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[doc][2024.2.1] Added limitations for YSQL Connection Manager #25458

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Jan 14, 2025
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[doc][2024.2.1] Added limitations for YSQL Connection Manager #25458

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Limitations for conn mgr
rahulb-yb Dec 31, 2024
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rahulb-yb Jan 9, 2025
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rahulb-yb Jan 9, 2025
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rahulb-yb Jan 10, 2025
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Update docs/content/stable/explore/going-beyond-sql/connection-mgr-ys…
ddhodge Jan 10, 2025
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8 changes: 4 additions & 4 deletions docs/content/stable/explore/going-beyond-sql/connection-mgr-ysql.md
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Expand Up @@ -101,9 +101,9 @@ The following table describes YB-TServer flags related to YSQL Connection Manage
## Limitations

- Changes to default GUC values for a user or database (ALTER ROLE SET/ALTER DATABASE SET queries) may reflect in other pre-existing active sessions.
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can you be more specific? only flags, not YSQL configuration parameters, are listed above - so what values are you talking about?

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GUC values have nothing to do with anything previously mentioned on this page; this category of session-specific database objects may not have the correct behaviour when using connection manager as per the limitation I have mentioned. I also use the term "may" on this line because trying to explain the scenario(s) where this behaviour can be seen would dive into too many technical details for what is a very rare corner case.

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- Connection Manager can only support upto a total of 10,000 pools to route. This includes pools corresponding to dropped users and databases as well.
- Prepared statements may be visible to other sessions within the same connection pool. [#24652](https://github.com/yugabyte/yugabyte-db/issues/24652)
- YSQL Connection Manager can route up to 10,000 connection pools. This includes pools corresponding to dropped users and databases.
- Prepared statements may be visible to other sessions in the same connection pool. [#24652](https://github.com/yugabyte/yugabyte-db/issues/24652)
- Attempting to use DEALLOCATE/DEALLOCATE ALL queries can result in unexpected behavior. [#24653](https://github.com/yugabyte/yugabyte-db/issues/24653)
- As of now, Connection Manager does not facilitate custom configurations per pool. All configurations used will apply to every pool that Connection Manager routes through.
- With connection manager enabled, the backend PID stored using JDBC drivers may not accurate. This does not affect backend-specific functionalities (eg. cancel queries), but this PID should not be used to identify the backend process.
- Currently, you can't apply custom configurations to individual pools. The YSQL Connection Manager configuration applies to all pools.
- When YSQL Connection Manager is enabled, the backend PID stored using JDBC drivers may not accurate. This does not affect backend-specific functionalities (for example, cancel queries), but this PID should not be used to identify the backend process.
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- `currval` and `nextval` functions do not work by default with connection manager enabled. They can be supported with the help of the `ysql_conn_mgr_sequence_support_mode` flag.
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@ddhodge ddhodge Jan 5, 2025 •
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Suggested change
- `currval` and `nextval` functions do not work by default with connection manager enabled. They can be supported with the help of the `ysql_conn_mgr_sequence_support_mode` flag.
- By default, `currval` and `nextval` functions do not work when YSQL Connection Manager is enabled. To support these functions, use the `ysql_conn_mgr_sequence_support_mode` flag.

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the ysql_conn_mgr_sequence_support_mode is not a boolean flag, I can try to incorporate this comment in a similar fashion

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I changed the suggested text slightly

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