diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index c3bd4f9..366f278 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -4656,6 +4656,526 @@ int PQflush(PGconn *conn);
+
+ Batch mode and query pipelining
+
+
+ libpq
+ batch mode
+
+
+
+ libpq
+ pipelining
+
+
+
+ libpq supports queueing up queries into
+ a pipeline to be executed as a batch on the server. Batching queries allows
+ applications to avoid a client/server round-trip after each query to get
+ the results before issuing the next query.
+
+
+
+ An example of batch use may be found in the source distribution in
+ src/test/modules/test_libpq/testlibpqbatch.c.
+
+
+
+ When to use batching
+
+
+ Much like asynchronous query mode, there is no performance disadvantage to
+ using batching and pipelining. It increases client application complexity
+ and extra caution is required to prevent client/server deadlocks but
+ can sometimes offer considerable performance improvements.
+
+
+
+ Batching is most useful when the server is distant, i.e. network latency
+ (ping time) is high, and when many small operations are being performed in
+ rapid sequence. There is usually less benefit in using batches when each
+ query takes many multiples of the client/server round-trip time to execute.
+ A 100-statement operation run on a server 300ms round-trip-time away would take
+ 30 seconds in network latency alone without batching; with batching it may spend
+ as little as 0.3s waiting for results from the server.
+
+
+
+ Use batches when your application does lots of small
+ INSERT, UPDATE and
+ DELETE operations that can't easily be transformed into
+ operations on sets or into a
+ COPY operation.
+
+
+
+ Batching is less useful when information from one operation is required by the
+ client before it knows enough to send the next operation. The client must
+ introduce a synchronisation point and wait for a full client/server
+ round-trip to get the results it needs. However, it's often possible to
+ adjust the client design to exchange the required information server-side.
+ Read-modify-write cycles are especially good candidates; for example:
+
+ BEGIN;
+ SELECT x FROM mytable WHERE id = 42 FOR UPDATE;
+ -- result: x=2
+ -- client adds 1 to x:
+ UPDATE mytable SET x = 3 WHERE id = 42;
+ COMMIT;
+
+ could be much more efficiently done with:
+
+ UPDATE mytable SET x = x + 1 WHERE id = 42;
+
+
+
+
+
+ The batch API was introduced in PostgreSQL 10.0, but clients using PostgresSQL 10.0 version of libpq can
+ use batches on server versions 8.4 and newer. Batching works on any server
+ that supports the v3 extended query protocol.
+
+
+
+
+
+
+ Using batch mode
+
+
+ To issue batches the application must switch
+ a connection into batch mode. Enter batch mode with PQenterBatchMode(conn) or test
+ whether batch mode is active with PQbatchStatus(conn). In batch mode only asynchronous operations are permitted, and
+ COPY is not recommended as it most likely will trigger failure in batch processing.
+ Using any synchronous command execution functions such as PQfn,
+ PQexec or one of its sibling functions are error conditions.
+ Functions allowed in batch mode are described in .
+
+
+
+ The client uses libpq's asynchronous query functions to dispatch work,
+ marking the end of each batch with PQbatchSyncQueue.
+ And to get results, it uses PQgetResult and
+ PQbatchProcessQueue. It may eventually exit
+ batch mode with PQexitBatchMode once all results are
+ processed.
+
+
+
+
+ It is best to use batch mode with libpq in
+ non-blocking mode. If used in
+ blocking mode it is possible for a client/server deadlock to occur. The
+ client will block trying to send queries to the server, but the server will
+ block trying to send results from queries it has already processed to the
+ client. This only occurs when the client sends enough queries to fill its
+ output buffer and the server's receive buffer before switching to
+ processing input from the server, but it's hard to predict exactly when
+ that'll happen so it's best to always use non-blocking mode.
+
+
+
+
+ Issuing queries
+
+
+ After entering batch mode the application dispatches requests
+ using normal asynchronous libpq functions such as
+ PQsendQueryParams, PQsendPrepare,
+ PQsendQueryPrepared, PQsendDescribePortal,
+ PQsendDescribePrepared.
+ The asynchronous requests are followed by a PQbatchSyncQueue(conn) call to mark
+ the end of the batch. The client does not need to call
+ PQgetResult immediately after dispatching each
+ operation. Result processing
+ is handled separately.
+
+
+
+ Batched operations will be executed by the server in the order the client
+ sends them. The server will send the results in the order the statements
+ executed. The server may begin executing the batch before all commands
+ in the batch are queued and the end of batch command is sent. If any
+ statement encounters an error the server aborts the current transaction and
+ skips processing the rest of the batch. Query processing resumes after the
+ end of the failed batch.
+
+
+
+ It's fine for one operation to depend on the results of a
+ prior one. One query may define a table that the next query in the same
+ batch uses; similarly, an application may create a named prepared statement
+ then execute it with later statements in the same batch.
+
+
+
+
+
+ Processing results
+
+
+ The client interleaves result
+ processing with sending batch queries, or for small batches may
+ process all results after sending the whole batch.
+
+
+
+ To get the result of the first batch entry the client must call PQbatchProcessQueue. It must then call
+ PQgetResult and handle the results until
+ PQgetResult returns null. The result from the next batch entry
+ may then be retrieved using PQbatchProcessQueue and the cycle repeated. The
+ application handles individual statement results as normal.
+
+
+
+ To enter single-row mode, call PQsetSingleRowMode immediately after a
+ successful call of PQbatchProcessQueue. This mode selection is effective
+ only for the query currently being processed. For more information on the use of PQsetSingleRowMode
+ , refer to .
+
+
+
+
+ PQgetResult behaves the same as for normal asynchronous
+ processing except that it may contain the new PGresult types
+ PGRES_BATCH_END and PGRES_BATCH_ABORTED.
+ PGRES_BATCH_END is reported exactly once for each
+ PQbatchSyncQueue call at the corresponding point in
+ the result stream and at no other time. PGRES_BATCH_ABORTED
+ is emitted during error handling; see
+ error handling.
