mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-21 08:29:39 +08:00
530 lines
14 KiB
C
530 lines
14 KiB
C
/****************************************************************************
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* pending.c
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* $PostgreSQL: pgsql/contrib/dbmirror/pending.c,v 1.15 2003/11/29 22:39:19 pgsql Exp $
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*
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* This file contains a trigger for Postgresql-7.x to record changes to tables
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* to a pending table for mirroring.
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* All tables that should be mirrored should have this trigger hooked up to it.
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*
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* Written by Steven Singer (ssinger@navtechinc.com)
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* (c) 2001-2002 Navtech Systems Support Inc.
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* ALL RIGHTS RESERVED
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*
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* Permission to use, copy, modify, and distribute this software and its
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* documentation for any purpose, without fee, and without a written agreement
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* is hereby granted, provided that the above copyright notice and this
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* paragraph and the following two paragraphs appear in all copies.
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*
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* IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
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* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
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* DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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*
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***************************************************************************/
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#include <postgres.h>
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#include <executor/spi.h>
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#include <commands/trigger.h>
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#include <utils/lsyscache.h>
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enum FieldUsage
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{
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PRIMARY = 0, NONPRIMARY, ALL, NUM_FIELDUSAGE
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};
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int storePending(char *cpTableName, HeapTuple tBeforeTuple,
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HeapTuple tAfterTuple,
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TupleDesc tTupdesc,
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TriggerData *tpTrigdata, char cOp);
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int storeKeyInfo(char *cpTableName, HeapTuple tTupleData, TupleDesc tTuplDesc,
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TriggerData *tpTrigdata);
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int storeData(char *cpTableName, HeapTuple tTupleData, TupleDesc tTupleDesc,
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TriggerData *tpTrigData, int iIncludeKeyData);
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int2vector *getPrimaryKey(Oid tblOid);
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char *packageData(HeapTuple tTupleData, TupleDesc tTupleDecs,
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TriggerData *tTrigData,
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enum FieldUsage eKeyUsage);
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#define BUFFER_SIZE 256
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#define MAX_OID_LEN 10
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/*#define DEBUG_OUTPUT 1 */
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extern Datum recordchange(PG_FUNCTION_ARGS);
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PG_FUNCTION_INFO_V1(recordchange);
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/*****************************************************************************
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* The entry point for the trigger function.
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* The Trigger takes a single SQL 'text' argument indicating the name of the
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* table the trigger was applied to. If this name is incorrect so will the
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* mirroring.
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****************************************************************************/
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Datum
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recordchange(PG_FUNCTION_ARGS)
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{
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TriggerData *trigdata;
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TupleDesc tupdesc;
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HeapTuple beforeTuple = NULL;
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HeapTuple afterTuple = NULL;
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HeapTuple retTuple = NULL;
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char *tblname;
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char op = 0;
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char *schemaname;
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char *fullyqualtblname;
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if (fcinfo->context != NULL)
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{
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if (SPI_connect() < 0)
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{
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elog(NOTICE, "storePending could not connect to SPI");
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return -1;
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}
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trigdata = (TriggerData *) fcinfo->context;
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/* Extract the table name */
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tblname = SPI_getrelname(trigdata->tg_relation);
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#ifndef NOSCHEMAS
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schemaname = get_namespace_name(RelationGetNamespace(trigdata->tg_relation));
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fullyqualtblname = SPI_palloc(strlen(tblname) +
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strlen(schemaname) + 6);
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sprintf(fullyqualtblname, "\"%s\".\"%s\"",
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schemaname, tblname);
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#else
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fullyqualtblname = SPI_palloc(strlen(tblname) + 3);
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sprintf(fullyqualtblname, "\"%s\"", tblname);
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#endif
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tupdesc = trigdata->tg_relation->rd_att;
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if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
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{
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retTuple = trigdata->tg_newtuple;
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beforeTuple = trigdata->tg_trigtuple;
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afterTuple = trigdata->tg_newtuple;
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op = 'u';
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}
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else if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
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{
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retTuple = trigdata->tg_trigtuple;
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afterTuple = trigdata->tg_trigtuple;
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op = 'i';
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}
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else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
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{
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retTuple = trigdata->tg_trigtuple;
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beforeTuple = trigdata->tg_trigtuple;
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op = 'd';
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}
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if (storePending(fullyqualtblname, beforeTuple, afterTuple, tupdesc, trigdata, op))
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{
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/* An error occoured. Skip the operation. */
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ereport(ERROR,
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(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
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errmsg("operation could not be mirrored")));
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return PointerGetDatum(NULL);
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}
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "returning on success");
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#endif
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SPI_pfree(fullyqualtblname);
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SPI_finish();
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return PointerGetDatum(retTuple);
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}
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else
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{
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/*
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* Not being called as a trigger.
