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base repository: postgresql-cfbot/postgresql
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  • 5 commits
  • 53 files changed
  • 2 contributors

Commits on Aug 10, 2025

  1. Store working memory limit per Plan/SubPlan, rather than in GUC 

    This commit moves the working-memory limit that an executor node checks, at
runtime, from the "work_mem" and "hash_mem_multiplier" GUCs, to a new
list, "workMemLimits", added to the PlannedStmt node. At runtimem an exec
node checks its limit by looking up the list element corresponding to its
plan->workmem_id field.

Indirecting the workMemLimit via a List index allows us to handle SubPlans
as well as Plans. It also allows a future extension to set limits on
individual Plans/SubPlans, without needing to re-traverse the Plan +
Expr tree.

To preserve backward, this commit also copies the "work_mem", etc., values
from the existing GUCs to the new field. This means that this commit is
just a refactoring, and doesn't change any behavior.

This "workmem_id" field is on the Plan node, instead of the corresponding
PlanState, because the workMemLimit needs to be set before we can call
ExecInitNode().
    James Hunter authored and Commitfest Bot committed Aug 10, 2025
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  2. Add "workmem" estimates to Path node and PlannedStmt 

    To allow for future optimizers to make decisions at Path time, this commit
aggregates the Path's total working memory onto the Path's "workmem" field,
normalized to a minimum of 64 KB and rounded up to the next whole KB.

To allow future hooks to override ExecAssignWorkMem(), this commit then
breaks that total working memory into per-data structure working memory,
and stores it, next to the workMemLimit, on the PlannedStmt.
    James Hunter authored and Commitfest Bot committed Aug 10, 2025
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  3. Add EXPLAIN (work_mem on) command option 

    So that users can see how much working memory a query is likely to use, as
well as how much memory it will be limited to, this commit adds an
EXPLAIN (work_mem on) command option that displays the workmem estimate
and limit, added in the previous two commits.
    James Hunter authored and Commitfest Bot committed Aug 10, 2025
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  4. Add "workmem_hook" to allow extensions to override per-node work_mem

    James Hunter authored and Commitfest Bot committed Aug 10, 2025
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  5. [CF 5595] Track and display estimated "work_mem" as well as limit, vi… 

    …a EXPLAIN (work_mem on); add hook to override work_mem limits; add extension to override using "workmem.query_work_mem" GUC

This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/5595

The branch will be overwritten each time a new patch version is posted to
the thread, and also periodically to check for bitrot caused by changes
on the master branch.

Patch(es): https://www.postgresql.org/message-id/[email protected]
Author(s): James Hunter
    Commitfest Bot committed Aug 10, 2025
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