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| author | Peter Geoghegan <pg@bowt.ie> | 2023-09-28 16:29:27 -0700 |
|---|---|---|
| committer | Peter Geoghegan <pg@bowt.ie> | 2023-09-28 16:29:27 -0700 |
| commit | d4724e94a1ebc5ab5887372b99190d3b112fb06c (patch) | |
| tree | 03500dc1bfb338fd6724a844353296e3c541b08b /src/include | |
| parent | 83ba050f92fa893cfd3f3444319b314f314193de (diff) | |
Fix btmarkpos/btrestrpos array key wraparound bug.
nbtree's mark/restore processing failed to correctly handle an edge case
involving array key advancement and related search-type scan key state.
Scans with ScalarArrayScalarArrayOpExpr quals requiring mark/restore
processing (for a merge join) could incorrectly conclude that an
affected array/scan key must not have advanced during the time between
marking and restoring the scan's position.
As a result of all this, array key handling within btrestrpos could skip
a required call to _bt_preprocess_keys(). This confusion allowed later
primitive index scans to overlook tuples matching the true current array
keys. The scan's search-type scan keys would still have spurious values
corresponding to the final array element(s) -- not values matching the
first/now-current array element(s).
To fix, remember that "array key wraparound" has taken place during the
ongoing btrescan in a flag variable stored in the scan's state, and use
that information at the point where btrestrpos decides if another call
to _bt_preprocess_keys is required.
Oversight in commit 70bc5833, which taught nbtree to handle array keys
during mark/restore processing, but missed this subtlety. That commit
was itself a bug fix for an issue in commit 9e8da0f7, which taught
nbtree to handle ScalarArrayOpExpr quals natively.
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WzkgP3DDRJxw6DgjCxo-cu-DKrvjEv_ArkP2ctBJatDCYg@mail.gmail.com
Backpatch: 11- (all supported branches).
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/access/nbtree.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h index 79506c748b2..7a0124b48b0 100644 --- a/src/include/access/nbtree.h +++ b/src/include/access/nbtree.h @@ -903,8 +903,10 @@ typedef struct BTArrayKeyInfo typedef struct BTScanOpaqueData { - /* these fields are set by _bt_preprocess_keys(): */ + /* all fields (except arraysStarted) are set by _bt_preprocess_keys(): */ bool qual_ok; /* false if qual can never be satisfied */ + bool arraysStarted; /* Started array keys, but have yet to "reach + * past the end" of all arrays? */ int numberOfKeys; /* number of preprocessed scan keys */ ScanKey keyData; /* array of preprocessed scan keys */ |