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c56e8af75e
This comment mentions that we check that the configured number of backends does not exceed MAX_BACKENDS in RegisterBackgroundWorker() and relevant GUC check hooks, neither of which has those checks anymore. To fix, adjust this comment to say that we do the check in InitializeMaxBackends(). Oversights in commits6bc8ef0b7fand0b1fe1413e. Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/Z7zOEzz8lNjaU9yf%40nathan
57 lines
2.1 KiB
C
57 lines
2.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* procnumber.h
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* definition of process number
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*
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*
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* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/storage/procnumber.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PROCNUMBER_H
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#define PROCNUMBER_H
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/*
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* ProcNumber uniquely identifies an active backend or auxiliary process.
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* It's assigned at backend startup after authentication, when the process
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* adds itself to the proc array. It is an index into the proc array,
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* starting from 0. Note that a ProcNumber can be reused for a different
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* backend immediately after a backend exits.
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*/
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typedef int ProcNumber;
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#define INVALID_PROC_NUMBER (-1)
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/*
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* Note: MAX_BACKENDS_BITS is 18 as that is the space available for buffer
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* refcounts in buf_internals.h. This limitation could be lifted by using a
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* 64bit state; but it's unlikely to be worthwhile as 2^18-1 backends exceed
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* currently realistic configurations. Even if that limitation were removed,
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* we still could not a) exceed 2^23-1 because inval.c stores the ProcNumber
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* as a 3-byte signed integer, b) INT_MAX/4 because some places compute
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* 4*MaxBackends without any overflow check. We check that the configured
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* number of backends does not exceed MAX_BACKENDS in InitializeMaxBackends().
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*/
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#define MAX_BACKENDS_BITS 18
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#define MAX_BACKENDS ((1U << MAX_BACKENDS_BITS)-1)
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/*
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* Proc number of this backend (same as GetNumberFromPGProc(MyProc))
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*/
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extern PGDLLIMPORT ProcNumber MyProcNumber;
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/* proc number of our parallel session leader, or INVALID_PROC_NUMBER if none */
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extern PGDLLIMPORT ProcNumber ParallelLeaderProcNumber;
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/*
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* The ProcNumber to use for our session's temp relations is normally our own,
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* but parallel workers should use their leader's proc number.
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*/
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#define ProcNumberForTempRelations() \
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(ParallelLeaderProcNumber == INVALID_PROC_NUMBER ? MyProcNumber : ParallelLeaderProcNumber)
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#endif /* PROCNUMBER_H */
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