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*/
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return PointerGetDatum(NULL);
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}
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}
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/*****************************************************************************
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* Constructs and executes an SQL query to write a record of this tuple change
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* to the pending table.
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*****************************************************************************/
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int
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storePending(char *cpTableName, HeapTuple tBeforeTuple,
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HeapTuple tAfterTuple,
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TupleDesc tTupDesc,
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TriggerData *tpTrigData, char cOp)
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{
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char *cpQueryBase = "INSERT INTO \"Pending\" (\"TableName\",\"Op\",\"XID\") VALUES ($1,$2,$3)";
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int iResult = 0;
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HeapTuple tCurTuple;
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/* Points the current tuple(before or after) */
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Datum saPlanData[4];
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Oid taPlanArgTypes[3] = {NAMEOID, CHAROID, INT4OID};
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void *vpPlan;
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tCurTuple = tBeforeTuple ? tBeforeTuple : tAfterTuple;
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vpPlan = SPI_prepare(cpQueryBase, 3, taPlanArgTypes);
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if (vpPlan == NULL)
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elog(NOTICE, "error creating plan");
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/* SPI_saveplan(vpPlan); */
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saPlanData[0] = PointerGetDatum(cpTableName);
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saPlanData[1] = CharGetDatum(cOp);
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saPlanData[2] = Int32GetDatum(GetCurrentTransactionId());
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iResult = SPI_execp(vpPlan, saPlanData, NULL, 1);
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if (iResult < 0)
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elog(NOTICE, "storedPending fired (%s) returned %d", cpQueryBase, iResult);
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "row successfully stored in pending table");
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#endif
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if (cOp == 'd')
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{
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/**
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* This is a record of a delete operation.
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* Just store the key data.
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*/
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iResult = storeKeyInfo(cpTableName, tBeforeTuple, tTupDesc, tpTrigData);
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}
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else if (cOp == 'i')
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{
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/**
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* An Insert operation.
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* Store all data
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*/
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iResult = storeData(cpTableName, tAfterTuple, tTupDesc, tpTrigData, TRUE);
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}
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else
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{
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/* op must be an update. */
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iResult = storeKeyInfo(cpTableName, tBeforeTuple, tTupDesc, tpTrigData);
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iResult = iResult ? iResult : storeData(cpTableName, tAfterTuple, tTupDesc,
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tpTrigData, TRUE);
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}
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "done storing keyinfo");
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#endif
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return iResult;
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}
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int
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storeKeyInfo(char *cpTableName, HeapTuple tTupleData,
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TupleDesc tTupleDesc,
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TriggerData *tpTrigData)
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{
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Oid saPlanArgTypes[1] = {NAMEOID};
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char *insQuery = "INSERT INTO \"PendingData\" (\"SeqId\",\"IsKey\",\"Data\") VALUES(currval('\"Pending_SeqId_seq\"'),'t',$1)";
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void *pplan;
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Datum saPlanData[1];
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char *cpKeyData;
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int iRetCode;
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pplan = SPI_prepare(insQuery, 1, saPlanArgTypes);
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if (pplan == NULL)
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{
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elog(NOTICE, "could not prepare INSERT plan");
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return -1;
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}
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/* pplan = SPI_saveplan(pplan); */
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cpKeyData = packageData(tTupleData, tTupleDesc, tpTrigData, PRIMARY);
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if (cpKeyData == NULL)
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ereport(ERROR,
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(errcode(ERRCODE_UNDEFINED_OBJECT),
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/* cpTableName already contains quotes... */
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errmsg("there is no PRIMARY KEY for table %s",
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cpTableName)));
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "key data: %s", cpKeyData);
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#endif
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saPlanData[0] = PointerGetDatum(cpKeyData);
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iRetCode = SPI_execp(pplan, saPlanData, NULL, 1);
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if (cpKeyData != NULL)
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SPI_pfree(cpKeyData);
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if (iRetCode != SPI_OK_INSERT)
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{
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elog(NOTICE, "error inserting row in pendingDelete");
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return -1;
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}
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "insert successful");
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#endif
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return 0;
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}
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int2vector *
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getPrimaryKey(Oid tblOid)
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{
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char *queryBase;
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char *query;
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bool isNull;
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int2vector *resultKey;
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int2vector *tpResultKey;
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HeapTuple resTuple;
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Datum resDatum;
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int ret;
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queryBase = "SELECT indkey FROM pg_index WHERE indisprimary='t' AND indrelid=";
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query = SPI_palloc(strlen(queryBase) + MAX_OID_LEN + 1);
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sprintf(query, "%s%d", queryBase, tblOid);
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ret = SPI_exec(query, 1);
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SPI_pfree(query);
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if (ret != SPI_OK_SELECT || SPI_processed != 1)
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return NULL;
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resTuple = SPI_tuptable->vals[0];
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resDatum = SPI_getbinval(resTuple, SPI_tuptable->tupdesc, 1, &isNull);
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tpResultKey = (int2vector *) DatumGetPointer(resDatum);
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resultKey = SPI_palloc(sizeof(int2vector));
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memcpy(resultKey, tpResultKey, sizeof(int2vector));
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return resultKey;
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}
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/******************************************************************************
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* Stores a copy of the non-key data for the row.
