// append an ascii-version of Join into cachewa.qryText_
void Join::generateCacheKey(CacheWA &cwa) const
{
RelExpr::generateCacheKeyNode(cwa);
if (isNaturalJoin_) {
cwa += " natj ";
}
ItemExpr *pred = joinPredTree_ ? joinPredTree_ :
joinPred_.rebuildExprTree();
if (pred) {
cwa += " joinPred:";
pred->generateCacheKey(cwa);
}
generateCacheKeyForKids(cwa);
}
// append an ascii-version of GroupByAgg into cachewa.qryText_
void GroupByAgg::generateCacheKey(CacheWA &cwa) const
{
RelExpr::generateCacheKey(cwa);
// group by col/expr is an important part of the key
ItemExpr *grpExpr = groupExprTree_ ? groupExprTree_ :
groupExpr_.rebuildExprTree(ITM_ITEM_LIST);
if (grpExpr) {
cwa += " gBy:";
if (isRollup())
{
cwa += " roll:";
ItemExpr * ie = rollupGroupExprList().rebuildExprTree(ITM_ITEM_LIST);
if (ie)
{
ie->generateCacheKey(cwa);
}
}
grpExpr->generateCacheKey(cwa);
}
}
// append an ascii-version of Tuple into cachewa.qryText_
void Tuple::generateCacheKey(CacheWA &cwa) const
{
// Do not call RelExpr::generateCacheKey(cwa) here because it's redundant.
// It does the same things as the code below. RelExpr::generateCacheKey()
// calls Tuple::getText() which has logic similar to the following code.
ItemExpr *tExpr = tupleExprTree() ? tupleExprTree() :
tupleExpr_.rebuildExprTree();
if (tExpr) {
cwa += " tupExpr:";
tExpr->generateCacheKey(cwa);
}
else {
RelExpr::generateCacheKey(cwa);
}
}
// append an ascii-version of Insert into cachewa.qryText_
void Insert::generateCacheKey(CacheWA &cwa) const
{
GenericUpdate::generateCacheKey(cwa);
if (insertColTree_) {
cwa += " insCol:";
insertColTree_->generateCacheKey(cwa);
}
// order by clause is important
ItemExpr *orderBy = orderByTree_ ? orderByTree_ :
reqdOrder_.rebuildExprTree();
if (orderBy) {
cwa += " order:";
orderBy->generateCacheKey(cwa);
}
const NATable *tbl;
if (cwa.getPhase() >= CmpMain::BIND &&
getTableDesc() && (tbl=getTableDesc()->getNATable()) != NULL) {
// If PARTITION clause has been used we must reflect that in the key.
if (tbl->isPartitionNameSpecified()) {
cwa += " partition:";
cwa += tbl->getClusteringIndex()->getFileSetName().getQualifiedNameAsString().data();
}
// If PARTITION range has been used we must reflect that in the key.
else if (tbl->isPartitionRangeSpecified()) {
cwa += " partition:";
char str[100];
sprintf(str, " from %d to %d",
tbl->getExtendedQualName().getPartnClause().getBeginPartitionNumber() ,
tbl->getExtendedQualName().getPartnClause().getEndPartitionNumber());
cwa += str;
}
}
if (isUpsert())
{
cwa += " upsert:";
}
}
// append an ascii-version of RelExpr node into cachewa.qryText_
void RelExpr::generateCacheKeyNode(CacheWA &cwa) const
{
// emit any "[firstn_sorted]" modifier
if (firstNRows_ != -1) {
char firstN[40];
convertInt64ToAscii(((RelExpr*)this)->getFirstNRows(), firstN);
cwa += firstN;
cwa += " ";
}
// emit other "significant" parts of RelExpr
cwa += getText();
ItemExpr *pred = selPredTree() ? selPredTree() :
getSelectionPred().rebuildExprTree();
if (pred) {
cwa += " selPred:";
pred->generateCacheKey(cwa);
}
// make any optimizer hints part of the postbinder cache key so that
// 2 cacheable queries with different optimizer hints do not match
if (hint_) {
CollIndex x, cnt=hint_->indexCnt();
if (cnt > 0) {
cwa += " xhint:";
for (x = 0; x < cnt; x++) {
cwa += (*hint_)[x].data();
cwa += ",";
}
}
char str[100];
if (hint_->hasCardinality()) {
sprintf(str, "card:%g", hint_->getCardinality());
cwa += str;
}
if (hint_->hasSelectivity()) {
sprintf(str, ",sel:%g", hint_->getSelectivity());
cwa += str;
}
}
}
// append an ascii-version of RelRoot into cachewa.qryText_
void RelRoot::generateCacheKey(CacheWA &cwa) const
{
RelExpr::generateCacheKey(cwa);
ItemExpr *cExpr = compExprTree_ ? compExprTree_ :
compExpr_.rebuildExprTree();
if (cExpr) {
// append any select list into cache key
cwa += " cExpr:";
cExpr->generateCacheKey(cwa);
// reflect any "[first n]"
cwa += ((RelRoot*)this)->needFirstSortedRows() ? " 1stN" : " ";
// Should the select_list aliases be a part of the cache key?
