From db1b931a4ee885ebd27bb5b335c1e461ccc34bbe Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Fri, 14 Oct 2022 19:06:26 +0200 Subject: [PATCH] libpq: Reset singlerow flag correctly in pipeline mode When a query whose results were requested in single-row mode is the last in the queue by the time those results are being read, the single-row flag was not being reset, because we were returning early from pqPipelineProcessQueue. Move that stanza up so that the flag is always reset at the end of sending that query's results. Add a test for the situation. Backpatch to 14. Author: Denis Laxalde Discussion: https://postgr.es/m/01af18c5-dacc-a8c8-07ee-aecc7650c3e8@dalibo.com --- src/interfaces/libpq/fe-exec.c | 12 ++--- .../modules/libpq_pipeline/libpq_pipeline.c | 45 ++++++++++++++++++- .../libpq_pipeline/traces/singlerow.trace | 20 +++++++++ 3 files changed, 70 insertions(+), 7 deletions(-) diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c index 0274c1b156..64701b562b 100644 --- a/src/interfaces/libpq/fe-exec.c +++ b/src/interfaces/libpq/fe-exec.c @@ -3096,6 +3096,12 @@ pqPipelineProcessQueue(PGconn *conn) break; } + /* + * Reset single-row processing mode. (Client has to set it up for each + * query, if desired.) + */ + conn->singleRowMode = false; + /* * If there are no further commands to process in the queue, get us in * "real idle" mode now. @@ -3115,12 +3121,6 @@ pqPipelineProcessQueue(PGconn *conn) /* Initialize async result-accumulation state */ pqClearAsyncResult(conn); - /* - * Reset single-row processing mode. (Client has to set it up for each - * query, if desired.) - */ - conn->singleRowMode = false; - if (conn->pipelineStatus == PQ_PIPELINE_ABORTED && conn->cmd_queue_head->queryclass != PGQUERY_SYNC) { diff --git a/src/test/modules/libpq_pipeline/libpq_pipeline.c b/src/test/modules/libpq_pipeline/libpq_pipeline.c index c609f42258..a37e4e2500 100644 --- a/src/test/modules/libpq_pipeline/libpq_pipeline.c +++ b/src/test/modules/libpq_pipeline/libpq_pipeline.c @@ -1153,11 +1153,11 @@ test_singlerowmode(PGconn *conn) int i; bool pipeline_ended = false; - /* 1 pipeline, 3 queries in it */ if (PQenterPipelineMode(conn) != 1) pg_fatal("failed to enter pipeline mode: %s", PQerrorMessage(conn)); + /* One series of three commands, using single-row mode for the first two. */ for (i = 0; i < 3; i++) { char *param[1]; @@ -1249,6 +1249,49 @@ test_singlerowmode(PGconn *conn) pg_fatal("didn't get expected terminating TUPLES_OK"); } + /* + * Now issue one command, get its results in with single-row mode, then + * issue another command, and get its results in normal mode; make sure + * the single-row mode flag is reset as expected. + */ + if (PQsendQueryParams(conn, "SELECT generate_series(0, 0)", + 0, NULL, NULL, NULL, NULL, 0) != 1) + pg_fatal("failed to send query: %s", + PQerrorMessage(conn)); + if (PQsendFlushRequest(conn) != 1) + pg_fatal("failed to send flush request"); + if (PQsetSingleRowMode(conn) != 1) + pg_fatal("PQsetSingleRowMode() failed"); + res = PQgetResult(conn); + if (res == NULL) + pg_fatal("unexpected NULL"); + if (PQresultStatus(res) != PGRES_SINGLE_TUPLE) + pg_fatal("Expected PGRES_SINGLE_TUPLE, got %s", + PQresStatus(PQresultStatus(res))); + res = PQgetResult(conn); + if (res == NULL) + pg_fatal("unexpected NULL"); + if (PQresultStatus(res) != PGRES_TUPLES_OK) + pg_fatal("Expected PGRES_TUPLES_OK, got %s", + PQresStatus(PQresultStatus(res))); + if (PQgetResult(conn) != NULL) + pg_fatal("expected NULL result"); + + if (PQsendQueryParams(conn, "SELECT 1", + 0, NULL, NULL, NULL, NULL, 0) != 1) + pg_fatal("failed to send query: %s", + PQerrorMessage(conn)); + if (PQsendFlushRequest(conn) != 1) + pg_fatal("failed to send flush request"); + res = PQgetResult(conn); + if (res == NULL) + pg_fatal("unexpected NULL"); + if (PQresultStatus(res) != PGRES_TUPLES_OK) + pg_fatal("Expected PGRES_TUPLES_OK, got %s", + PQresStatus(PQresultStatus(res))); + if (PQgetResult(conn) != NULL) + pg_fatal("expected NULL result"); + if (PQexitPipelineMode(conn) != 1) pg_fatal("failed to end pipeline mode: %s", PQerrorMessage(conn)); diff --git a/src/test/modules/libpq_pipeline/traces/singlerow.trace b/src/test/modules/libpq_pipeline/traces/singlerow.trace index 9de99befcc..83043e1407 100644 --- a/src/test/modules/libpq_pipeline/traces/singlerow.trace +++ b/src/test/modules/libpq_pipeline/traces/singlerow.trace @@ -36,4 +36,24 @@ B 12 DataRow 1 2 '45' B 12 DataRow 1 2 '46' B 13 CommandComplete "SELECT 5" B 5 ReadyForQuery I +F 36 Parse "" "SELECT generate_series(0, 0)" 0 +F 14 Bind "" "" 0 0 1 0 +F 6 Describe P "" +F 9 Execute "" 0 +F 4 Flush +B 4 ParseComplete +B 4 BindComplete +B 40 RowDescription 1 "generate_series" NNNN 0 NNNN 4 -1 0 +B 11 DataRow 1 1 '0' +B 13 CommandComplete "SELECT 1" +F 16 Parse "" "SELECT 1" 0 +F 14 Bind "" "" 0 0 1 0 +F 6 Describe P "" +F 9 Execute "" 0 +F 4 Flush +B 4 ParseComplete +B 4 BindComplete +B 33 RowDescription 1 "?column?" NNNN 0 NNNN 4 -1 0 +B 11 DataRow 1 1 '1' +B 13 CommandComplete "SELECT 1" F 4 Terminate