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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2015-05-23 16:24:31 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2015-05-23 16:24:31 -0400 |
| commit | f84c8601d604811a530dadb53ddb52f08639e72b (patch) | |
| tree | d582ce3cd5dbe9613b9c1afa4579588622d5ea3b /src | |
| parent | 72809480d658fbc0654239b2f089991c077c676a (diff) | |
| download | postgresql-f84c8601d604811a530dadb53ddb52f08639e72b.tar.gz postgresql-f84c8601d604811a530dadb53ddb52f08639e72b.zip | |
Add error check for lossy distance functions in index-only scans.
Maybe we should actually support this, but for the moment let's just
throw an error if the opclass tries it.
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/executor/nodeIndexonlyscan.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c index 61bd644ab71..976c77b76c6 100644 --- a/src/backend/executor/nodeIndexonlyscan.c +++ b/src/backend/executor/nodeIndexonlyscan.c @@ -166,6 +166,19 @@ IndexOnlyNext(IndexOnlyScanState *node) } /* + * We don't currently support rechecking ORDER BY distances. (In + * principle, if the index can support retrieval of the originally + * indexed value, it should be able to produce an exact distance + * calculation too. So it's not clear that adding code here for + * recheck/re-sort would be worth the trouble. But we should at least + * throw an error if someone tries it.) + */ + if (scandesc->numberOfOrderBys > 0 && scandesc->xs_recheckorderby) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("lossy distance functions are not supported in index-only scans"))); + + /* * Predicate locks for index-only scans must be acquired at the page * level when the heap is not accessed, since tuple-level predicate * locks need the tuple's xmin value. If we had to visit the tuple |