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postgresql/contrib/dbmirror/pending.c

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/****************************************************************************
* pending.c
* $Id: pending.c,v 1.10 2002/11/26 03:08:00 momjian Exp $
*
* This file contains a trigger for Postgresql-7.x to record changes to tables
* to a pending table for mirroring.
* All tables that should be mirrored should have this trigger hooked up to it.
*
* Written by Steven Singer (ssinger@navtechinc.com)
* (c) 2001-2002 Navtech Systems Support Inc.
* ALL RIGHTS RESERVED
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without a written agreement
* is hereby granted, provided that the above copyright notice and this
* paragraph and the following two paragraphs appear in all copies.
*
* IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
* DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
*
***************************************************************************/
#include <postgres.h>
#include <executor/spi.h>
#include <commands/trigger.h>
#include <utils/lsyscache.h>
enum FieldUsage
{
PRIMARY = 0, NONPRIMARY, ALL, NUM_FIELDUSAGE
};
int storePending(char *cpTableName, HeapTuple tBeforeTuple,
HeapTuple tAfterTuple,
TupleDesc tTupdesc,
TriggerData *tpTrigdata, char cOp);
int storeKeyInfo(char *cpTableName, HeapTuple tTupleData, TupleDesc tTuplDesc,
TriggerData *tpTrigdata);
int storeData(char *cpTableName, HeapTuple tTupleData, TupleDesc tTupleDesc,
TriggerData *tpTrigData, int iIncludeKeyData);
int2vector *getPrimaryKey(Oid tblOid);
char *packageData(HeapTuple tTupleData, TupleDesc tTupleDecs,
TriggerData *tTrigData,
enum FieldUsage eKeyUsage);
#define BUFFER_SIZE 256
#define MAX_OID_LEN 10
/*#define DEBUG_OUTPUT 1 */
extern Datum recordchange(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(recordchange);
/*****************************************************************************
* The entry point for the trigger function.
* The Trigger takes a single SQL 'text' argument indicating the name of the
* table the trigger was applied to. If this name is incorrect so will the
* mirroring.
****************************************************************************/
Datum
recordchange(PG_FUNCTION_ARGS)
{
TriggerData *trigdata;
TupleDesc tupdesc;
HeapTuple beforeTuple = NULL;
HeapTuple afterTuple = NULL;
HeapTuple retTuple = NULL;
char *tblname;
char op = 0;
char *schemaname;
char *fullyqualtblname;
if (fcinfo->context != NULL)
{
if (SPI_connect() < 0)
{
elog(NOTICE, "storePending could not connect to SPI");
return -1;
}
trigdata = (TriggerData *) fcinfo->context;
/* Extract the table name */
tblname = SPI_getrelname(trigdata->tg_relation);
#ifndef NOSCHEMAS
schemaname = get_namespace_name(RelationGetNamespace(trigdata->tg_relation));
fullyqualtblname = SPI_palloc(strlen(tblname) +
strlen(schemaname) + 6);
sprintf(fullyqualtblname,"\"%s\".\"%s\"",
schemaname,tblname);
#else
fullyqualtblname = SPI_palloc(strlen(tblname + 3));
sprintf(fullyqualtblname,"\"%s\"",tblname);
#endif
tupdesc = trigdata->tg_relation->rd_att;
if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
{
retTuple = trigdata->tg_newtuple;
beforeTuple = trigdata->tg_trigtuple;
afterTuple = trigdata->tg_newtuple;
op = 'u';
}
else if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
{
retTuple = trigdata->tg_trigtuple;
afterTuple = trigdata->tg_trigtuple;
op = 'i';
}
else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
{
retTuple = trigdata->tg_trigtuple;
beforeTuple = trigdata->tg_trigtuple;
op = 'd';
}
if (storePending(fullyqualtblname, beforeTuple, afterTuple, tupdesc, trigdata, op))
{
/* An error occoured. Skip the operation. */
elog(ERROR, "Operation could not be mirrored");
return PointerGetDatum(NULL);
}
#if defined DEBUG_OUTPUT
elog(NOTICE, "Returning on success");
#endif
SPI_pfree(fullyqualtblname);
SPI_finish();
return PointerGetDatum(retTuple);
}
else
{
/*
* Not being called as a trigger.
