file.

The rules are pretty simple for logging file results:

 -a, --echo-all       echo all input from script
 -b, --echo-errors    echo failed commands
 -e, --echo-queries   echo commands sent to the server

Here’s an example connecting to a videodb database with a student user:

psql -d videodb -U student -W -f postgres_tables.sql -a &> postgres_tables.txt

As always, I hope this helps those looking for how to solve the puzzle of a new environment.

Written by maclochlainn

September 16th, 2019 at 12:39 am

Posted in Linux,Postgres,PostgreSQL,sql

Tagged with ,

Postgres 11 Video DB

without comments

Installing PostgreSQL 11 on Fedora, Version 30, requires an update to my previous instructions to create a sandboxed user. A sandboxed user can only access a non-data dictionary database with a password. In the real world, rather than a personal test instance you would configure users to include aspects of networking. However, this post is only showing you how to connect from the local server.

This post builds on my PostgreSQL Installation blog post and shows you how to create a tablespace, database, role, and user. It also shows you how to change the default configuration for how users connect to the database.

The following steps create a tablespace, database, role, and user:

  1. Create tablespace

The directory for the data dictionary changes with PostgreSQL has changed. You can find it with the following command:

postgres=# show data_directory;

This will return the following:

     data_directory     
------------------------
 /var/lib/pgsql/11/data
(1 row)

You need to create a physical videoDB subdirectory in the /var/lib/pgsql/11 directory. You can use the following syntax from the /var/lib/pgsql/11 directory to create the videoDB subdirectory:

mkdir videoDB
  1. Create Tablespace

You can create a video_db tablespace with the following syntax:

CREATE TABLESPACE video_db
  OWNER postgres
  LOCATION '/var/lib/pgsql/11/videoDB';

This will return the following:

CREATE TABLESPACE

You can query whether you successfully create the video_db tablespace with the following:

SELECT * FROM pg_tablespace;

It should return the following:

  spcname   | spcowner | spcacl | spcoptions 
------------+----------+--------+------------
 pg_default |       10 |        | 
 pg_global  |       10 |        | 
 video_db   |       10 |        | 
(3 rows)
  1. Create a Database

You can create a videodb database with the following syntax:

CREATE DATABASE videodb
  WITH OWNER = postgres
       ENCODING = 'UTF8'
       TABLESPACE = video_db
       LC_COLLATE = 'en_US.UTF-8'
       LC_CTYPE = 'en_US.UTF-8'
       CONNECTION LIMIT = -1;

You can verify the creation of the videodb with the following command:

postgres# \l

It should show you a display like the following:

                                  List of databases
   Name    |  Owner   | Encoding |   Collate   |    Ctype    |   Access privileges   
-----------+----------+----------+-------------+-------------+-----------------------
 postgres  | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | 
 template0 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
           |          |          |             |             | postgres=CTc/postgres
 template1 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
           |          |          |             |             | postgres=CTc/postgres
 videodb   | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =Tc/postgres         +
           |          |          |             |             | postgres=CTc/postgres+
           |          |          |             |             | dba=CTc/postgres
(4 rows)

Then, you can assign comment to the database with the following syntax:

COMMENT ON DATABASE videodb IS 'Video Database';
  1. Create a Role, Grant, and User

In this section you create a dba role, grant privileges on a videodb database to a role, and create a user with the role that you created previously with the following three statements. There are three steps in this sections.

  • The first step creates a dba role: 

    CREATE ROLE dba WITH SUPERUSER;
  • The second step grants all privileges on a videodb database to a dba role: 

    GRANT ALL PRIVILEGES ON DATABASE videodb TO dba;
  • The third step creates a student user with the dba role: 

    CREATE USER student
  WITH ROLE dba
       ENCRYPTED PASSWORD 'student';
  • It is possible that you may (and should if this is a new instance you are building) encounter an error when you try to connect as a sandboxed user. The syntax to connect as the student user is: 

    psql -d videodb -U student -W

    You may encounter this error:

    psql: FATAL:  Peer authentication failed for user "student"

    You can fix this in PostgreSQL 11 by changing the user access parameters in the pg_hba.conf configuration file. The file is found in the /var/lib/pgsql/11/data directory and you need to edit it as the root or postgres user.