+
+
+
+ PQisBusy, PQconsumeInput, etc
+ operate as normal when processing batch results.
+
+
+
+ libpq does not provide any information to the
+ application about the query currently being processed. The application
+ must keep track of the order in which it sent queries and the expected
+ results. Applications will typically use a state machine or a FIFO queue
+ for this.
+
+
+
+
+
+ Error handling
+
+
+ When a query in a batch causes an ERROR the server
+ skips processing all subsequent messages until the end-of-batch message.
+ The open transaction is aborted.
+
+
+
+ From the client perspective, after the client gets a
+ PGRES_FATAL_ERROR return from
+ PQresultStatus the batch is flagged as aborted.
+ libpq will report
+ PGRES_BATCH_ABORTED result for each remaining queued
+ operation in an aborted batch. The result for
+ PQbatchSyncQueue is reported as
+ PGRES_BATCH_END to signal the end of the aborted batch
+ and resumption of normal result processing.
+
+
+
+ The client must process results with
+ PQbatchProcessQueue(...) and
+ PQgetResult during error recovery.
+
+
+
+ If the batch used an implicit transaction then operations that have
+ already executed are rolled back and operations that were queued for after
+ the failed operation are skipped entirely. The same behaviour holds if the
+ batch starts and commits a single explicit transaction (i.e. the first
+ statement is BEGIN and the last is
+ COMMIT) except that the session remains in an aborted
+ transaction state at the end of the batch. If a batch contains
+ multiple explicit transactions, all transactions that committed
+ prior to the error remain committed, the currently in-progress transaction
+ is aborted and all subsequent operations in the current and all later
+ transactions in the same batch are skipped completely.
+
+
+
+
+ The client must not assume that work is committed when it
+ sends a COMMIT, only when the
+ corresponding result is received to confirm the commit is complete.
+ Because errors arrive asynchronously the application needs to be able to
+ restart from the last received committed change and
+ resend work done after that point if something goes wrong.
+
+
+
+
+
+
+ Interleaving result processing and query dispatch
+
+
+ To avoid deadlocks on large batches the client should be structured around
+ a nonblocking I/O loop using a function like select,
+ poll, epoll,
+ WaitForMultipleObjectEx, etc.
+
+
+
+ The client application should generally maintain a queue of work still to
+ be dispatched and a queue of work that has been dispatched but not yet had
+ its results processed. When the socket is writable it should dispatch more
+ work. When the socket is readable it should read results and process them,
+ matching them up to the next entry in its expected results queue. Batches
+ should be scoped to logical units of work, usually (but not always) one
+ transaction per batch. There's no need to exit batch mode and re-enter it
+ between batches or to wait for one batch to finish before sending the next.
+
+
+
+ An example using select() and a simple state machine
+ to track sent and received work is in
+ src/test/modules/test_libpq/testlibpqbatch.c in the PostgreSQL
+ source distribution.
+
+
+
+
+
+ Ending batch mode
+
+
+ Once all dispatched commands have had their results processed and the end batch
+ result has been consumed the application may return to non-batched mode with
+ PQexitBatchMode(conn).
+
+
+
+
+
+
+ Functions associated with batch mode
+
+
+
+
+
+ PQbatchStatus
+
+ PQbatchStatus
+
+
+
+
+
+ Returns current batch mode status of the libpq connection.
+
+int PQbatchStatus(PGconn *conn);
+
+
+
+
+
+ PQBATCH_MODE_ON
+
+
+
+
+ Returns PQBATCH_MODE_ON if libpq connection is in batch mode.
+
+
+
+
+
+
+ PQBATCH_MODE_OFF
+
+
+
+
+ Returns PQBATCH_MODE_OFF if libpq connection is not in batch mode.
+
+
+
+
+
+
+ PQBATCH_MODE_ABORTED
+
+
+
+ Returns PQBATCH_MODE_ABORTED if libpq connection is in
+ aborted status. The aborted flag is cleared as soon as the result of the
+ PQbatchSyncQueue at the end of the aborted batch is
+ processed. Clients don't usually need this function to verify aborted status
+ as they can tell that the batch is aborted from PGRES_BATCH_ABORTED
+ result codes.
+
+
+
+
+
+
+
+
+
+
+
+ PQenterBatchMode
+
+ PQenterBatchMode
+
+
+
+
+
+ Causes a connection to enter batch mode if it is currently idle or
+ already in batch mode.
+
+
+int PQenterBatchMode(PGconn *conn);
+
+
+
+
+ Returns 1 for success. Returns 0 and has no
+ effect if the connection is not currently idle, i.e. it has a result
+ ready, is waiting for more input from the server, etc. This function
+ does not actually send anything to the server, it just changes the
+ libpq connection state.
+
+
+
+
+
+
+
+ PQexitBatchMode
+
+ PQexitBatchMode
+
+
+
+
+
+ Causes a connection to exit batch mode if it is currently in batch mode
+ with an empty queue and no pending results.
+
+int PQexitBatchMode(PGconn *conn);
+
+
+ Returns 1 for success.
+ Returns 1 and takes no action if not in batch mode. If the connection has
+ pending batch items in the queue for reading with
+ PQbatchProcessQueue, the current statement isn't finished
+ processing or there are results pending for collection with
+ PQgetResult, returns 0 and does nothing.
+
+
+
+
+
+
+
+ PQbatchSyncQueue
+
+ PQbatchSyncQueue
+
+
+
+
+
+ Delimits the end of a set of a batched commands by sending a sync message and flushing
+ the send buffer. The end of a batch serves as
+ the delimiter of an implicit transaction and
+ an error recovery point; see
+ error handling.
+
+
+int PQbatchSyncQueue(PGconn *conn);
+
+
+ Returns 1 for success. Returns 0 if the connection is not in batch mode
+ or sending a sync message is failed.
+
+
+
+
+
+
+
+ PQbatchProcessQueue
+
+ PQbatchProcessQueue
+
+
+
+
+
+ Causes the connection to start processing the next queued query's
+ results.
