// 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_);
}
}
