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Fix memory handling during scans

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Scan functions cannot be called on a per-tuple memory context as they
might allocate data that need to live until the end of the scan. Fix
this in a couple of places to ensure correct memory handling.

Fixes #4148, #4145
This commit is contained in:
Erik Nordström 2022-03-11 17:46:05 +01:00 committed by Erik Nordström
parent a759b2b2b9
commit b954c00fa8
4 changed files with 26 additions and 24 deletions
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4
CHANGELOG.md
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@ -8,6 +8,10 @@ accidentally triggering the load of a previous DB version.**
**Bugfixes**
* #4122 Fix segfault on INSERT into distributed hypertable
* #4161 Fix memory handling during scans
**Thanks**
* @abrownsword for reporting a crash in the telemetry reporter
## 2.6.0 (2022-02-16)
This release is medium priority for upgrade. We recommend that you upgrade at the next available opportunity.

2
src/chunk_scan.c
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@ -252,9 +252,9 @@ ts_chunk_scan_by_constraints(const Hyperspace *hs, const List *dimension_vecs,
prev_chunk_oid = chunk->table_id;
}
MemoryContextSwitchTo(work_mcxt);
/* Only one chunk should match */
Assert(ts_scan_iterator_next(&chunk_it) == NULL);
MemoryContextSwitchTo(work_mcxt);
}
}

2
src/scan_iterator.c
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@ -56,5 +56,7 @@ ts_scan_iterator_scan_key_init(ScanIterator *iterator, AttrNumber attributeNumbe
TSDLLEXPORT void
ts_scan_iterator_rescan(ScanIterator *iterator)
{
MemoryContext oldmcxt = MemoryContextSwitchTo(iterator->scankey_mcxt);
ts_scanner_rescan(&iterator->ctx, NULL);
MemoryContextSwitchTo(oldmcxt);
}

42
src/telemetry/stats.c
View File

@ -27,7 +27,6 @@ typedef struct StatsContext
{
TelemetryStats *stats;
ScanIterator compressed_chunk_stats_iterator;
bool iterator_valid;
} StatsContext;
/*
@ -338,27 +337,25 @@ static bool
get_chunk_compression_stats(StatsContext *statsctx, const Chunk *chunk,
Form_compression_chunk_size compr_stats)
{
TupleInfo *ti;
MemoryContext oldmcxt;
if (!ts_chunk_is_compressed(chunk))
return false;
/* Need to execute the scan functions on the long-lived memory context */
oldmcxt = MemoryContextSwitchTo(statsctx->compressed_chunk_stats_iterator.scankey_mcxt);
ts_scan_iterator_scan_key_reset(&statsctx->compressed_chunk_stats_iterator);
ts_scan_iterator_scan_key_init(&statsctx->compressed_chunk_stats_iterator,
Anum_compression_chunk_size_pkey_chunk_id,
BTEqualStrategyNumber,
F_INT4EQ,
Int32GetDatum(chunk->fd.id));
ts_scan_iterator_start_or_restart_scan(&statsctx->compressed_chunk_stats_iterator);
ti = ts_scan_iterator_next(&statsctx->compressed_chunk_stats_iterator);
MemoryContextSwitchTo(oldmcxt);
if (statsctx->iterator_valid)
{
ts_scan_iterator_rescan(&statsctx->compressed_chunk_stats_iterator);
}
else
{
ts_scan_iterator_start_scan(&statsctx->compressed_chunk_stats_iterator);
statsctx->iterator_valid = true;
}
if (ts_scan_iterator_next(&statsctx->compressed_chunk_stats_iterator))
if (ti)
{
Form_compression_chunk_size fd;
bool should_free;
@ -379,9 +376,8 @@ get_chunk_compression_stats(StatsContext *statsctx, const Chunk *chunk,
/*
* Should only get here if a compressed chunk is missing stats for some
* reason. The iterator will automatically close if no tuple is found, so
* need to make sure it is re-opened next time this function is called.
* it will be re-opened next time this function is called.
*/
statsctx->iterator_valid = false;
return false;
}
@ -496,7 +492,6 @@ ts_telemetry_stats_gather(TelemetryStats *stats)
MemoryContext oldmcxt, relmcxt;
StatsContext statsctx = {
.stats = stats,
.iterator_valid = false,
};
MemSet(stats, 0, sizeof(*stats));
@ -511,12 +506,6 @@ ts_telemetry_stats_gather(TelemetryStats *stats)
relmcxt = AllocSetContextCreate(CurrentMemoryContext, "RelationStats", ALLOCSET_DEFAULT_SIZES);
/*
* Use temporary per-tuple memory context to not accumulate cruft during
* processing of pg_class.
*/
oldmcxt = MemoryContextSwitchTo(relmcxt);
while (true)
{
HeapTuple tup;
@ -526,7 +515,6 @@ ts_telemetry_stats_gather(TelemetryStats *stats)
const Hypertable *ht = NULL;
const ContinuousAgg *cagg = NULL;
MemoryContextReset(relmcxt);
tup = systable_getnext(scan);
if (!HeapTupleIsValid(tup))
@ -537,6 +525,13 @@ ts_telemetry_stats_gather(TelemetryStats *stats)
if (should_ignore_relation(catalog, class))
continue;
/*
* Use temporary per-relation memory context to not accumulate cruft
* during processing of pg_class.
*/
oldmcxt = MemoryContextSwitchTo(relmcxt);
MemoryContextReset(relmcxt);
reltype = classify_relation(class, htcache, &ht, &chunk, &cagg);
switch (reltype)
@ -592,9 +587,10 @@ ts_telemetry_stats_gather(TelemetryStats *stats)
case RELTYPE_OTHER:
break;
}
}
MemoryContextSwitchTo(oldmcxt);
}
systable_endscan(scan);
table_close(rel, AccessShareLock);
ts_scan_iterator_close(&statsctx.compressed_chunk_stats_iterator);