Re: question on audit columns - Mailing list pgsql-general
| From | Ron Johnson |
|---|---|
| Subject | Re: question on audit columns |
| Date | |
| Msg-id | CANzqJaC1Ayhmjg2XA5nfeg-Yy8T1vmNXO+bHkWRgV2N4wfQVVw@mail.gmail.com Whole thread Raw |
| In response to | Re: question on audit columns (yudhi s <learnerdatabase99@gmail.com>) |
| List | pgsql-general |
On Wed, Sep 4, 2024 at 9:10 AM yudhi s <learnerdatabase99@gmail.com> wrote:
On Wed, Sep 4, 2024 at 6:29 PM Muhammad Usman Khan <usman.k@bitnine.net> wrote:Hi,
In your scenario, triggers can add some overhead since they require extra processing after each update operation. Considering the size of your table and the high transaction volume, you need to observe that this might significantly affect performance.
On Wed, 4 Sept 2024 at 17:50, yudhi s <learnerdatabase99@gmail.com> wrote:Hello,In postgres database , we have all the tables with audit columns like created_by_user, created_timestamp,updated_by_user, updated_timestamp. So we have these fields that were supposed to be populated by the time at which the insert/update operation happened on the database but not at the application level. So we are planning to populate the created_by_user, created_timestamp columns by setting a default value of "current_timestamp" and "current_user" for the two columns, but no such this is available to populate while we do the update of the row, so the only option seems to be through a trigger.So wanted to check with the experts here ,considering the table will be DML heavy table (300M+ transactions will be inserted daily), Is is okay to have the trigger for this table for populating all the audit columns or should we keep default for created_by_user, created_timestamp and just trigger for the update related two audit column? Basically wanted to see, if the default value does the same thing as a trigger or it does something more optimally than trigger?RegardsYudhiThank you so much. So do you mean to say that , we should add default values for the create_timestamp and create_user_id as current_timestamp and current_user,
That's the simplest way. But the application can overwrite those fields.
but for update_user_id and update_timestamp , we can ask the application to update the values manually , whenever they are executing the update statement on the rows?
If they're really strict, you might need INSERT and UPDATE triggers that call security defined functions which write into a separate table not accessible by the application. That table would have the application table's PK, created_by_user, created_timestamp, updated_by_user and updated_timestamp.
Would that table have a LOT of records? Sure.
Would it add overhead? Sure.
But the subsequently beefier hardware requirements and care in designing the physical schema (for example, audit tables in a separate tablespace and pg_wal/ on separate disk controllers, or a 10Gb SAN) are the price you pay for strict audit requirements.
Of course, if the audit requirements are minimal, then sure, "default values and the application" are Good Enough.
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