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| author | Tom Lane | 2024-04-07 00:41:32 +0000 |
|---|---|---|
| committer | Tom Lane | 2024-04-07 00:45:11 +0000 |
| commit | 4643a2b265e967cc5f13ffa0c7c6912dbb3466d0 (patch) | |
| tree | ae3c3e182c5e0586dcecd93f0957deb2d0416b68 /src/backend/replication | |
| parent | 92641d8d651e685b49a6e2842d306aa5fe7ba500 (diff) | |
Support retrieval of results in chunks with libpq.
This patch generalizes libpq's existing single-row mode to allow
individual partial-result PGresults to contain up to N rows, rather
than always one row. This reduces malloc overhead compared to plain
single-row mode, and it is very useful for psql's FETCH_COUNT feature,
since otherwise we'd have to add code (and cycles) to either merge
single-row PGresults into a bigger one or teach psql's
results-printing logic to accept arrays of PGresults.
To avoid API breakage, PQsetSingleRowMode() remains the same, and we
add a new function PQsetChunkedRowsMode() to invoke the more general
case. Also, PGresults obtained the old way continue to carry the
PGRES_SINGLE_TUPLE status code, while if PQsetChunkedRowsMode() is
used then their status code is PGRES_TUPLES_CHUNK. The underlying
logic is the same either way, though.
Daniel Vérité, reviewed by Laurenz Albe and myself (and whacked
around a bit by me, so any remaining bugs are my fault)
Discussion: https://postgr.es/m/CAKZiRmxsVTkO928CM+-ADvsMyePmU3L9DQCa9NwqjvLPcEe5QA@mail.gmail.com
Diffstat (limited to 'src/backend/replication')
| -rw-r--r-- | src/backend/replication/libpqwalreceiver/libpqwalreceiver.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c index 761bf0f677c..3c2b1bb4966 100644 --- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c +++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c @@ -1248,8 +1248,9 @@ libpqrcv_exec(WalReceiverConn *conn, const char *query, switch (PQresultStatus(pgres)) { - case PGRES_SINGLE_TUPLE: case PGRES_TUPLES_OK: + case PGRES_SINGLE_TUPLE: + case PGRES_TUPLES_CHUNK: walres->status = WALRCV_OK_TUPLES; libpqrcv_processTuples(pgres, walres, nRetTypes, retTypes); break; |