+
+
+
+int PQbatchProcessQueue(PGconn *conn);
+
+
+
+ Returns 1 if a new query was popped from the result queue
+ for processing. Returns 0 and has no effect if there are no query results
+ pending, batch mode is not enabled, or if the query currently processed
+ is incomplete or still has pending results. Reason for these failures can
+ be verified with PQbatchQueueCount, PQbatchStatus
+ and PQgetResult.
+ See processing results.
+
+
+
+
+
+
+
+ PQbatchQueueCount
+
+ PQbatchQueueCount
+
+
+
+
+
+ Returns the number of queries still in the queue for this batch, not
+ including any query that's currently having results being processed.
+ This is the number of times PQbatchProcessQueue has to be
+ called before the query queue is empty again.
+
+
+int PQbatchQueueCount(PGconn *conn);
+
+
+
+
+
+
+
+
+
+
+
+
+
Retrieving Query Results Row-By-Row
@@ -4696,6 +5216,14 @@ int PQflush(PGconn *conn);
Each object should be freed with PQclear as usual.
+
+
+ On using batch mode, call PQsetSingleRowMode
+ immediately after a successful call of PQbatchProcessQueue
+ See for more information.
+
+
+
diff --git a/doc/src/sgml/lobj.sgml b/doc/src/sgml/lobj.sgml
index 7757e1e..db8523d 100644
--- a/doc/src/sgml/lobj.sgml
+++ b/doc/src/sgml/lobj.sgml
@@ -130,6 +130,10 @@
libpq library.
+
+ Client applications cannot use these functions while libpq connection is in batch mode.
+
+
Creating a Large Object
diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index f6fa0e4..d4ee576 100644
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -936,6 +936,9 @@ libpqrcv_exec(WalReceiverConn *conn, const char *query,
walres->status = WALRCV_ERROR;
walres->err = pchomp(PQerrorMessage(conn->streamConn));
break;
+ default:
+ /* This is just to keep compiler quiet */
+ break;
}
PQclear(pgres);
diff --git a/src/interfaces/libpq/exports.txt b/src/interfaces/libpq/exports.txt
index d6a38d0..49871f5 100644
--- a/src/interfaces/libpq/exports.txt
+++ b/src/interfaces/libpq/exports.txt
@@ -172,3 +172,9 @@ PQsslAttribute 169
PQsetErrorContextVisibility 170
PQresultVerboseErrorMessage 171
PQencryptPasswordConn 172
+PQbatchQueueCount 173
+PQenterBatchMode 174
+PQexitBatchMode 175
+PQbatchSyncQueue 176
+PQbatchProcessQueue 177
+PQbatchStatus 178
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 02ec8f0..a92f4bc 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -3483,6 +3483,25 @@ sendTerminateConn(PGconn *conn)
}
/*
+ * PQfreeCommandQueue
+ * Free all the entries of PGcommandQueueEntry queue passed.
+ */
+static void
+PQfreeCommandQueue(PGcommandQueueEntry *queue)
+{
+
+ while (queue != NULL)
+ {
+ PGcommandQueueEntry *prev = queue;
+
+ queue = queue->next;
+ if (prev->query)
+ free(prev->query);
+ free(prev);
+ }
+}
+
+/*
* closePGconn
* - properly close a connection to the backend
*
@@ -3494,6 +3513,7 @@ static void
closePGconn(PGconn *conn)
{
PGnotify *notify;
+ PGcommandQueueEntry *queue;
pgParameterStatus *pstatus;
sendTerminateConn(conn);
@@ -3526,6 +3546,14 @@ closePGconn(PGconn *conn)
free(prev);
}
conn->notifyHead = conn->notifyTail = NULL;
+ queue = conn->cmd_queue_head;
+ PQfreeCommandQueue(queue);
+ conn->cmd_queue_head = conn->cmd_queue_tail = NULL;
+
+ queue = conn->cmd_queue_recycle;
+ PQfreeCommandQueue(queue);
+
+ conn->cmd_queue_recycle = NULL;
pstatus = conn->pstatus;
while (pstatus != NULL)
{
diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index 9decd53..2a3928b 100644
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -39,7 +39,9 @@ char *const pgresStatus[] = {
"PGRES_NONFATAL_ERROR",
"PGRES_FATAL_ERROR",
"PGRES_COPY_BOTH",
- "PGRES_SINGLE_TUPLE"
+ "PGRES_SINGLE_TUPLE",
+ "PGRES_BATCH_END",
+ "PGRES_BATCH_ABORTED"
};
/*
@@ -69,6 +71,9 @@ static PGresult *PQexecFinish(PGconn *conn);
static int PQsendDescribe(PGconn *conn, char desc_type,
const char *desc_target);
static int check_field_number(const PGresult *res, int field_num);
+static PGcommandQueueEntry *PQmakePipelinedCommand(PGconn *conn);
+static void PQappendPipelinedCommand(PGconn *conn, PGcommandQueueEntry * entry);
+static void PQrecyclePipelinedCommand(PGconn *conn, PGcommandQueueEntry * entry);
/* ----------------
@@ -1108,7 +1113,7 @@ pqRowProcessor(PGconn *conn, const char **errmsgp)
conn->next_result = conn->result;
conn->result = res;
/* And mark the result ready to return */
- conn->asyncStatus = PGASYNC_READY;
+ conn->asyncStatus = PGASYNC_READY_MORE;
}
return 1;
@@ -1131,6 +1136,13 @@ fail:
int
PQsendQuery(PGconn *conn, const char *query)
{
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("cannot PQsendQuery in batch mode, use PQsendQueryParams\n"));
+ return false;
+ }
+
if (!PQsendQueryStart(conn))
return 0;
@@ -1229,6 +1241,10 @@ PQsendPrepare(PGconn *conn,
const char *stmtName, const char *query,
int nParams, const Oid *paramTypes)
{
+ PGcommandQueueEntry *pipeCmd = NULL;
+ char **last_query;
+ PGQueryClass *queryclass;
+
if (!PQsendQueryStart(conn))
return 0;
@@ -1287,18 +1303,34 @@ PQsendPrepare(PGconn *conn,
goto sendFailed;
/* construct the Sync message */
- if (pqPutMsgStart('S', false, conn) < 0 ||
