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Remove IndexIsValid(), IndexIsReady(), IndexIsLive() in favor of accessing the index structure directly. These macros haven't been used consistently, and the original reason of maintaining source compatibility with PostgreSQL 9.2 is gone. Discussion: https://www.postgresql.org/message-id/flat/d419147c-09d4-6196-5d9d-0234b230880a%402ndquadrant.com
181 lines
5.0 KiB
C
181 lines
5.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* tcn.c
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* triggered change notification support for PostgreSQL
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*
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* Portions Copyright (c) 2011-2018, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* contrib/tcn/tcn.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/htup_details.h"
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#include "executor/spi.h"
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#include "commands/async.h"
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#include "commands/trigger.h"
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#include "lib/stringinfo.h"
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#include "utils/rel.h"
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#include "utils/syscache.h"
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PG_MODULE_MAGIC;
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/*
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* Copy from s (for source) to r (for result), wrapping with q (quote)
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* characters and doubling any quote characters found.
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*/
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static void
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strcpy_quoted(StringInfo r, const char *s, const char q)
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{
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appendStringInfoCharMacro(r, q);
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while (*s)
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{
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if (*s == q)
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appendStringInfoCharMacro(r, q);
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appendStringInfoCharMacro(r, *s);
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s++;
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}
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appendStringInfoCharMacro(r, q);
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}
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/*
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* triggered_change_notification
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*
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* This trigger function will send a notification of data modification with
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* primary key values. The channel will be "tcn" unless the trigger is
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* created with a parameter, in which case that parameter will be used.
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*/
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PG_FUNCTION_INFO_V1(triggered_change_notification);
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Datum
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triggered_change_notification(PG_FUNCTION_ARGS)
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{
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TriggerData *trigdata = (TriggerData *) fcinfo->context;
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Trigger *trigger;
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int nargs;
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HeapTuple trigtuple;
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Relation rel;
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TupleDesc tupdesc;
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char *channel;
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char operation;
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StringInfo payload = makeStringInfo();
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bool foundPK;
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List *indexoidlist;
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ListCell *indexoidscan;
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/* make sure it's called as a trigger */
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if (!CALLED_AS_TRIGGER(fcinfo))
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ereport(ERROR,
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(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
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errmsg("triggered_change_notification: must be called as trigger")));
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/* and that it's called after the change */
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if (!TRIGGER_FIRED_AFTER(trigdata->tg_event))
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ereport(ERROR,
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(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
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errmsg("triggered_change_notification: must be called after the change")));
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/* and that it's called for each row */
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if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
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ereport(ERROR,
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(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
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errmsg("triggered_change_notification: must be called for each row")));
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if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
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operation = 'I';
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else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
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operation = 'U';
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else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
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operation = 'D';
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else
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{
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elog(ERROR, "triggered_change_notification: trigger fired by unrecognized operation");
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operation = 'X'; /* silence compiler warning */
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}
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trigger = trigdata->tg_trigger;
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nargs = trigger->tgnargs;
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if (nargs > 1)
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ereport(ERROR,
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(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
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errmsg("triggered_change_notification: must not be called with more than one parameter")));
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if (nargs == 0)
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channel = "tcn";
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else
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channel = trigger->tgargs[0];
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/* get tuple data */
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trigtuple = trigdata->tg_trigtuple;
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rel = trigdata->tg_relation;
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tupdesc = rel->rd_att;
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foundPK = false;
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/*
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* Get the list of index OIDs for the table from the relcache, and look up
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* each one in the pg_index syscache until we find one marked primary key
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* (hopefully there isn't more than one such).
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*/
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indexoidlist = RelationGetIndexList(rel);
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foreach(indexoidscan, indexoidlist)
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{
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Oid indexoid = lfirst_oid(indexoidscan);
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HeapTuple indexTuple;
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Form_pg_index index;
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indexTuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexoid));
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if (!HeapTupleIsValid(indexTuple)) /* should not happen */
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elog(ERROR, "cache lookup failed for index %u", indexoid);
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index = (Form_pg_index) GETSTRUCT(indexTuple);
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/* we're only interested if it is the primary key and valid */
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if (index->indisprimary && index->indisvalid)
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{
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int indnkeyatts = index->indnkeyatts;
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if (indnkeyatts > 0)
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{
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int i;
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foundPK = true;
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strcpy_quoted(payload, RelationGetRelationName(rel), '"');
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appendStringInfoCharMacro(payload, ',');
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appendStringInfoCharMacro(payload, operation);
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for (i = 0; i < indnkeyatts; i++)
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{
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int colno = index->indkey.values[i];
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Form_pg_attribute attr = TupleDescAttr(tupdesc, colno - 1);
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appendStringInfoCharMacro(payload, ',');
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strcpy_quoted(payload, NameStr(attr->attname), '"');
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appendStringInfoCharMacro(payload, '=');
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strcpy_quoted(payload, SPI_getvalue(trigtuple, tupdesc, colno), '\'');
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}
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Async_Notify(channel, payload->data);
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}
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ReleaseSysCache(indexTuple);
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break;
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}
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ReleaseSysCache(indexTuple);
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}
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list_free(indexoidlist);
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if (!foundPK)
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ereport(ERROR,
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(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
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errmsg("triggered_change_notification: must be called on a table with a primary key")));
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return PointerGetDatum(NULL); /* after trigger; value doesn't matter */
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}
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