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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/interfaces/libpq/libpq-fe.h | |
| 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/interfaces/libpq/libpq-fe.h')
| -rw-r--r-- | src/interfaces/libpq/libpq-fe.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h index c184e853889..c0443d68fdc 100644 --- a/src/interfaces/libpq/libpq-fe.h +++ b/src/interfaces/libpq/libpq-fe.h @@ -112,8 +112,9 @@ typedef enum PGRES_COPY_BOTH, /* Copy In/Out data transfer in progress */ PGRES_SINGLE_TUPLE, /* single tuple from larger resultset */ PGRES_PIPELINE_SYNC, /* pipeline synchronization point */ - PGRES_PIPELINE_ABORTED /* Command didn't run because of an abort + PGRES_PIPELINE_ABORTED, /* Command didn't run because of an abort * earlier in a pipeline */ + PGRES_TUPLES_CHUNK /* chunk of tuples from larger resultset */ } ExecStatusType; typedef enum @@ -489,6 +490,7 @@ extern int PQsendQueryPrepared(PGconn *conn, const int *paramFormats, int resultFormat); extern int PQsetSingleRowMode(PGconn *conn); +extern int PQsetChunkedRowsMode(PGconn *conn, int chunkSize); extern PGresult *PQgetResult(PGconn *conn); /* Routines for managing an asynchronous query */ |