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postgresql/contrib/dbmirror/pending.c

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/****************************************************************************
* pending.c
* $Id: pending.c,v 1.1 2002/06/23 21:58:08 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.
* Released under the GNU Public License version 2. See COPYING.
*
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*
***************************************************************************/
#include <executor/spi.h>
#include <commands/trigger.h>
#include <postgres.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
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;
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);
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(tblname,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_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 defined DEBUG_OUTPUT
elog(NOTICE,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 SUCCESFULL");
#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 SUCCESFULL");
#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,cpFieldName);
#endif
while(iDataBlockSize - iUsedDataBlock < strlen(cpFieldName) +4) {
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 {
*cpFormatedPtr=' ';
iUsedDataBlock++;
cpFormatedPtr++;
continue;
}
#if defined DEBUG_OUTPUT
elog(NOTICE,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,cpDataBlock);
#endif
} /* for iColumnCounter */
if(tpPKeys!=NULL) {
SPI_pfree(tpPKeys);
}
#if defined DEBUG_OUTPUT
elog(NOTICE,"Returning");
#endif
memset(cpDataBlock + iUsedDataBlock,0,iDataBlockSize - iUsedDataBlock);
return cpDataBlock;
}
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