Just returned from vacation ...
Tom Lane wrote:
I notice that we have in md.c
TRACE_POSTGRESQL_SMGR_MD_READ_DONE(forknum, blocknum, reln->smgr_rnode.spcNode,
reln->smgr_rnode.dbNode, reln->smgr_rnode.relNode, relpath(reln->smgr_rnode,
forknum), nbytes, BLCKSZ);
TRACE_POSTGRESQL_SMGR_MD_WRITE_DONE(forknum, blocknum, reln->smgr_rnode.spcNode,
reln->smgr_rnode.dbNode, reln->smgr_rnode.relNode, relpath(reln->smgr_rnode,
forknum), nbytes, BLCKSZ);
relpath() returns a palloc'd string, which will not get freed, which
means that any serious use of these probe points will shortly blow out
the backend's memory. So far as I can see the path argument is
redundant with the other probe arguments and we might as well just
remove it --- objections?
agreed; the other arguments can be used to get the same result.
There's another problem in tuplesort.c:
TRACE_POSTGRESQL_SORT_DONE(state->tapeset,
(state->tapeset ? LogicalTapeSetBlocks(state->tapeset) :
(state->allowedMem - state->availMem + 1023) / 1024));
This is called after state->tapeset has been freed, which means that the
LogicalTapeSetBlocks call will very likely give a wrong answer,
especially in assert-enabled builds but maybe even in a regular one.
Good catch and thanks for reviewing the probes.
-Robert
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