// Their not affecting the compiled plan argues for their exclusion.
// Their affecting sqlci's expected output argues for their inclusion.
RETDesc *rDesc = getRETDesc();
CollIndex degree, x;
if (rDesc && (degree=rDesc->getDegree()) > 0) {
cwa += " sla:";
for (x = 0; x < degree; x++){
cwa += rDesc->getColRefNameObj(x).getColName().data();
cwa += " ";
}
// fix 0-061115-0532 (query cache didn't handle select with embedded
// update correctly). New/Old corr. names are recorded for embedded
// updates here for exact match. This is important because otherwise
// a reuse of a query returning the old/new version of values for
// a query requesting new/old version is totally possible and
// unacceptable.
//
// Sample embedded update queries
// select * from (update tab1 set x = x + 1 where x > 1 return new.*) y;
// select * from (update tab1 set x = x + 1 where x > 1 return new.x, old.y) y;
//
if ( cwa.isUpdate() && isTrueRoot() == FALSE ) {
cwa += " corrNamTok:";
cwa += rDesc->getBindWA()->getCorrNameTokens();
}
}
}
// order by clause is important
ItemExpr *orderBy = orderByTree_ ? orderByTree_ :
reqdOrder_.rebuildExprTree();
if (orderBy) {
cwa += " order:";
orderBy->generateCacheKey(cwa);
}
// statement-level access type & lock mode are important for multiuser
// applications. both are reflected in the stmt-level and/or context-wide
// TransMode. So, we mimic RelRoot::codeGen logic here: "copy the current
// context-wide TransMode, then overlay with this stmt's 'FOR xxx ACCESS'
// setting, if any".
TransMode tmode;
tmode.updateTransMode(CmpCommon::transMode());
StmtLevelAccessOptions &opts = ((RelRoot*)this)->accessOptions();
if (opts.accessType() != ACCESS_TYPE_NOT_SPECIFIED_) {
tmode.updateAccessModeFromIsolationLevel
(TransMode::ATtoIL(opts.accessType()));
tmode.setStmtLevelAccessOptions();
}
if (isTrueRoot()) {
// these are needed by Javier's qc stats virtual tbl interface
cwa.setIsoLvl(tmode.getIsolationLevel());
cwa.setAccessMode(tmode.getAccessMode());
cwa.setAutoCommit(tmode.getAutoCommit());
cwa.setFlags(tmode.getFlags());
cwa.setRollbackMode(tmode.getRollbackMode());
cwa.setAutoabortInterval(tmode.getAutoAbortIntervalInSeconds());
cwa.setMultiCommit(tmode.getMultiCommit());
}
// needed to distinguish these queries and avoid a false hit
// select * from (delete from t where a=2) as t;
// select * from (delete from t where a=2 for SKIP CONFLICT ACCESS) as t;
char mode[40];
str_itoa(tmode.getIsolationLevel(), mode); cwa += " il:"; cwa += mode;
str_itoa(tmode.getAccessMode(), mode); cwa += " am:"; cwa += mode;
// Solution: 10-060418-5903
str_itoa(cwa.getIsoLvlForUpdates(), mode); cwa += " ilu:"; cwa += mode;
str_itoa(tmode.getAutoCommit(), mode); cwa += " ac:"; cwa += mode;
str_itoa(tmode.getFlags(), mode); cwa += " fl:"; cwa += mode;
str_itoa(tmode.getRollbackMode(), mode); cwa += " rm:"; cwa += mode;
str_itoa(tmode.getAutoAbortIntervalInSeconds(), mode); cwa += " ai:"; cwa += mode;
str_itoa(tmode.getMultiCommit(), mode); cwa += " mc:"; cwa += mode;
if (opts.lockMode() != LOCK_MODE_NOT_SPECIFIED_) {
// need to distinguish these queries and avoid a false hit
// select * from t in share mode;
// select * from t in exclusive mode;
str_itoa(opts.lockMode(), mode); cwa += " lm:"; cwa += mode;
}
// updatableSelect_ is essential. Otherwise, queries like
// "select * from t" and "select * from t for update" can confuse
// query caching into a false hit, causing fullstack/test051 to fail.
if (updatableSelect_) {
cwa += " 4updt ";
}
// for update of col [,col]... clause is important
ItemExpr *updCol = updateColTree_ ? updateColTree_ :
updateCol_.rebuildExprTree();
if (updCol) {
cwa += " updCol:";
updCol->generateCacheKey(cwa);
}
// making the CQS part of the key is more efficient than calling
// CompilerEnv::changeEnv() in ControlDB::setRequiredShape()
if (reqdShape_) {
reqdShape_->unparse(cwa.reqdShape_);
}
}
// append an ascii-version of GenericUpdate into cachewa.qryText_
void GenericUpdate::generateCacheKey(CacheWA& cwa) const
// NB: This comment applies to all generateCacheKey methods.