    The default entry is:

    # TYPE  DATABASE        USER            ADDRESS                 METHOD
 
# "local" is for Unix domain socket connections only
local   all             all                                    peer

    You should replace it with the following:

    # TYPE  DATABASE        USER            ADDRESS                 METHOD
 
# "local" is for Unix domain socket connections only
local   postgres         all                                    peer
local   videodb          student                                md5

    After you save those changes in the pg_hba.conf file, you need to restart the PostgreSQL (postgresql-11) service. You can do that with the following command as the root user:

    service postgresql-11 restart

  1. Connect to the videodb as the student user

Once the postgresql-11 service is restarted, you can connect with the sandboxed student user with this syntax:

psql -d videodb -U student -W

If you did everything correctly, you should see the following after correctly providing the student password for the student user:

psql (11.4, server 11.5)
Type "help" for help.
 
videodb=>

After connecting to the videodb database, you can query the current database, like

SELECT current_database();

It should return the following:

 current_database 
------------------
 videodb
(1 row)

This has shown you how to create a videodb database, dba role, and student user.

Written by maclochlainn

September 5th, 2019 at 12:21 am

Posted in Fedora,Linux,PostgreSQL,psql,Unix

Tagged with ,

PostgreSQL on Fedora 30

with one comment

Installing PostreSQL 11 on Fedora 30 wasn’t straight forward but there were some instructions that helped. The first step requires you to update the yum repository, like this as the root user:

rpm -Uvh https://yum.postgresql.org/11/fedora/fedora-30-x86_64/pgdg-fedora-repo-latest.noarch.rpm

Then, you install the PostgreSQL with this command as the root user:

dnf install postgresql11-server

After installing the PostreSQL Server I got a few errors with the symbolic links failing to resolve in the log files. Then, I realized they only failed to create symbolic links because the fresh installation deploys executables directly to the /usr/bin directory.

Display detailed console log →

Retrieving https://yum.postgresql.org/11/fedora/fedora-30-x86_64/pgdg-fedora-repo-latest.noarch.rpm
warning: /var/tmp/rpm-tmp.MD4lRU: Header V4 DSA/SHA1 Signature, key ID 442df0f8: NOKEY
Verifying...                          ################################# [100%]
Preparing...                          ################################# [100%]
Updating / installing...
   1:pgdg-fedora-repo-42.0-4          ################################# [100%]
[root@localhost ~]# dnf install postgresql11-server
PostgreSQL 11 30 - x86_64                                                         215 kB/s | 585 kB     00:02    
PostgreSQL 10 30 - x86_64                                                         199 kB/s | 541 kB     00:02    
PostgreSQL 9.6 30 - x86_64                                                        295 kB/s | 515 kB     00:01    
PostgreSQL 9.5 30 - x86_64                                                        179 kB/s | 495 kB     00:02    
PostgreSQL 9.4 30 - x86_64                                                        269 kB/s | 469 kB     00:01    
Last metadata expiration check: 0:00:01 ago on Mon 19 Aug 2019 02:25:56 AM MDT.
Dependencies resolved.
==================================================================================================================
 Package                           Architecture         Version                        Repository            Size
==================================================================================================================
Installing:
 postgresql11-server               x86_64               11.5-1PGDG.f30                 pgdg11               4.8 M
Installing dependencies:
 postgresql11                      x86_64               11.5-1PGDG.f30                 pgdg11               1.7 M
 postgresql11-libs                 x86_64               11.5-1PGDG.f30                 pgdg11               374 k
 
Transaction Summary
==================================================================================================================
Install  3 Packages
 