- pqPutMsgEnd(conn) < 0)
- goto sendFailed;
+ if (conn->batch_status == PQBATCH_MODE_OFF)
+ {
+ if (pqPutMsgStart('S', false, conn) < 0 ||
+ pqPutMsgEnd(conn) < 0)
+ goto sendFailed;
+
+ last_query = &conn->last_query;
+ queryclass = &conn->queryclass;
+ }
+ else
+ {
+ pipeCmd = PQmakePipelinedCommand(conn);
+
+ if (pipeCmd == NULL)
+ return 0; /* error msg already set */
+
+ last_query = &pipeCmd->query;
+ queryclass = &pipeCmd->queryclass;
+ }
/* remember we are doing just a Parse */
- conn->queryclass = PGQUERY_PREPARE;
+ *queryclass = PGQUERY_PREPARE;
/* and remember the query text too, if possible */
/* if insufficient memory, last_query just winds up NULL */
- if (conn->last_query)
- free(conn->last_query);
- conn->last_query = strdup(query);
+ if (*last_query)
+ free(*last_query);
+ *last_query = strdup(query);
/*
* Give the data a push. In nonblock mode, don't complain if we're unable
@@ -1308,10 +1340,14 @@ PQsendPrepare(PGconn *conn,
goto sendFailed;
/* OK, it's launched! */
- conn->asyncStatus = PGASYNC_BUSY;
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ PQappendPipelinedCommand(conn, pipeCmd);
+ else
+ conn->asyncStatus = PGASYNC_BUSY;
return 1;
sendFailed:
+ PQrecyclePipelinedCommand(conn, pipeCmd);
pqHandleSendFailure(conn);
return 0;
}
@@ -1359,7 +1395,80 @@ PQsendQueryPrepared(PGconn *conn,
}
/*
- * Common startup code for PQsendQuery and sibling routines
+ * PQmakePipelinedCommand
+ * Get a new command queue entry, allocating it if required. Doesn't add it to
+ * the tail of the queue yet, use PQappendPipelinedCommand once the command has
+ * been written for that. If a command fails once it's called this, it should
+ * use PQrecyclePipelinedCommand to put it on the freelist or release it.
+ *
+ * If allocation fails sets the error message and returns null.
+ */
+static PGcommandQueueEntry *
+PQmakePipelinedCommand(PGconn *conn)
+{
+ PGcommandQueueEntry *entry;
+
+ if (conn->cmd_queue_recycle == NULL)
+ {
+ entry = (PGcommandQueueEntry *) malloc(sizeof(PGcommandQueueEntry));
+ if (entry == NULL)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("out of memory\n"));
+ return NULL;
+ }
+ }
+ else
+ {
+ entry = conn->cmd_queue_recycle;
+ conn->cmd_queue_recycle = entry->next;
+ }
+ entry->next = NULL;
+ entry->query = NULL;
+
+ return entry;
+}
+
+/*
+ * PQappendPipelinedCommand
+ * Append a precreated command queue entry to the queue after it's been
+ * sent successfully.
+ */
+static void
+PQappendPipelinedCommand(PGconn *conn, PGcommandQueueEntry * entry)
+{
+ if (conn->cmd_queue_head == NULL)
+ conn->cmd_queue_head = entry;
+ else
+ conn->cmd_queue_tail->next = entry;
+ conn->cmd_queue_tail = entry;
+}
+
+/*
+ * PQrecyclePipelinedCommand
+ * Push a command queue entry onto the freelist. It must be a dangling entry
+ * with null next pointer and not referenced by any other entry's next pointer.
+ */
+static void
+PQrecyclePipelinedCommand(PGconn *conn, PGcommandQueueEntry * entry)
+{
+ if (entry == NULL)
+ return;
+ if (entry->next != NULL)
+ {
+ fprintf(stderr, libpq_gettext("tried to recycle non-dangling command queue entry"));
+ abort();
+ }
+ if (entry->query)
+ free(entry->query);
+
+ entry->next = conn->cmd_queue_recycle;
+ conn->cmd_queue_recycle = entry;
+}
+
+/*
+ * PQsendQueryStart
+ * Common startup code for PQsendQuery and sibling routines
*/
static bool
PQsendQueryStart(PGconn *conn)
@@ -1377,20 +1486,60 @@ PQsendQueryStart(PGconn *conn)
libpq_gettext("no connection to the server\n"));
return false;
}
- /* Can't send while already busy, either. */
- if (conn->asyncStatus != PGASYNC_IDLE)
+
+ /* Can't send while already busy, either, unless enqueuing for later */
+ if (conn->asyncStatus != PGASYNC_IDLE && conn->batch_status == PQBATCH_MODE_OFF)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("another command is already in progress\n"));
return false;
}
- /* initialize async result-accumulation state */
- pqClearAsyncResult(conn);
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ /*
+ * When enqueuing a message we don't change much of the connection
+ * state since it's already in use for the current command. The
+ * connection state will get updated when PQbatchQueueProcess(...)
+ * advances to start processing the queued message.
+ *
+ * Just make sure we can safely enqueue given the current connection
+ * state. We can enqueue behind another queue item, or behind a
+ * non-queue command (one that sends its own sync), but we can't
+ * enqueue if the connection is in a copy state.
+ */
+ switch (conn->asyncStatus)
+ {
+ case PGASYNC_QUEUED:
+ case PGASYNC_READY:
+ case PGASYNC_READY_MORE:
+ case PGASYNC_BUSY:
+ /* ok to queue */
+ break;
+ case PGASYNC_COPY_IN:
+ case PGASYNC_COPY_OUT:
+ case PGASYNC_COPY_BOTH:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("cannot queue commands during COPY\n"));
+ return false;
+ break;
+ case PGASYNC_IDLE:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext_noop("internal error, idle state in batch mode"));
+ break;
+ }
+ }
+ else
+ {
+ /* This command's results will come in immediately.