// generateCacheKey is used to generate a string representation s of the
// "parameterized" query. Since this string s is used by QCache::lookUp
// to determine if a query is in the cache, it is essential that:
// (1) two different queries have different string representations
// (2) two queries that differ only in their query literals should
// have the same string representations
// One possible implementation of generateCacheKey is to use the query's
// original query text. But, original query text does not satisfy (2).
// To get (2), we call generateCacheKey() from RelRoot::normalizeForCache
// which, by definition, replaced query literals with constant parameters.
// However, generateCacheKey must also satisfy (1). generateCacheKey must
// generate two different strings for two logically different queries.
//
// To satisfy requirements (1) and (2), generateCacheKey and
// normalizeForCache must be in sync -- every user-specified expr that
// generateCacheKey emits into cwa.qryText_ must be examined by
// normalizeForCache for possible replacement of any literal there into
// a constant parameter.
//
// In order for the literal-into-constantparameter replacement to be safe,
// isCacheableExpr must visit all user-specified exprs to make sure that
// only constants that can be safely cast into the query's target types
// are considered cacheable. For example, given this update query
// update t set a = 'xyz' where pk = 1;
// isCacheableeExpr, normalizeForCache, and generateCacheKey must cooperate
// so that:
// 1) isCacheableExpr rejects the query as noncacheble if 'xyz' cannot be
// safely cast into a's target type, eg, 'xyz' may be too long if a's
// type is char(1).
// 2) normalizeForCache must visit and replace both 'xyz' and 1 with
// appropriate constant parameters.
// 3) generateCacheKey must emit some string representation of the
// parameterized query, eg, "update t set a = % where pk = %".
// generateCacheKey can emit more stuff, eg, internally specified
// begin/end-key predicates, but it must emit a string representation
// of all user-specified parts of the query.
{
// append to cwa.qryText_ GenericUpdate's "essential" data members
RelExpr::generateCacheKey(cwa);
// An extension of the fix to 10-010618-3505, 10-010619-3515:
// for "after bind" Insert/Update/Delete queries, include table's
// RedefTime into cwa.qryText_ to make sure we get a cache hit only on
// query that reference table(s) that have not changed since the query's
// addition to the cache. The queries that reference altered table(s)
// will never be hit again and will eventually age out of the cache.
// This is not strictly necessary, but it speeds up the processing
// of insert/update/delete queries on altered tables.
const NATable *tbl;
if (cwa.getPhase() >= CmpMain::BIND &&
getTableDesc() && (tbl=getTableDesc()->getNATable()) != NULL) {
char redefTime[40];
convertInt64ToAscii(tbl->getRedefTime(), redefTime);
cwa += " redef:";
cwa += redefTime;
}
ItemExpr *newExpr = newRecExprTree_ ? newRecExprTree_ :
newRecExpr_.rebuildExprTree(ITM_ITEM_LIST);
if (newExpr) {
cwa += " newRecExpr:";
newExpr->generateCacheKey(cwa);
}
// make sure cache key can distinguish these 2 queries:
// prepare s from select * from (update t042qT8 set b=7 where a=2) as t;
// prepare s from select * from (update t042qT8 set b=7 set on rollback c=2
// where a=2) as t;
ItemExpr *setOnRollback;
if (newRecBeforeExpr_.entries() > 0 &&
(setOnRollback=newRecBeforeExpr_.rebuildExprTree(ITM_ITEM_LIST))) {
cwa += " setOnRollback:";
setOnRollback->generateCacheKey(cwa);
}
ItemExpr *execPred = executorPredTree_ ? executorPredTree_ :
executorPred_.rebuildExprTree();
if (execPred) {
cwa += " execPred:";
execPred->generateCacheKey(cwa);
}
// MVs --
// The NOLOG parameter is essential.
if (isNoLogOperation()) {
cwa += " NOLOG";
}
// "current of cursor/hostvar" is essential
if (currOfCursorName_) {
currOfCursorName_->generateCacheKey(cwa);
}
// not sure if the following are essential, but better to be safe &
// slightly inefficient than to deliver a false hit (ie, wrong plan)
cwa += mtsStatement_ ? "m1" : "m0";
cwa += noFlow_ ? "n1" : "n0";
cwa += noRollback_ ? "o1" : "o0";
cwa += noCheck_ ? "nc" : "dc";
// not sure if the following are essential, but we don't know how
// to quickly & cheaply include them into our cachekey:
// updatedTableName_, tabId_, updateToSelectMap_, indexDesc_,
// newRecExprArray_, usedColumns_, newRecBeforeExpr_,
// newRecBeforeExprArray_, usedBeforeColumns_, potentialOutputs_
// indexNumberArray_, scanIndexDesc_, rowsAffected_, stoi_,
// oldToNewMap_
// The following data members are not "essential" to generateCacheKey
// (at least "after bind") because they are either covered by other
// data members (eg, beginKeyPred and endKeyPred_ are covered by the
// selection pred in RelExpr) or they are not yet defined until later
// (eg, after the optimize phase):
// indexNewRecExprArrays_, beginKeyPred_, endKeyPred_,
// pathKeys_, partKeys_, indexBeginKeyPredArray_,
// indexEndKeyPredArray_, checkConstraints_
}