diff options
Diffstat (limited to 'src/backend/tcop/dest.c')
| -rw-r--r-- | src/backend/tcop/dest.c | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/src/backend/tcop/dest.c b/src/backend/tcop/dest.c new file mode 100644 index 0000000..c952cbe --- /dev/null +++ b/src/backend/tcop/dest.c @@ -0,0 +1,300 @@ +/*------------------------------------------------------------------------- + * + * dest.c + * support for communication destinations + * + * + * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/backend/tcop/dest.c + * + *------------------------------------------------------------------------- + */ +/* + * INTERFACE ROUTINES + * BeginCommand - initialize the destination at start of command + * CreateDestReceiver - create tuple receiver object for destination + * EndCommand - clean up the destination at end of command + * NullCommand - tell dest that an empty query string was recognized + * ReadyForQuery - tell dest that we are ready for a new query + * + * NOTES + * These routines do the appropriate work before and after + * tuples are returned by a query to keep the backend and the + * "destination" portals synchronized. + */ + +#include "postgres.h" + +#include "access/printsimple.h" +#include "access/printtup.h" +#include "access/xact.h" +#include "commands/copy.h" +#include "commands/createas.h" +#include "commands/matview.h" +#include "executor/functions.h" +#include "executor/tqueue.h" +#include "executor/tstoreReceiver.h" +#include "libpq/libpq.h" +#include "libpq/pqformat.h" +#include "utils/portal.h" + + +/* ---------------- + * dummy DestReceiver functions + * ---------------- + */ +static bool +donothingReceive(TupleTableSlot *slot, DestReceiver *self) +{ + return true; +} + +static void +donothingStartup(DestReceiver *self, int operation, TupleDesc typeinfo) +{ +} + +static void +donothingCleanup(DestReceiver *self) +{ + /* this is used for both shutdown and destroy methods */ +} + +/* ---------------- + * static DestReceiver structs for dest types needing no local state + * ---------------- + */ +static const DestReceiver donothingDR = { + donothingReceive, donothingStartup, donothingCleanup, donothingCleanup, + DestNone +}; + +static const DestReceiver debugtupDR = { + debugtup, debugStartup, donothingCleanup, donothingCleanup, + DestDebug +}; + +static const DestReceiver printsimpleDR = { + printsimple, printsimple_startup, donothingCleanup, donothingCleanup, + DestRemoteSimple +}; + +static const DestReceiver spi_printtupDR = { + spi_printtup, spi_dest_startup, donothingCleanup, donothingCleanup, + DestSPI +}; + +/* + * Globally available receiver for DestNone. + * + * It's ok to cast the constness away as any modification of the none receiver + * would be a bug (which gets easier to catch this way). + */ +DestReceiver *None_Receiver = (DestReceiver *) &donothingDR; + +/* ---------------- + * BeginCommand - initialize the destination at start of command + * ---------------- + */ +void +BeginCommand(CommandTag commandTag, CommandDest dest) +{ + /* Nothing to do at present */ +} + +/* ---------------- + * CreateDestReceiver - return appropriate receiver function set for dest + * ---------------- + */ +DestReceiver * +CreateDestReceiver(CommandDest dest) +{ + /* + * It's ok to cast the constness away as any modification of the none + * receiver would be a bug (which gets easier to catch this way). + */ + + switch (dest) + { + case DestRemote: + case DestRemoteExecute: + return printtup_create_DR(dest); + + case DestRemoteSimple: + return unconstify(DestReceiver *, &printsimpleDR); + + case DestNone: + return unconstify(DestReceiver *, &donothingDR); + + case DestDebug: + return unconstify(DestReceiver *, &debugtupDR); + + case DestSPI: + return unconstify(DestReceiver *, &spi_printtupDR); + + case