*/
return PointerGetDatum(NULL);
}
}
/*****************************************************************************
* Constructs and executes an SQL query to write a record of this tuple change
* to the pending table.
*****************************************************************************/
int
storePending(char *cpTableName, HeapTuple tBeforeTuple,
HeapTuple tAfterTuple,
TupleDesc tTupDesc,
TriggerData *tpTrigData, char cOp)
{
char *cpQueryBase = "INSERT INTO \"Pending\" (\"TableName\",\"Op\",\"XID\") VALUES ($1,$2,$3)";
int iResult = 0;
HeapTuple tCurTuple;
//Points the current tuple(before or after)
Datum saPlanData[4];
Oid taPlanArgTypes[3] = {NAMEOID, CHAROID, INT4OID};
void *vpPlan;
tCurTuple = tBeforeTuple ? tBeforeTuple : tAfterTuple;
vpPlan = SPI_prepare(cpQueryBase, 3, taPlanArgTypes);
if (vpPlan == NULL)
elog(NOTICE, "Error creating plan");
/* SPI_saveplan(vpPlan); */
saPlanData[0] = PointerGetDatum(cpTableName);
saPlanData[1] = CharGetDatum(cOp);
saPlanData[2] = Int32GetDatum(GetCurrentTransactionId());
iResult = SPI_execp(vpPlan, saPlanData, NULL, 1);
if (iResult < 0)
elog(NOTICE, "storedPending fired (%s) returned %d", cpQueryBase, iResult);
#if defined DEBUG_OUTPUT
elog(NOTICE, "row successfully stored in pending table");
#endif
if (cOp == 'd')
{
/**
* This is a record of a delete operation.
* Just store the key data.
*/
iResult = storeKeyInfo(cpTableName, tBeforeTuple, tTupDesc, tpTrigData);
}
else if (cOp == 'i')
{
/**
* An Insert operation.
* Store all data
*/
iResult = storeData(cpTableName, tAfterTuple, tTupDesc, tpTrigData, TRUE);
}
else
{
/* op must be an update. */
iResult = storeKeyInfo(cpTableName, tBeforeTuple, tTupDesc, tpTrigData);
iResult = iResult ? iResult : storeData(cpTableName, tAfterTuple, tTupDesc,
tpTrigData, TRUE);
}
#if defined DEBUG_OUTPUT
elog(NOTICE, "Done storing keyinfo");
#endif
return iResult;
}
int
storeKeyInfo(char *cpTableName, HeapTuple tTupleData,
TupleDesc tTupleDesc,
TriggerData *tpTrigData)
{
Oid saPlanArgTypes[1] = {NAMEOID};
char *insQuery = "INSERT INTO \"PendingData\" (\"SeqId\",\"IsKey\",\"Data\") VALUES(currval('\"Pending_SeqId_seq\"'),'t',$1)";
void *pplan;
Datum saPlanData[1];
char *cpKeyData;
int iRetCode;
pplan = SPI_prepare(insQuery, 1, saPlanArgTypes);
if (pplan == NULL)
{
elog(NOTICE, "Could not prepare INSERT plan");
return -1;
}
/* pplan = SPI_saveplan(pplan); */
cpKeyData = packageData(tTupleData, tTupleDesc, tpTrigData, PRIMARY);
if (cpKeyData == NULL)
{
elog(ERROR,"Could not determine primary key data");
return -1;
}
#if defined DEBUG_OUTPUT
elog(NOTICE, "KeyData: %s", cpKeyData);
#endif
saPlanData[0] = PointerGetDatum(cpKeyData);
iRetCode = SPI_execp(pplan, saPlanData, NULL, 1);
if (cpKeyData != NULL)
SPI_pfree(cpKeyData);
if (iRetCode != SPI_OK_INSERT)
{
elog(NOTICE, "Error inserting row in pendingDelete");
return -1;
}
#if defined DEBUG_OUTPUT
elog(NOTICE, "Insert successful");
#endif
return 0;
}
int2vector *
getPrimaryKey(Oid tblOid)
{
char *queryBase;
char *query;
bool isNull;
int2vector *resultKey;
int2vector *tpResultKey;
HeapTuple resTuple;
Datum resDatum;
int ret;
queryBase = "SELECT indkey FROM pg_index WHERE indisprimary='t' AND indrelid=";
query = SPI_palloc(strlen(queryBase) + MAX_OID_LEN + 1);
sprintf(query, "%s%d", queryBase, tblOid);
ret = SPI_exec(query, 1);
if (ret != SPI_OK_SELECT || SPI_processed != 1)
{
elog(NOTICE, "Could not select primary index key");
return NULL;
}
resTuple = SPI_tuptable->vals[0];
resDatum = SPI_getbinval(resTuple, SPI_tuptable->tupdesc, 1, &isNull);
tpResultKey = (int2vector *) DatumGetPointer(resDatum);
resultKey = SPI_palloc(sizeof(int2vector));
memcpy(resultKey, tpResultKey, sizeof(int2vector));
SPI_pfree(query);
return resultKey;
}
/******************************************************************************
* Stores a copy of the non-key data for the row.
