Horton

Re: making relfilenodes 56 bits

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Andres Freund <andres@anarazel.de>, Heikki Linnakangas <hlinnaka@iki.fi>, Thomas Munro <thomas.munro@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-09-09T10:02:17Z
Lists: pgsql-hackers

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On Thu, Sep 8, 2022 at 4:10 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:

> On a separate note, while reviewing the latest patch I see there is some risk of using the unflushed relfilenumber in GetNewRelFileNumber() function.  Basically, in the current code, the flushing logic is tightly coupled with the logging new relfilenumber logic and that might not work with all the values of the VAR_RELNUMBER_NEW_XLOG_THRESHOLD.  So the idea is we need to keep the flushing logic separate from the logging, I am working on the idea and I will post the patch soon.

I have fixed the issue, so now we will track nextRelFileNumber,
loggedRelFileNumber and flushedRelFileNumber.  So whenever
nextRelFileNumber is just VAR_RELNUMBER_NEW_XLOG_THRESHOLD behind the
loggedRelFileNumber we will log VAR_RELNUMBER_PER_XLOG more
relfilenumbers.  And whenever nextRelFileNumber reaches the
flushedRelFileNumber then we will do XlogFlush for WAL upto the last
loggedRelFileNumber.  Ideally flushedRelFileNumber should always be
VAR_RELNUMBER_PER_XLOG number behind the loggedRelFileNumber so we can
avoid tracking the flushedRelFileNumber.  But I feel keeping track of
the flushedRelFileNumber looks cleaner and easier to understand.  For
more details refer to the code in GetNewRelFileNumber().

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com

Commits

  1. Fix typos in comments, code and documentation

  2. Increase width of RelFileNumbers from 32 bits to 56 bits.

  3. Move RelFileNumber declarations to common/relpath.h.

  4. Include RelFileLocator fields individually in BufferTag.

  5. Convert macros to static inline functions (buf_internals.h)

  6. Remove the restriction that the relmap must be 512 bytes.

  7. Change internal RelFileNode references to RelFileNumber or RelFileLocator.

  8. Reorder subskiplsn in pg_subscription to avoid alignment issues.

  9. Fix DROP {DATABASE,TABLESPACE} on Windows.

  10. Restructure smgr API as per recent proposal. smgr no longer depends on