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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2017-06-05 12:05:42 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2017-06-05 12:05:42 -0400 |
| commit | d4663350646ca0c069a36d906155a0f7e3372eb7 (patch) | |
| tree | 0bc14a79fae8af098aeea21b7a018cf220c02a6e /src/backend/executor/execParallel.c | |
| parent | af51fea039bb8e00066d68d919312df1701dc03e (diff) | |
| download | postgresql-d4663350646ca0c069a36d906155a0f7e3372eb7.tar.gz postgresql-d4663350646ca0c069a36d906155a0f7e3372eb7.zip | |
Don't be so trusting that shm_toc_lookup() will always succeed.
Given the possibility of race conditions and so on, it seems entirely
unsafe to just assume that shm_toc_lookup() always finds the key it's
looking for --- but that was exactly what all but one call site were
doing. To fix, add a "bool noError" argument, similarly to what we
have in many other functions, and throw an error on an unexpected
lookup failure. Remove now-redundant Asserts that a rather random
subset of call sites had.
I doubt this will throw any light on buildfarm member lorikeet's
recent failures, because if an unnoticed lookup failure were involved,
you'd kind of expect a null-pointer-dereference crash rather than the
observed symptom. But you never know ... and this is better coding
practice even if it never catches anything.
Discussion: https://postgr.es/m/9697.1496675981@sss.pgh.pa.us
Diffstat (limited to 'src/backend/executor/execParallel.c')
| -rw-r--r-- | src/backend/executor/execParallel.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c index 06101800160..1c02fa140b0 100644 --- a/src/backend/executor/execParallel.c +++ b/src/backend/executor/execParallel.c @@ -341,7 +341,7 @@ ExecParallelSetupTupleQueues(ParallelContext *pcxt, bool reinitialize) mul_size(PARALLEL_TUPLE_QUEUE_SIZE, pcxt->nworkers)); else - tqueuespace = shm_toc_lookup(pcxt->toc, PARALLEL_KEY_TUPLE_QUEUE); + tqueuespace = shm_toc_lookup(pcxt->toc, PARALLEL_KEY_TUPLE_QUEUE, false); /* Create the queues, and become the receiver for each. */ for (i = 0; i < pcxt->nworkers; ++i) @@ -684,7 +684,7 @@ ExecParallelGetReceiver(dsm_segment *seg, shm_toc *toc) char *mqspace; shm_mq *mq; - mqspace = shm_toc_lookup(toc, PARALLEL_KEY_TUPLE_QUEUE); + mqspace = shm_toc_lookup(toc, PARALLEL_KEY_TUPLE_QUEUE, false); mqspace += ParallelWorkerNumber * PARALLEL_TUPLE_QUEUE_SIZE; mq = (shm_mq *) mqspace; shm_mq_set_sender(mq, MyProc); @@ -705,14 +705,14 @@ ExecParallelGetQueryDesc(shm_toc *toc, DestReceiver *receiver, char *queryString; /* Get the query string from shared memory */ - queryString = shm_toc_lookup(toc, PARALLEL_KEY_QUERY_TEXT); + queryString = shm_toc_lookup(toc, PARALLEL_KEY_QUERY_TEXT, false); /* Reconstruct leader-supplied PlannedStmt. */ - pstmtspace = shm_toc_lookup(toc, PARALLEL_KEY_PLANNEDSTMT); + pstmtspace = shm_toc_lookup(toc, PARALLEL_KEY_PLANNEDSTMT, false); pstmt = (PlannedStmt *) stringToNode(pstmtspace); /* Reconstruct ParamListInfo. */ - paramspace = shm_toc_lookup(toc, PARALLEL_KEY_PARAMS); + paramspace = shm_toc_lookup(toc, PARALLEL_KEY_PARAMS, false); paramLI = RestoreParamList(¶mspace); /* @@ -843,7 +843,7 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc) /* Set up DestReceiver, SharedExecutorInstrumentation, and QueryDesc. */ receiver = ExecParallelGetReceiver(seg, toc); - instrumentation = shm_toc_lookup(toc, PARALLEL_KEY_INSTRUMENTATION); + instrumentation = shm_toc_lookup(toc, PARALLEL_KEY_INSTRUMENTATION, true); if (instrumentation != NULL) instrument_options = instrumentation->instrument_options; queryDesc = ExecParallelGetQueryDesc(toc, receiver, instrument_options); @@ -858,7 +858,7 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc) InstrStartParallelQuery(); /* Attach to the dynamic shared memory area. */ - area_space = shm_toc_lookup(toc, PARALLEL_KEY_DSA); + area_space = shm_toc_lookup(toc, PARALLEL_KEY_DSA, false); area = dsa_attach_in_place(area_space, seg); /* Start up the executor */ @@ -875,7 +875,7 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc) ExecutorFinish(queryDesc); /* Report buffer usage during parallel execution. */ - buffer_usage = shm_toc_lookup(toc, PARALLEL_KEY_BUFFER_USAGE); + buffer_usage = shm_toc_lookup(toc, PARALLEL_KEY_BUFFER_USAGE, false); InstrEndParallelQuery(&buffer_usage[ParallelWorkerNumber]); /* Report instrumentation data if any instrumentation options are set. */ |