logtape.c: allocate read buffer even for an empty tape.
Prior to this commit, the read buffer was allocated at the time the tape
was rewound; but as an optimization, would not be allocated at all if
the tape was empty.
That optimization meant that it was valid to have a rewound tape with
the buffer set to NULL, but only if a number of conditions were met
and only if the API was used properly. After 7fdd919a refactored the
code to support lazily-allocating the buffer, Coverity started
complaining.
The optimization for empty tapes doesn't seem important, so just
allocate the buffer whether the tape has any data or not.
Discussion: https://postgr.es/m/20351.1581868306%40sss.pgh.pa.us
Branch
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master
Details
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https://git.postgresql.org/pg/commitdiff/8021985d791902a9eeda51acdede759fbc67ae01
Modified Files
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src/backend/utils/sort/logtape.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)