Total download size: 6.9 M
Installed size: 32 M
Is this ok [y/N]: y
Downloading Packages:
(1/3): postgresql11-libs-11.5-1PGDG.f30.x86_64.rpm                                213 kB/s | 374 kB     00:01    
(2/3): postgresql11-11.5-1PGDG.f30.x86_64.rpm                                     698 kB/s | 1.7 MB     00:02    
(3/3): postgresql11-server-11.5-1PGDG.f30.x86_64.rpm                              1.5 MB/s | 4.8 MB     00:03    
------------------------------------------------------------------------------------------------------------------
Total                                                                             2.2 MB/s | 6.9 MB     00:03     
warning: /var/cache/dnf/pgdg11-cde8ad453ae6cd5b/packages/postgresql11-11.5-1PGDG.f30.x86_64.rpm: Header V4 DSA/SHA1 Signature, key ID 442df0f8: NOKEY
PostgreSQL 11 30 - x86_64                                                         1.6 MB/s | 1.7 kB     00:00    
Importing GPG key 0x442DF0F8:
 Userid     : "PostgreSQL RPM Building Project <pgsqlrpms-hackers@pgfoundry.org>"
 Fingerprint: 68C9 E2B9 1A37 D136 FE74 D176 1F16 D2E1 442D F0F8
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-PGDG
Is this ok [y/N]: y
Key imported successfully
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                          1/1 
  Installing       : postgresql11-libs-11.5-1PGDG.f30.x86_64                                                  1/3 
  Running scriptlet: postgresql11-libs-11.5-1PGDG.f30.x86_64                                                  1/3 
  Installing       : postgresql11-11.5-1PGDG.f30.x86_64                                                       2/3 
  Running scriptlet: postgresql11-11.5-1PGDG.f30.x86_64                                                       2/3 
failed to link /usr/bin/psql -> /etc/alternatives/pgsql-psql: /usr/bin/psql exists and it is not a symlink
failed to link /usr/bin/clusterdb -> /etc/alternatives/pgsql-clusterdb: /usr/bin/clusterdb exists and it is not a symlink
failed to link /usr/bin/createdb -> /etc/alternatives/pgsql-createdb: /usr/bin/createdb exists and it is not a symlink
failed to link /usr/bin/createuser -> /etc/alternatives/pgsql-createuser: /usr/bin/createuser exists and it is not a symlink
failed to link /usr/bin/dropdb -> /etc/alternatives/pgsql-dropdb: /usr/bin/dropdb exists and it is not a symlink
failed to link /usr/bin/dropuser -> /etc/alternatives/pgsql-dropuser: /usr/bin/dropuser exists and it is not a symlink
failed to link /usr/bin/pg_dump -> /etc/alternatives/pgsql-pg_dump: /usr/bin/pg_dump exists and it is not a symlink
failed to link /usr/bin/pg_dumpall -> /etc/alternatives/pgsql-pg_dumpall: /usr/bin/pg_dumpall exists and it is not a symlink
failed to link /usr/bin/pg_restore -> /etc/alternatives/pgsql-pg_restore: /usr/bin/pg_restore exists and it is not a symlink
failed to link /usr/bin/reindexdb -> /etc/alternatives/pgsql-reindexdb: /usr/bin/reindexdb exists and it is not a symlink
failed to link /usr/bin/vacuumdb -> /etc/alternatives/pgsql-vacuumdb: /usr/bin/vacuumdb exists and it is not a symlink
 
  Running scriptlet: postgresql11-server-11.5-1PGDG.f30.x86_64                                                3/3 
  Installing       : postgresql11-server-11.5-1PGDG.f30.x86_64                                                3/3 
  Running scriptlet: postgresql11-server-11.5-1PGDG.f30.x86_64                                                3/3 
  Verifying        : postgresql11-11.5-1PGDG.f30.x86_64                                                       1/3 
  Verifying        : postgresql11-libs-11.5-1PGDG.f30.x86_64                                                  2/3 
  Verifying        : postgresql11-server-11.5-1PGDG.f30.x86_64                                                3/3 
 
Installed:
  postgresql11-server-11.5-1PGDG.f30.x86_64                   postgresql11-11.5-1PGDG.f30.x86_64                  
  postgresql11-libs-11.5-1PGDG.f30.x86_64                    
 
Complete!