+ * Initialize async result-accumulation state
+ */
+ pqClearAsyncResult(conn);
- /* reset single-row processing mode */
- conn->singleRowMode = false;
+ /* reset single-row processing mode */
+ conn->singleRowMode = false;
+ }
/* ready to send command message */
return true;
}
@@ -1414,6 +1563,10 @@ PQsendQueryGuts(PGconn *conn,
int resultFormat)
{
int i;
+ PGcommandQueueEntry *pipeCmd = NULL;
+ char **last_query;
+ PGQueryClass *queryclass;
+
/* This isn't gonna work on a 2.0 server */
if (PG_PROTOCOL_MAJOR(conn->pversion) < 3)
@@ -1423,6 +1576,23 @@ PQsendQueryGuts(PGconn *conn,
return 0;
}
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ pipeCmd = PQmakePipelinedCommand(conn);
+
+ if (pipeCmd == NULL)
+ return 0; /* error msg already set */
+
+ last_query = &pipeCmd->query;
+ queryclass = &pipeCmd->queryclass;
+ }
+ else
+ {
+ last_query = &conn->last_query;
+ queryclass = &conn->queryclass;
+ }
+
+
/*
* We will send Parse (if needed), Bind, Describe Portal, Execute, Sync,
* using specified statement name and the unnamed portal.
@@ -1535,22 +1705,25 @@ PQsendQueryGuts(PGconn *conn,
pqPutMsgEnd(conn) < 0)
goto sendFailed;
- /* construct the Sync message */
- if (pqPutMsgStart('S', false, conn) < 0 ||
- pqPutMsgEnd(conn) < 0)
- goto sendFailed;
+ if (conn->batch_status == PQBATCH_MODE_OFF)
+ {
+ /* construct the Sync message */
+ if (pqPutMsgStart('S', false, conn) < 0 ||
+ pqPutMsgEnd(conn) < 0)
+ goto sendFailed;
+ }
/* remember we are using extended query protocol */
- conn->queryclass = PGQUERY_EXTENDED;
+ *queryclass = PGQUERY_EXTENDED;
/* and remember the query text too, if possible */
/* if insufficient memory, last_query just winds up NULL */
- if (conn->last_query)
- free(conn->last_query);
+ if (*last_query)
+ free(*last_query);
if (command)
- conn->last_query = strdup(command);
+ *last_query = strdup(command);
else
- conn->last_query = NULL;
+ *last_query = NULL;
/*
* Give the data a push. In nonblock mode, don't complain if we're unable
@@ -1560,10 +1733,14 @@ PQsendQueryGuts(PGconn *conn,
goto sendFailed;
/* OK, it's launched! */
- conn->asyncStatus = PGASYNC_BUSY;
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ PQappendPipelinedCommand(conn, pipeCmd);
+ else
+ conn->asyncStatus = PGASYNC_BUSY;
return 1;
sendFailed:
+ PQrecyclePipelinedCommand(conn, pipeCmd);
pqHandleSendFailure(conn);
return 0;
}
@@ -1690,6 +1867,302 @@ PQisBusy(PGconn *conn)
return conn->asyncStatus == PGASYNC_BUSY;
}
+/*
+ * PQbatchQueueCount
+ * Return number of queries currently pending in batch mode
+ */
+int
+PQbatchQueueCount(PGconn *conn)
+{
+ int count = 0;
+ PGcommandQueueEntry *entry;
+
+ if (PQbatchStatus(conn) == PQBATCH_MODE_OFF)
+ return 0;
+
+ entry = conn->cmd_queue_head;
+ while (entry != NULL)
+ {
+ ++count;
+ entry = entry->next;
+ }
+ return count;
+}
+
+/*
+ * PQbatchStatus
+ * Returns current batch mode status
+ */
+int
+PQbatchStatus(PGconn *conn)
+{
+ if (!conn)
+ return FALSE;
+
+ return conn->batch_status;
+}
+
+/*
+ * PQbatchBegin
+ * Put an idle connection in batch mode. Commands submitted after this
+ * can be pipelined on the connection, there's no requirement to wait for
+ * one to finish before the next is dispatched.
+ *
+ * Queuing of new query or syncing during COPY is not allowed.
+ *
+ * A set of commands is terminated by a PQbatchQueueSync. Multiple sets of batched
+ * commands may be sent while in batch mode. Batch mode can be exited by
+ * calling PQbatchEnd() once all results are processed.
+ *
+ * This doesn't actually send anything on the wire, it just puts libpq
+ * into a state where it can pipeline work.
+ */
+int
+PQenterBatchMode(PGconn *conn)
+{
+ if (!conn)
+ return false;
+
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ return true;
+
+ if (conn->asyncStatus != PGASYNC_IDLE)
+ return false;
+
+ conn->batch_status = PQBATCH_MODE_ON;
+ conn->asyncStatus = PGASYNC_QUEUED;
+
+ return true;
+}
+
+/*
+ * PQbatchEnd
+ * End batch mode and return to normal command mode.
+ *
+ * Has no effect unless the client has processed all results
+ * from all outstanding batches and the connection is idle.
+ *
+ * Returns true if batch mode ended.
