Horton

Re: Re: proposal: schema variables

jian he <jian.universality@gmail.com>

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From: jian he <jian.universality@gmail.com>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Dmitry Dolgov <9erthalion6@gmail.com>, Laurenz Albe <laurenz.albe@cybertec.at>, Erik Rijkers <er@xs4all.nl>, Michael Paquier <michael@paquier.xyz>, Amit Kapila <amit.kapila16@gmail.com>, DUVAL REMI <REMI.DUVAL@cheops.fr>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-01-06T07:58:36Z
Lists: pgsql-hackers, pgsql-performance

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Move WAL sequence code into its own file

  2. Add ExplainState argument to pg_plan_query() and planner().

  3. Don't include access/htup_details.h in executor/tuptable.h

  4. Refactor to avoid code duplication in transformPLAssignStmt.

  5. Avoid including commands/dbcommands.h in so many places

  6. Restrict psql meta-commands in plain-text dumps.

  7. Split func.sgml into more manageable pieces

  8. Fix squashing algorithm for query texts

  9. EXPLAIN: Always use two fractional digits for row counts.

  10. Preliminary refactoring of plpgsql expression construction.

  11. plpgsql: pure parser and reentrant scanner

  12. Add some sanity checks in executor for query ID reporting

  13. Fix misleading error message context

  14. Add macros for looping through a List without a ListCell.

Attachments

comment out the changes in
src/backend/utils/cache/plancache.c

    // /* process session variables */
    // if (OidIsValid(parsetree->resultVariable))
    // {
    //     if (acquire)
    //         LockDatabaseObject(VariableRelationId, parsetree->resultVariable,
    //                            0, AccessShareLock);
    //     else
    //         UnlockDatabaseObject(VariableRelationId,
parsetree->resultVariable,
    //                              0, AccessShareLock);
    // }

    // else if (IsA(node, Param))
    // {
    //     Param       *p = (Param *) node;
    //     if (p->paramkind == PARAM_VARIABLE)
    //     {
    //         if (acquire)
    //             LockDatabaseObject(VariableRelationId, p->paramvarid,
    //                                0, AccessShareLock);
    //         else
    //             UnlockDatabaseObject(VariableRelationId, p->paramvarid,
    //                                  0, AccessShareLock);
    //     }
    // }
the regress tests are still successful, that means these code changes
don't have related tests.


SetSessionVariable(Oid varid, Datum value, bool isNull)
{
    create_sessionvars_hashtables();
    svar = (SVariable) hash_search(sessionvars, &varid, HASH_ENTER, &found);
    if (!found)
        setup_session_variable(svar, varid);
    /* if this fails, it won't change the stored value */
    set_session_variable(svar, value, isNull);
}
after set_session_variable,
we want to make sure that svar->is_valid is true,
svar->value = value and  svar->isnull= isNull.
Based on this, I've simplified the function set_session_variable,
refer v1-0001-minor-refactoring-set_session_variable.no-cfbot


we use PlannerGlobal
{
   Oid            basenodeSessionVarid;
   Bitmapset *checkSelectPermVarids;
}
to solve the self-assigned corner case SELECT privilege.
(let v1.a =v1.a; in this case, we need have SELECT priv for v1.a
but let v1.a = 1, we don't need SELECT priv for v1.a).

i found out these two field value(information) most case is the same
as PlannerGlobal.sessionVariables;
I came up with another solution, introduce a bool (Query.is_Variable_assigned),
and get rid of PlannerGlobal.basenodeSessionVarid,
PlannerGlobal.checkSelectPermVarids.
not sure it make sense to you, refer
v1-0002-refactoring-LET-statement-self-assign-privileg.no-cfbot