*****************************************************************************/
int
storeData(char *cpTableName, HeapTuple tTupleData, TupleDesc tTupleDesc,
TriggerData *tpTrigData, int iIncludeKeyData)
{
Oid planArgTypes[1] = {NAMEOID};
char *insQuery = "INSERT INTO \"PendingData\" (\"SeqId\",\"IsKey\",\"Data\") VALUES(currval('\"Pending_SeqId_seq\"'),'f',$1)";
void *pplan;
Datum planData[1];
char *cpKeyData;
int iRetValue;
pplan = SPI_prepare(insQuery, 1, planArgTypes);
if (pplan == NULL)
{
elog(NOTICE, "Could not prepare INSERT plan");
return -1;
}
/* pplan = SPI_saveplan(pplan); */
if (iIncludeKeyData == 0)
cpKeyData = packageData(tTupleData, tTupleDesc, tpTrigData, NONPRIMARY);
else
cpKeyData = packageData(tTupleData, tTupleDesc, tpTrigData, ALL);
planData[0] = PointerGetDatum(cpKeyData);
iRetValue = SPI_execp(pplan, planData, NULL, 1);
if (cpKeyData != 0)
SPI_pfree(cpKeyData);
if (iRetValue != SPI_OK_INSERT)
{
elog(NOTICE, "Error inserting row in pendingDelete");
return -1;
}
#if defined DEBUG_OUTPUT
elog(NOTICE, "Insert successful");
#endif
return 0;
}
/**
* Packages the data in tTupleData into a string of the format
* FieldName='value text' where any quotes inside of value text
* are escaped with a backslash and any backslashes in value text
* are esacped by a second back slash.
*
* tTupleDesc should be a description of the tuple stored in
* tTupleData.
*
* eFieldUsage specifies which fields to use.
* PRIMARY implies include only primary key fields.
* NONPRIMARY implies include only non-primary key fields.
* ALL implies include all fields.
*/
char *
packageData(HeapTuple tTupleData, TupleDesc tTupleDesc,
TriggerData *tpTrigData,
enum FieldUsage eKeyUsage)
{
int iNumCols;
int2vector *tpPKeys = NULL;
int iColumnCounter;
char *cpDataBlock;
int iDataBlockSize;
int iUsedDataBlock;
iNumCols = tTupleDesc->natts;
if (eKeyUsage != ALL)
{
tpPKeys = getPrimaryKey(tpTrigData->tg_relation->rd_id);
if (tpPKeys == NULL)
return NULL;
}
#if defined DEBUG_OUTPUT
if (tpPKeys != NULL)
elog(NOTICE, "Have primary keys");
#endif
cpDataBlock = SPI_palloc(BUFFER_SIZE);
iDataBlockSize = BUFFER_SIZE;
iUsedDataBlock = 0; /* To account for the null */
for (iColumnCounter = 1; iColumnCounter <= iNumCols; iColumnCounter++)
{
int iIsPrimaryKey;
int iPrimaryKeyIndex;
char *cpUnFormatedPtr;
char *cpFormatedPtr;
char *cpFieldName;
char *cpFieldData;
if (eKeyUsage != ALL)
{
/* Determine if this is a primary key or not. */
iIsPrimaryKey = 0;
for (iPrimaryKeyIndex = 0; (*tpPKeys)[iPrimaryKeyIndex] != 0;
iPrimaryKeyIndex++)
{
if ((*tpPKeys)[iPrimaryKeyIndex] == iColumnCounter)
{
iIsPrimaryKey = 1;
break;
}
}
if (iIsPrimaryKey ? (eKeyUsage != PRIMARY) : (eKeyUsage != NONPRIMARY))
{
/**
* Don't use.