+ */
+int
+PQexitBatchMode(PGconn *conn)
+{
+ if (!conn)
+ return false;
+
+ if (conn->batch_status == PQBATCH_MODE_OFF)
+ return true;
+
+ switch (conn->asyncStatus)
+ {
+ case PGASYNC_IDLE:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext_noop("internal error, IDLE in batch mode"));
+ break;
+ case PGASYNC_COPY_IN:
+ case PGASYNC_COPY_OUT:
+ case PGASYNC_COPY_BOTH:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext_noop("internal error, COPY in batch mode"));
+ break;
+ case PGASYNC_READY:
+ case PGASYNC_READY_MORE:
+ case PGASYNC_BUSY:
+ /* can't end batch while busy */
+ return false;
+ case PGASYNC_QUEUED:
+ break;
+ }
+
+ /* still work to process */
+ if (conn->cmd_queue_head != NULL)
+ return false;
+
+ conn->batch_status = PQBATCH_MODE_OFF;
+ conn->asyncStatus = PGASYNC_IDLE;
+
+ return true;
+}
+
+/*
+ * PQbatchQueueSync
+ * End a batch submission by sending a protocol sync. The connection will
+ * remain in batch mode and unavailable for new non-batch commands until all
+ * results from the batch are processed by the client.
+ *
+ * It's legal to start submitting another batch immediately, without waiting
+ * for the results of the current batch. There's no need to end batch mode
+ * and start it again.
+ *
+ * If a command in a batch fails, every subsequent command up to and including
+ * the PQbatchQueueSync command result gets set to PGRES_BATCH_ABORTED state. If the
+ * whole batch is processed without error, a PGresult with PGRES_BATCH_END is
+ * produced.
+ */
+int
+PQbatchSyncQueue(PGconn *conn)
+{
+ PGcommandQueueEntry *entry;
+
+ if (!conn)
+ return false;
+
+ if (conn->batch_status == PQBATCH_MODE_OFF)
+ return false;
+
+ switch (conn->asyncStatus)
+ {
+ case PGASYNC_IDLE:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext_noop("internal error, IDLE in batch mode"));
+ break;
+ case PGASYNC_COPY_IN:
+ case PGASYNC_COPY_OUT:
+ case PGASYNC_COPY_BOTH:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext_noop("internal error, COPY in batch mode"));
+ break;
+ case PGASYNC_READY:
+ case PGASYNC_READY_MORE:
+ case PGASYNC_BUSY:
+ case PGASYNC_QUEUED:
+ /* can send sync to end this batch of cmds */
+ break;
+ }
+
+ entry = PQmakePipelinedCommand(conn);
+ if (entry == NULL)
+ return false; /* error msg already set */
+
+ entry->queryclass = PGQUERY_SYNC;
+ entry->query = NULL;
+
+ /* construct the Sync message */
+ if (pqPutMsgStart('S', false, conn) < 0 ||
+ pqPutMsgEnd(conn) < 0)
+ goto sendFailed;
+
+ PQappendPipelinedCommand(conn, entry);
+
+ /*
+ * Give the data a push. In nonblock mode, don't complain if we're unable
+ * to send it all; PQgetResult() will do any additional flushing needed.
+ */
+ if (PQflush(conn) < 0)
+ goto sendFailed;
+
+ return true;
+
+sendFailed:
+ PQrecyclePipelinedCommand(conn, entry);
+ pqHandleSendFailure(conn);
+ return false;
+}
+
+/*
+ * PQbatchQueueProcess
+ * In batch mode, start processing the next query in the queue.
+ *
+ * Returns true if the next query was popped from the queue and can
+ * be processed by PQconsumeInput, PQgetResult, etc.
+ *
+ * Returns false if the current query isn't done yet, the connection
+ * is not in a batch, or there are no more queries to process.
+ */
+int
+PQbatchProcessQueue(PGconn *conn)
+{
+ PGcommandQueueEntry *next_query;
+
+ if (!conn)
+ return false;
+
+ if (conn->batch_status == PQBATCH_MODE_OFF)
+ return false;
+
+ switch (conn->asyncStatus)
+ {
+ case PGASYNC_COPY_IN:
+ case PGASYNC_COPY_OUT:
+ case PGASYNC_COPY_BOTH:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext_noop("internal error, COPY in batch mode"));
+ break;
+ case PGASYNC_READY:
+ case PGASYNC_READY_MORE:
+ case PGASYNC_BUSY:
+ /* client still has to process current query or results */
+ return false;
+ break;
+ case PGASYNC_IDLE:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext_noop("internal error, IDLE in batch mode"));
+ break;
+ case PGASYNC_QUEUED:
+ /* next query please */
+ break;
+ }
+
+ if (conn->cmd_queue_head == NULL)
+ {
+ /*
+ * In batch mode but nothing left on the queue; caller can submit more
+ * work or PQbatchEnd() now.
+ */
+ return false;
+ }
+
+ /*
+ * Pop the next query from the queue and set up the connection state as if
+ * it'd just been dispatched from a non-batched call
+ */
+ next_query = conn->cmd_queue_head;
+ conn->cmd_queue_head = next_query->next;
+ next_query->next = NULL;
+
+ /* This command's results will come in immediately.
+ * Initialize async result-accumulation state */
+ pqClearAsyncResult(conn);
+
+ /* reset single-row processing mode */
+ conn->singleRowMode = false;
+
+
+ conn->last_query = next_query->query;
+ next_query->query = NULL;
+ conn->queryclass = next_query->queryclass;
+
+ PQrecyclePipelinedCommand(conn, next_query);
+
+ if (conn->batch_status == PQBATCH_MODE_ABORTED && conn->queryclass != PGQUERY_SYNC)
+ {
+ /*
+ * In an aborted batch we don't get anything from the server for each
+ * result; we're just discarding input until we get to the next sync
+ * from the server. The client needs to know its queries got aborted
+ * so we create a fake PGresult to return immediately from
+ * PQgetResult.
+ */
+ conn->result = PQmakeEmptyPGresult(conn,
+ PGRES_BATCH_ABORTED);
+ if (!conn->result)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("out of memory"));
+ pqSaveErrorResult(conn);
+ return false;
+ }
+ conn->asyncStatus = PGASYNC_READY;
+ }
+ else
+ {
+ /* allow parsing to continue */
+ conn->asyncStatus = PGASYNC_BUSY;
+ }
+
+ return true;
+}
+
/*
* PQgetResult
@@ -1749,10 +2222,32 @@ PQgetResult(PGconn *conn)
switch (conn->asyncStatus)
{
case PGASYNC_IDLE:
+ case PGASYNC_QUEUED:
res = NULL; /* query is complete */
break;
case PGASYNC_READY:
res = pqPrepareAsyncResult(conn);
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ /*
+ * batched queries aren't followed by a Sync to put us back in
+ * PGASYNC_IDLE state, and when we do get a sync we could
+ * still have another batch coming after this one.