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*****************************************************************************/
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int
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storeData(char *cpTableName, HeapTuple tTupleData, TupleDesc tTupleDesc,
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TriggerData *tpTrigData, int iIncludeKeyData)
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{
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Oid planArgTypes[1] = {NAMEOID};
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char *insQuery = "INSERT INTO \"PendingData\" (\"SeqId\",\"IsKey\",\"Data\") VALUES(currval('\"Pending_SeqId_seq\"'),'f',$1)";
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void *pplan;
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Datum planData[1];
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char *cpKeyData;
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int iRetValue;
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pplan = SPI_prepare(insQuery, 1, planArgTypes);
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if (pplan == NULL)
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{
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elog(NOTICE, "could not prepare INSERT plan");
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return -1;
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}
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/* pplan = SPI_saveplan(pplan); */
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if (iIncludeKeyData == 0)
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cpKeyData = packageData(tTupleData, tTupleDesc, tpTrigData, NONPRIMARY);
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else
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cpKeyData = packageData(tTupleData, tTupleDesc, tpTrigData, ALL);
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planData[0] = PointerGetDatum(cpKeyData);
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iRetValue = SPI_execp(pplan, planData, NULL, 1);
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if (cpKeyData != 0)
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SPI_pfree(cpKeyData);
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if (iRetValue != SPI_OK_INSERT)
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{
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elog(NOTICE, "error inserting row in pendingDelete");
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return -1;
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}
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "insert successful");
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#endif
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return 0;
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}
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/**
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* Packages the data in tTupleData into a string of the format
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* FieldName='value text' where any quotes inside of value text
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* are escaped with a backslash and any backslashes in value text
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* are esacped by a second back slash.
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*
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* tTupleDesc should be a description of the tuple stored in
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* tTupleData.
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*
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* eFieldUsage specifies which fields to use.
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* PRIMARY implies include only primary key fields.
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* NONPRIMARY implies include only non-primary key fields.
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* ALL implies include all fields.
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*/
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char *
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packageData(HeapTuple tTupleData, TupleDesc tTupleDesc,
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TriggerData *tpTrigData,
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enum FieldUsage eKeyUsage)
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{
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int iNumCols;
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int2vector *tpPKeys = NULL;
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int iColumnCounter;
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char *cpDataBlock;
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int iDataBlockSize;
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int iUsedDataBlock;
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iNumCols = tTupleDesc->natts;
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if (eKeyUsage != ALL)
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{
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tpPKeys = getPrimaryKey(tpTrigData->tg_relation->rd_id);
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if (tpPKeys == NULL)
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return NULL;
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}
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#if defined DEBUG_OUTPUT
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if (tpPKeys != NULL)
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elog(NOTICE, "have primary keys");
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#endif
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cpDataBlock = SPI_palloc(BUFFER_SIZE);
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iDataBlockSize = BUFFER_SIZE;
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iUsedDataBlock = 0; /* To account for the null */
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for (iColumnCounter = 1; iColumnCounter <= iNumCols; iColumnCounter++)
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{
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int iIsPrimaryKey;
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int iPrimaryKeyIndex;
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char *cpUnFormatedPtr;
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char *cpFormatedPtr;
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char *cpFieldName;
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char *cpFieldData;
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if (eKeyUsage != ALL)
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{
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/* Determine if this is a primary key or not. */
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iIsPrimaryKey = 0;
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for (iPrimaryKeyIndex = 0; (*tpPKeys)[iPrimaryKeyIndex] != 0;
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iPrimaryKeyIndex++)
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{
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if ((*tpPKeys)[iPrimaryKeyIndex] == iColumnCounter)
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{
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iIsPrimaryKey = 1;
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break;
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}
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}
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if (iIsPrimaryKey ? (eKeyUsage != PRIMARY) : (eKeyUsage != NONPRIMARY))
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{
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/**
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* Don't use.