*/
#if defined DEBUG_OUTPUT
elog(NOTICE, "Skipping column");
#endif
continue;
}
} /* KeyUsage!=ALL */
cpFieldName = DatumGetPointer(NameGetDatum(&tTupleDesc->attrs
[iColumnCounter - 1]->attname));
#if defined DEBUG_OUTPUT
elog(NOTICE, "FieldName: %s", cpFieldName);
#endif
while (iDataBlockSize - iUsedDataBlock < strlen(cpFieldName) + 6)
{
cpDataBlock = SPI_repalloc(cpDataBlock, iDataBlockSize + BUFFER_SIZE);
iDataBlockSize = iDataBlockSize + BUFFER_SIZE;
}
sprintf(cpDataBlock + iUsedDataBlock, "\"%s\"=", cpFieldName);
iUsedDataBlock = iUsedDataBlock + strlen(cpFieldName) + 3;
cpFieldData = SPI_getvalue(tTupleData, tTupleDesc, iColumnCounter);
cpUnFormatedPtr = cpFieldData;
cpFormatedPtr = cpDataBlock + iUsedDataBlock;
if (cpFieldData != NULL)
{
*cpFormatedPtr = '\'';
iUsedDataBlock++;
cpFormatedPtr++;
}
else
{
sprintf(cpFormatedPtr," ");
iUsedDataBlock++;
cpFormatedPtr++;
continue;
}
#if defined DEBUG_OUTPUT
elog(NOTICE, "FieldData: %s", cpFieldData);
elog(NOTICE, "Starting format loop");
#endif
while (*cpUnFormatedPtr != 0)
{
while (iDataBlockSize - iUsedDataBlock < 2)
{
cpDataBlock = SPI_repalloc(cpDataBlock, iDataBlockSize + BUFFER_SIZE);
iDataBlockSize = iDataBlockSize + BUFFER_SIZE;
cpFormatedPtr = cpDataBlock + iUsedDataBlock;
}
if (*cpUnFormatedPtr == '\\' || *cpUnFormatedPtr == '\'')
{
*cpFormatedPtr = '\\';
cpFormatedPtr++;
iUsedDataBlock++;
}
*cpFormatedPtr = *cpUnFormatedPtr;
cpFormatedPtr++;
cpUnFormatedPtr++;
iUsedDataBlock++;
}
SPI_pfree(cpFieldData);
while (iDataBlockSize - iUsedDataBlock < 3)
{
cpDataBlock = SPI_repalloc(cpDataBlock, iDataBlockSize + BUFFER_SIZE);
iDataBlockSize = iDataBlockSize + BUFFER_SIZE;
cpFormatedPtr = cpDataBlock + iUsedDataBlock;
}
sprintf(cpFormatedPtr, "' ");
iUsedDataBlock = iUsedDataBlock + 2;
#if defined DEBUG_OUTPUT
elog(NOTICE, "DataBlock: %s", cpDataBlock);
#endif
} /* for iColumnCounter */
if (tpPKeys != NULL)
SPI_pfree(tpPKeys);
#if defined DEBUG_OUTPUT
elog(NOTICE, "Returning: DataBlockSize:%d iUsedDataBlock:%d",iDataBlockSize,
iUsedDataBlock);
#endif
memset(cpDataBlock + iUsedDataBlock, 0, iDataBlockSize - iUsedDataBlock);
return cpDataBlock;
}
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