Last accessed timestamp of a Netezza table? - sql

Question

Does anyone know of a query that gives me details on the last time a Netezza table was accessed for any of the operations (select, insert or update) ?

Answer 1

Depending on your setup you may want to try the following query:
select *
from _v_qryhist
where lower(qh_sql) like '%tablename %'

Answer 2

There are a collection of history views in Netezza that should provide the information you require.

Answer 3

Netezza does not track this information in the catalog, so you will typically have to mine that from the query history database, if one is configured.
Modern Netezza query history information is typically stored in a dedicated database. Depending on permissions, you may be able to see if history collection is enabled, and which database it is using with the following command. Apologies in advance for the screen-breaking wrap to come.
SYSTEM.ADMIN(ADMIN)=> show history configuration;
CONFIG_NAME | CONFIG_DBNAME | CONFIG_DBTYPE | CONFIG_TARGETTYPE | CONFIG_LEVEL | CONFIG_HOSTNAME | CONFIG_USER | CONFIG_PASSWORD | CONFIG_LOADINTERVAL | CONFIG_LOADMINTHRESHOLD | CONFIG_LOADMAXTHRESHOLD | CONFIG_DISKFULLTHRESHOLD | CONFIG_STORAGELIMIT | CONFIG_LOADRETRY | CONFIG_ENABLEHIST | CONFIG_ENABLESYSTEM | CONFIG_NEXT | CONFIG_CURRENT | CONFIG_VERSION | CONFIG_COLLECTFILTER | CONFIG_KEYSTORE_ID | CONFIG_KEY_ID | KEYSTORE_NAME | KEY_ALIAS | CONFIG_SCHEMANAME | CONFIG_NAME_DELIMITED | CONFIG_DBNAME_DELIMITED | CONFIG_USER_DELIMITED | CONFIG_SCHEMANAME_DELIMITED
-------------+---------------+---------------+-------------------+--------------+-----------------+-------------+---------------------------------------+---------------------+-------------------------+-------------------------+--------------------------+---------------------+------------------+-------------------+---------------------+-------------+----------------+----------------+----------------------+--------------------+---------------+---------------+-----------+-------------------+-----------------------+-------------------------+-----------------------+-----------------------------
ALL_HIST_V3 | NEWHISTDB | 1 | 1 | 20 | localhost | HISTUSER | aFkqABhjApzE$flT/vZ7hU0vAflmU2MmPNQ== | 5 | 4 | 20 | 0 | 250 | 1 | f | f | f | t | 3 | 1 | 0 | 0 | | | HISTUSER | f | f | f | f
(1 row)
Also make note of the CONFIG_VERSION, as it will come into play when crafting the following query example. In my case, I happen to be using the version 3 format of the query history database.
Assuming history collection is configured, and that you have access to the history database, you can get the information you're looking for from the tables and views in that database. These are documented here. The following is an example, which reports when the given table was the target of a successful insert, update, or delete by referencing the "usage" column. Here I use one of the history table helper functions to unpack that column.
SELECT FORMAT_TABLE_ACCESS(usage),
hq.submittime
FROM "$v_hist_queries" hq
INNER JOIN "$hist_table_access_3" hta
USING (NPSID, NPSINSTANCEID, OPID, SESSIONID)
WHERE hq.dbname = 'PROD'
AND hta.schemaname = 'ADMIN'
AND hta.tablename = 'TEST_1'
AND hq.SUBMITTIME > '01-01-2015'
AND hq.SUBMITTIME <= '08-06-2015'
AND
(
instr(FORMAT_TABLE_ACCESS(usage),'ins') > 0
OR instr(FORMAT_TABLE_ACCESS(usage),'upd') > 0
OR instr(FORMAT_TABLE_ACCESS(usage),'del') > 0
)
AND status=0;
FORMAT_TABLE_ACCESS | SUBMITTIME
---------------------+----------------------------
ins | 2015-06-16 18:32:25.728042
ins | 2015-06-16 17:46:14.337105
ins | 2015-06-16 17:47:14.430995
(3 rows)
You will need to change the digit at the end of the $v_hist_table_access_3 view to match your query history version.