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*/
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "skipping column");
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#endif
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continue;
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}
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} /* KeyUsage!=ALL */
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#ifndef NODROPCOLUMN
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if(tTupleDesc->attrs[iColumnCounter-1]->attisdropped)
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{
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/**
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* This column has been dropped.
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* Do not mirror it.
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*/
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continue;
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}
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#endif
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cpFieldName = DatumGetPointer(NameGetDatum(&tTupleDesc->attrs
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[iColumnCounter - 1]->attname));
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "field name: %s", cpFieldName);
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#endif
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while (iDataBlockSize - iUsedDataBlock < strlen(cpFieldName) + 6)
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{
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cpDataBlock = SPI_repalloc(cpDataBlock, iDataBlockSize + BUFFER_SIZE);
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iDataBlockSize = iDataBlockSize + BUFFER_SIZE;
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}
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sprintf(cpDataBlock + iUsedDataBlock, "\"%s\"=", cpFieldName);
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iUsedDataBlock = iUsedDataBlock + strlen(cpFieldName) + 3;
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cpFieldData = SPI_getvalue(tTupleData, tTupleDesc, iColumnCounter);
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cpUnFormatedPtr = cpFieldData;
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cpFormatedPtr = cpDataBlock + iUsedDataBlock;
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if (cpFieldData != NULL)
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{
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*cpFormatedPtr = '\'';
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iUsedDataBlock++;
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cpFormatedPtr++;
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}
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else
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{
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sprintf(cpFormatedPtr, " ");
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iUsedDataBlock++;
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cpFormatedPtr++;
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continue;
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}
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "field data: \"%s\"", cpFieldData);
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elog(NOTICE, "starting format loop");
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#endif
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while (*cpUnFormatedPtr != 0)
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{
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while (iDataBlockSize - iUsedDataBlock < 2)
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{
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cpDataBlock = SPI_repalloc(cpDataBlock, iDataBlockSize + BUFFER_SIZE);
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iDataBlockSize = iDataBlockSize + BUFFER_SIZE;
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cpFormatedPtr = cpDataBlock + iUsedDataBlock;
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}
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if (*cpUnFormatedPtr == '\\' || *cpUnFormatedPtr == '\'')
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{
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*cpFormatedPtr = '\\';
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cpFormatedPtr++;
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iUsedDataBlock++;
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}
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*cpFormatedPtr = *cpUnFormatedPtr;
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cpFormatedPtr++;
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cpUnFormatedPtr++;
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iUsedDataBlock++;
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}
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SPI_pfree(cpFieldData);
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while (iDataBlockSize - iUsedDataBlock < 3)
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{
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cpDataBlock = SPI_repalloc(cpDataBlock, iDataBlockSize + BUFFER_SIZE);
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iDataBlockSize = iDataBlockSize + BUFFER_SIZE;
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cpFormatedPtr = cpDataBlock + iUsedDataBlock;
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}
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sprintf(cpFormatedPtr, "' ");
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iUsedDataBlock = iUsedDataBlock + 2;
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "data block: \"%s\"", cpDataBlock);
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#endif
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} /* for iColumnCounter */
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if (tpPKeys != NULL)
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SPI_pfree(tpPKeys);
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#if defined DEBUG_OUTPUT
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elog(NOTICE, "returning DataBlockSize:%d iUsedDataBlock:%d", iDataBlockSize,
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iUsedDataBlock);
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#endif
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memset(cpDataBlock + iUsedDataBlock, 0, iDataBlockSize - iUsedDataBlock);
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return cpDataBlock;
|
|
|
|
}
|