TutorialDBA - Support | Training | Consultant

Active: query is running and session is hitting every threshold time, Idle in transaction: query is completed,and waiting for commit, session is hitting every threshold period. Idle in transaction (aborted): last or some statement was aborted due to network or syntax error (consider here some statement executed succefully but some one only got issue),Similar to idle in transaction, except one of the statements in the transaction caused an error. Idle : session timeout and query executed and query has been committed Disabled:If track activities is disabled in this backend. Note : So Before​ closing session you have to issue commit otherwise work_mem will not release that particular session 9.6 parameter : idle_in_transaction_session_timeout Killing all idle connection script : https://www.tutorialdba.com/2017/12/script-to-kill-all-idle-connection-in.html

A common issue with databases: The guy at floor 2 did some work on the database and then rashly left for lunch because the lady on floor 1 is already waiting for him. Unfortunately he did not close his transaction and now his session is blocking others. In PostgreSQL this might be even worse as all tuples modified by this transaction are not available for vacuum until the transaction is either committed or aborted. In PostgreSQL 9.6 there will be a way to minimize this risk. As always with PostgreSQL: If someone wants to add something to PostgreSQL core it starts with a mail tread. The result was a new parameter called idle_in_transaction_session_timeout. Lets see how this works. The default value of idle_in_transaction_session_timeout is 0 , which means disabled: (postgres@[local]:5432) [postgres] > show idle_in_transaction_session_timeout; idle_in_transaction_session_timeout ------------------------------------- 0 (1 row) I’ll set it to one minute… (postgres@[...

What is pg_stat_activity? pg_stat_activity is a PostgreSQL system view that is a good first place to start when you want to find out what is going on with your PostgreSQL installation. Aside 1 If you need to make a connection to a PostgreSQL installation, a good first place to start is username postgres dbname postgres Any default PostgreSQL install will have both this user and database. Tool makers know this convention, and design tools that connect using these defaults. http://www.postgresql.org/docs/9.4/interactive/creating-cluster.html Aside 2 Here's how you list all the databases in a PostgreSQL cluster: mwood@mwod-ThinkPad-X220:~$ psql -U postgres -l List of databases ┌───────────┬──────────┬──────────┬─────────┬───────┬───────────────────────┐ │ Name │ Owner │ Encoding │ Collate │ Ctype │ Access privileges │ ├───────────┼──────────┼──────────┼─────────┼───────┼───────────────────────┤ │ postgres │ postgre...

The catalog  pg_namespace  stores namespaces. A namespace is the structure underlying SQL schemas: each namespace can have a separate collection of relations, types, etc. without name conflicts. Name Type References Description oid oid Row identifier (hidden attribute; must be explicitly selected) nspname name Name of the namespace nspowner oid pg_authid .oid Owner of the namespace nspacl aclitem[] Access privileges; see  GRANT  and  REVOKE  for details

The pg_stat_all_indexes view will contain one row for each index in the current database, showing statistics about accesses to that specific index. The pg_stat_user_indexes and pg_stat_sys_indexes views contain the same information, but filtered to only show user and system indexes respectively. Indexes can be used via either simple index scans or "bitmap" index scans. In a bitmap scan the output of several indexes can be combined via AND or OR rules, so it is difficult to associate individual heap row fetches with specific indexes when a bitmap scan is used. Therefore, a bitmap scan increments the pg_stat_all_indexes.idx_tup_read count(s) for the index(es) it uses, and it increments the pg_stat_all_tables.idx_tup_fetch count for the table, but it does not affect pg_stat_all_indexes.idx_tup_fetch. Note: The idx_tup_read and idx_tup_fetch counts can be different even without any use of bitmap scans, because idx_tup_read counts index entries retrieved from the index while ...