DestTuplestore: + return CreateTuplestoreDestReceiver(); + + case DestIntoRel: + return CreateIntoRelDestReceiver(NULL); + + case DestCopyOut: + return CreateCopyDestReceiver(); + + case DestSQLFunction: + return CreateSQLFunctionDestReceiver(); + + case DestTransientRel: + return CreateTransientRelDestReceiver(InvalidOid); + + case DestTupleQueue: + return CreateTupleQueueDestReceiver(NULL); + } + + /* should never get here */ + pg_unreachable(); +} + +/* ---------------- + * EndCommand - clean up the destination at end of command + * ---------------- + */ +void +EndCommand(const QueryCompletion *qc, CommandDest dest, bool force_undecorated_output) +{ + char completionTag[COMPLETION_TAG_BUFSIZE]; + CommandTag tag; + const char *tagname; + + switch (dest) + { + case DestRemote: + case DestRemoteExecute: + case DestRemoteSimple: + + /* + * We assume the tagname is plain ASCII and therefore requires no + * encoding conversion. + * + * We no longer display LastOid, but to preserve the wire + * protocol, we write InvalidOid where the LastOid used to be + * written. + * + * All cases where LastOid was written also write nprocessed + * count, so just Assert that rather than having an extra test. + */ + tag = qc->commandTag; + tagname = GetCommandTagName(tag); + + if (command_tag_display_rowcount(tag) && !force_undecorated_output) + snprintf(completionTag, COMPLETION_TAG_BUFSIZE, + tag == CMDTAG_INSERT ? + "%s 0 " UINT64_FORMAT : "%s " UINT64_FORMAT, + tagname, qc->nprocessed); + else + snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s", tagname); + pq_putmessage('C', completionTag, strlen(completionTag) + 1); + + case DestNone: + case DestDebug: + case DestSPI: + case DestTuplestore: + case DestIntoRel: + case DestCopyOut: + case DestSQLFunction: + case DestTransientRel: + case DestTupleQueue: + break; + } +} + +/* ---------------- + * EndReplicationCommand - stripped down version of EndCommand + * + * For use by replication commands. + * ---------------- + */ +void +EndReplicationCommand(const char *commandTag) +{ + pq_putmessage('C', commandTag, strlen(commandTag) + 1); +} + +/* ---------------- + * NullCommand - tell dest that an empty query string was recognized + * + * This ensures that there will be a recognizable end to the response + * to an Execute message in the extended query protocol. + * ---------------- + */ +void +NullCommand(CommandDest dest) +{ + switch (dest) + { + case DestRemote: + case DestRemoteExecute: + case DestRemoteSimple: + + /* Tell the FE that we saw an empty query string */ + pq_putemptymessage('I'); + break; + + case DestNone: + case DestDebug: + case DestSPI: + case DestTuplestore: + case DestIntoRel: + case DestCopyOut: + case DestSQLFunction: + case DestTransientRel: + case DestTupleQueue: + break; + } +} + +/* ---------------- + * ReadyForQuery - tell dest that we are ready for a new query + * + * The ReadyForQuery message is sent so that the FE can tell when + * we are done processing a query string. + * In versions 3.0 and up, it also carries a transaction state indicator. + * + * Note that by flushing the stdio buffer here, we can avoid doing it + * most other places and thus reduce the number of separate packets sent. + * ---------------- + */ +void +ReadyForQuery(CommandDest dest) +{ + switch (dest) + { + case DestRemote: + case DestRemoteExecute: + case DestRemoteSimple: + { + StringInfoData buf; + + pq_beginmessage(&buf, 'Z'); + pq_sendbyte(&buf, TransactionBlockStatusCode()); + pq_endmessage(&buf); + } + /* Flush output at end of cycle in any case. */ + pq_flush(); + break; + + case DestNone: + case DestDebug: + case DestSPI: + case DestTuplestore: + case DestIntoRel: + case DestCopyOut: + case DestSQLFunction: + case DestTransientRel: + case DestTupleQueue: + break; + } +} |