[pgpool-committers: 6168] Re: pgpool: Fix occasional query hang while processing DEALLOCATE.

[Muhammad Usama]

Hi Ishii-San

This commit is causing the compilation failure with the below error.

context/pool_query_context.c: In function ‘where_to_send_deallocate’:
context/pool_query_context.c:1487:17: error: ‘POOL_QUERY_CONTEXT’ has no
member named ‘load_balance_node_id’
    query_context->load_balance_node_id =
msg->query_context->load_balance_node_id;
                 ^
context/pool_query_context.c:1487:60: error: ‘POOL_QUERY_CONTEXT’ has no
member named ‘load_balance_node_id’
    query_context->load_balance_node_id =
msg->query_context->load_balance_node_id;

Thanks
Best Regards
Muhammad Usama


On Mon, Sep 16, 2019 at 6:23 AM Tatsuo Ishii <ishii at sraoss.co.jp> wrote:

> Fix occasional query hang while processing DEALLOCATE.
>
> When DEALLOCATE tries to remove a named statement, it inherits
> where_to_send map of the named statement in
> where_to_send_deallocate(). However it forgot to copy the load balance
> node id in the query context of the named statement. This made sending
> query to backend not happen: if the target node id is different from
> query_context->load_balance_node_id nor primary node id,
> pool_virtual_master_db_node_id (it is called as MASTER_NODE_ID)
> returns primary node id, and pool_send_and_wait(MASTER_NODE_ID)
> ignores the request because VALID_BACKEND returns false in this case
> (MASTER_NODE_ID = primary node id is not in the where_to_send map). As
> a result, following check_error() waits for response from backend in
> vain.
>
> Fix is, let where_to_send_deallocate() copy load balance node id from
> the query context of the previous named statement.
>
> Per bug 546.
>
> Branch
> ------
> V4_0_STABLE
>
> Details
> -------
>
> https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=83c1988d3c8bdd0ecbdf6a3d28371febee556483
>
> Modified Files
> --------------
> src/context/pool_query_context.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
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