+ *
+ * The connection isn't idle since we can't submit new
+ * nonbatched commands. It isn't also busy since the current
+ * command is done and we need to process a new one.
+ */
+ conn->asyncStatus = PGASYNC_QUEUED;
+ }
+ else
+ {
+ /* Set the state back to BUSY, allowing parsing to proceed. */
+ conn->asyncStatus = PGASYNC_BUSY;
+ }
+ break;
+ case PGASYNC_READY_MORE:
+ res = pqPrepareAsyncResult(conn);
/* Set the state back to BUSY, allowing parsing to proceed. */
conn->asyncStatus = PGASYNC_BUSY;
break;
@@ -1932,6 +2427,13 @@ PQexecStart(PGconn *conn)
if (!conn)
return false;
+ if (conn->asyncStatus == PGASYNC_QUEUED || conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("Synchronous command execution functions are not allowed in batch mode\n"));
+ return false;
+ }
+
/*
* Silently discard any prior query result that application didn't eat.
* This is probably poor design, but it's here for backward compatibility.
@@ -2126,6 +2628,9 @@ PQsendDescribePortal(PGconn *conn, const char *portal)
static int
PQsendDescribe(PGconn *conn, char desc_type, const char *desc_target)
{
+ PGcommandQueueEntry *pipeCmd = NULL;
+ PGQueryClass *queryclass;
+
/* Treat null desc_target as empty string */
if (!desc_target)
desc_target = "";
@@ -2141,6 +2646,20 @@ PQsendDescribe(PGconn *conn, char desc_type, const char *desc_target)
return 0;
}
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ pipeCmd = PQmakePipelinedCommand(conn);
+
+ if (pipeCmd == NULL)
+ return 0; /* error msg already set */
+
+ queryclass = &pipeCmd->queryclass;
+ }
+ else
+ {
+ queryclass = &conn->queryclass;
+ }
+
/* construct the Describe message */
if (pqPutMsgStart('D', false, conn) < 0 ||
pqPutc(desc_type, conn) < 0 ||
@@ -2149,15 +2668,18 @@ PQsendDescribe(PGconn *conn, char desc_type, const char *desc_target)
goto sendFailed;
/* construct the Sync message */
- if (pqPutMsgStart('S', false, conn) < 0 ||
- pqPutMsgEnd(conn) < 0)
- goto sendFailed;
+ if (conn->batch_status == PQBATCH_MODE_OFF)
+ {
+ if (pqPutMsgStart('S', false, conn) < 0 ||
+ pqPutMsgEnd(conn) < 0)
+ goto sendFailed;
+ }
/* remember we are doing a Describe */
- conn->queryclass = PGQUERY_DESCRIBE;
+ *queryclass = PGQUERY_DESCRIBE;
/* reset last-query string (not relevant now) */
- if (conn->last_query)
+ if (conn->last_query && conn->batch_status != PQBATCH_MODE_OFF)
{
free(conn->last_query);
conn->last_query = NULL;
@@ -2171,10 +2693,14 @@ PQsendDescribe(PGconn *conn, char desc_type, const char *desc_target)
goto sendFailed;
/* OK, it's launched! */
- conn->asyncStatus = PGASYNC_BUSY;
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ PQappendPipelinedCommand(conn, pipeCmd);
+ else
+ conn->asyncStatus = PGASYNC_BUSY;
return 1;
sendFailed:
+ PQrecyclePipelinedCommand(conn, pipeCmd);
pqHandleSendFailure(conn);
return 0;
}
@@ -2569,6 +3095,13 @@ PQfn(PGconn *conn,
/* clear the error string */
resetPQExpBuffer(&conn->errorMessage);
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("Synchronous command execution functions are not allowed in batch mode\n"));
+ return NULL;
+ }
+
if (conn->sock == PGINVALID_SOCKET || conn->asyncStatus != PGASYNC_IDLE ||
conn->result != NULL)
{
diff --git a/src/interfaces/libpq/fe-protocol2.c b/src/interfaces/libpq/fe-protocol2.c
index 3b0500f..c01f1a2 100644
--- a/src/interfaces/libpq/fe-protocol2.c
+++ b/src/interfaces/libpq/fe-protocol2.c
@@ -412,6 +412,12 @@ pqParseInput2(PGconn *conn)
{
char id;
+ if (conn->asyncStatus == PGASYNC_QUEUED || conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ fprintf(stderr, "internal error, attempt to read v2 protocol in batch mode");
+ abort();
+ }
+
/*
* Loop to parse successive complete messages available in the buffer.
