Avoid O(N^2) behavior when enlarging SPI tuple table in spi_printtup().
For no obvious reason, spi_printtup() was coded to enlarge the tuple
pointer table by just 256 slots at a time, rather than doubling the size at
each reallocation, as is our usual habit. For very large SPI results, this
makes for O(N^2) time spent in repalloc(), which of course soon comes to
dominate the runtime. Use the standard doubling approach instead.
This is a longstanding performance bug, so back-patch to all active
branches.
Neil Conway
Branch
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REL9_1_STABLE
Details
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http://git.postgresql.org/pg/commitdiff/87b8c9e12f3025b70bd040c42d7d5f39ef9314bc
Modified Files
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src/backend/executor/spi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)