After installing the PostgreSQL Server 11, you need to initialize the database. You use the following command to initialize the database as the root user:

/usr/pgsql-11/bin/postgresql-11-setup initdb

It should return the following:

Initializing database ... OK

The PostgreSQL Server 11 database installs in the /var/lib/pgsql/11/data directory. You can list the contents, which should mirror these:

drwx------. 5 postgres postgres  4096 Aug 19 02:45 base
drwx------. 2 postgres postgres  4096 Aug 19 02:45 global
drwx------. 2 postgres postgres  4096 Aug 19 02:45 log
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_commit_ts
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_dynshmem
-rw-------. 1 postgres postgres  4269 Aug 19 02:45 pg_hba.conf
-rw-------. 1 postgres postgres  1636 Aug 19 02:45 pg_ident.conf
drwx------. 4 postgres postgres  4096 Aug 19 02:45 pg_logical
drwx------. 4 postgres postgres  4096 Aug 19 02:45 pg_multixact
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_notify
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_replslot
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_serial
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_snapshots
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_stat
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_stat_tmp
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_subtrans
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_tblspc
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_twophase
-rw-------. 1 postgres postgres     3 Aug 19 02:45 PG_VERSION
drwx------. 3 postgres postgres  4096 Aug 19 02:45 pg_wal
drwx------. 2 postgres postgres  4096 Aug 19 02:45 pg_xact
-rw-------. 1 postgres postgres    88 Aug 19 02:45 postgresql.auto.conf
-rw-------. 1 postgres postgres 23895 Aug 19 02:45 postgresql.conf

You need to enable and start the postgresql-11.service with the following commands as the root user:

systemctl enable postgresql-11.service
systemctl start postgresql-11.service

You can login to test the configuration as the root user, like this:

su - postgres -c "psql"

You will see something like this:

psql: /usr/pgsql-11/lib/libpq.so.5: no version information available (required by psql)
psql: /usr/pgsql-11/lib/libpq.so.5: no version information available (required by psql)
psql (11.4, server 11.5)
Type "help" for help.
 
postgres=#

The error message appear to indicate there’s a bug (at least Bug #15798 is similar). Specifically, a missing function in the libya.so.5 library. Determining that impact took some time because of what else I had in the queue.

The Bug (at least Bug #15798 gave part of the fix. The problem was figuring out where the LD_LIBRARY_PATH should really be set, and I sorted that out.

If you inspect the postgres home directory (/var/lib/pgsql), you’ll find the following .bash_profile file:

[ -f /etc/profile ] && source /etc/profile
PGDATA=/var/lib/pgsql/11/data
export PGDATA
# If you want to customize your settings,
# Use the file below. This is not overridden
# by the RPMS.
[ -f /var/lib/pgsql/.pgsql_profile ] && source /var/lib/pgsql/.pgsql_profile

Then, you create the .pgsql_profile file in that directory. You should put the following command in the file:

export set LD_LIBRARY_PATH=/usr/lib64 needle < /dev/null

Then, when you login as the postgres user:

psql -U postgres

You will see:

psql (11.4, server 11.5)
Type "help" for help.
 
postgres=#

or, you can login to test the configuration as the root user with the syntax used earlier:

su - postgres -c "psql"

You need to put the LD_LIBRARY_PATH environment variable in the .bashrc of users who will access the PostgreSQL 11 database.

As always, I hope this helps those working it from the ground up.

Written by maclochlainn

August 19th, 2019 at 3:06 am

Posted in Fedora,LAMP,Linux,PostgreSQL,psql

Tagged with , ,

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