*/
diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 53776e2..e24d7ce 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -220,10 +220,18 @@ pqParseInput3(PGconn *conn)
return;
conn->asyncStatus = PGASYNC_READY;
break;
- case 'Z': /* backend is ready for new query */
+ case 'Z': /* sync response, backend is ready for new query */
if (getReadyForQuery(conn))
return;
- conn->asyncStatus = PGASYNC_IDLE;
+ if (conn->batch_status != PQBATCH_MODE_OFF)
+ {
+ conn->batch_status = PQBATCH_MODE_ON;
+ conn->result = PQmakeEmptyPGresult(conn,
+ PGRES_BATCH_END);
+ conn->asyncStatus = PGASYNC_READY;
+ }
+ else
+ conn->asyncStatus = PGASYNC_IDLE;
break;
case 'I': /* empty query */
if (conn->result == NULL)
@@ -880,6 +888,9 @@ pqGetErrorNotice3(PGconn *conn, bool isError)
PQExpBufferData workBuf;
char id;
+ if (isError && conn->batch_status != PQBATCH_MODE_OFF)
+ conn->batch_status = PQBATCH_MODE_ABORTED;
+
/*
* Since the fields might be pretty long, we create a temporary
* PQExpBuffer rather than using conn->workBuffer. workBuffer is intended
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index e7496c5..321fc60 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -95,7 +95,10 @@ typedef enum
PGRES_NONFATAL_ERROR, /* notice or warning message */
PGRES_FATAL_ERROR, /* query failed */
PGRES_COPY_BOTH, /* Copy In/Out data transfer in progress */
- PGRES_SINGLE_TUPLE /* single tuple from larger resultset */
+ PGRES_SINGLE_TUPLE, /* single tuple from larger resultset */
+ PGRES_BATCH_END, /* end of a batch of commands */
+ PGRES_BATCH_ABORTED, /* Command didn't run because of an abort
+ * earlier in a batch */
} ExecStatusType;
typedef enum
@@ -134,6 +137,17 @@ typedef enum
PQPING_NO_ATTEMPT /* connection not attempted (bad params) */
} PGPing;
+/*
+ * PQBatchStatus - Current status of batch mode
+ */
+
+typedef enum
+{
+ PQBATCH_MODE_OFF,
+ PQBATCH_MODE_ON,
+ PQBATCH_MODE_ABORTED
+} PQBatchStatus;
+
/* PGconn encapsulates a connection to the backend.
* The contents of this struct are not supposed to be known to applications.
*/
@@ -425,6 +439,14 @@ extern PGresult *PQgetResult(PGconn *conn);
extern int PQisBusy(PGconn *conn);
extern int PQconsumeInput(PGconn *conn);
+/* Routines for batch mode management */
+extern int PQbatchStatus(PGconn *conn);
+extern int PQbatchQueueCount(PGconn *conn);
+extern int PQenterBatchMode(PGconn *conn);
+extern int PQexitBatchMode(PGconn *conn);
+extern int PQbatchSyncQueue(PGconn *conn);
+extern int PQbatchProcessQueue(PGconn *conn);
+
/* LISTEN/NOTIFY support */
extern PGnotify *PQnotifies(PGconn *conn);
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 335568b..619f5c0 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -215,10 +215,15 @@ typedef enum
{
PGASYNC_IDLE, /* nothing's happening, dude */
PGASYNC_BUSY, /* query in progress */
- PGASYNC_READY, /* result ready for PQgetResult */
+ PGASYNC_READY, /* query done, waiting for client to fetch
+ * result */
+ PGASYNC_READY_MORE, /* query done, waiting for client to fetch
+ * result, More results expected from this
+ * query */
PGASYNC_COPY_IN, /* Copy In data transfer in progress */
PGASYNC_COPY_OUT, /* Copy Out data transfer in progress */
- PGASYNC_COPY_BOTH /* Copy In/Out data transfer in progress */
+ PGASYNC_COPY_BOTH, /* Copy In/Out data transfer in progress */
+ PGASYNC_QUEUED /* Current query done, more in queue */
} PGAsyncStatusType;
/* PGQueryClass tracks which query protocol we are now executing */
@@ -227,7 +232,8 @@ typedef enum
PGQUERY_SIMPLE, /* simple Query protocol (PQexec) */
PGQUERY_EXTENDED, /* full Extended protocol (PQexecParams) */
PGQUERY_PREPARE, /* Parse only (PQprepare) */
- PGQUERY_DESCRIBE /* Describe Statement or Portal */
+ PGQUERY_DESCRIBE, /* Describe Statement or Portal */
+ PGQUERY_SYNC /* A protocol sync to end a batch */
} PGQueryClass;
/* PGSetenvStatusType defines the state of the PQSetenv state machine */
@@ -297,6 +303,22 @@ typedef enum pg_conn_host_type
CHT_UNIX_SOCKET
} pg_conn_host_type;
+/* An entry in the pending command queue. Used by batch mode to keep track
+ * of the expected results of future commands we've dispatched.
+ *
+ * Note that entries in this list are reused by being zeroed and appended to
+ * the tail when popped off the head. The entry with null next pointer is not
+ * the end of the list of expected commands, that's the tail pointer in
+ * pg_conn.
+ */
+typedef struct pgCommandQueueEntry
+{
+ PGQueryClass queryclass; /* Query type; PGQUERY_SYNC for sync msg */
+ char *query; /* SQL command, or NULL if unknown */
+ struct pgCommandQueueEntry *next;
+} PGcommandQueueEntry;
+
+
/*
* pg_conn_host stores all information about one of possibly several hosts
* mentioned in the connection string. Derived by splitting the pghost
@@ -384,6 +406,7 @@ struct pg_conn
bool options_valid; /* true if OK to attempt connection */
bool nonblocking; /* whether this connection is using nonblock
* sending semantics */
+ PQBatchStatus batch_status; /* Batch(pipelining) mode status of connection */
bool singleRowMode; /* return current query result row-by-row? */
char copy_is_binary; /* 1 = copy binary, 0 = copy text */
int copy_already_done; /* # bytes already returned in COPY
@@ -396,6 +419,16 @@ struct pg_conn
int whichhost; /* host we're currently considering */
pg_conn_host *connhost; /* details about each possible host */
+ /*
+ * The command queue
+ *
+ * head is the next pending cmd, tail is where we append new commands.
+ * Freed entries for recycling go on the recycle linked list.
+ */
+ PGcommandQueueEntry *cmd_queue_head;
+ PGcommandQueueEntry *cmd_queue_tail;
+ PGcommandQueueEntry *cmd_queue_recycle;
+
/* Connection data */
pgsocket sock; /* FD for socket, PGINVALID_SOCKET if
* unconnected */
@@ -684,6 +717,8 @@ extern char *libpq_ngettext(const char *msgid, const char *msgid_plural, unsigne
#define libpq_ngettext(s, p, n) ((n) == 1 ? (s) : (p))
#endif
+#define libpq_gettext_noop(x) (x)
+
/*
* These macros are needed to let error-handling code be portable between
* Unix and Windows. (ugh)