Thanks Suresh.
Best regards Yuan -----Original Message----- From: Suresh Subbiah <[email protected]> Sent: Wednesday, October 17, 2018 11:04 PM To: [email protected] Subject: [外部邮件] Re: How to get vsbb_scan plan? Hi Yuan, Yes, nested join on primary key is the only case I can think of too. We need a full key match on the predicate, there also has to be multiple requests so that the result contains more than one row, even with a full key predicate. I think nested join on primary key is the only case. Here is a quick example create table tw (a int not null primary key); >>control query shape nested_join(cut,cut) ; --- SQL operation complete. >>prepare s1 from select * from tw a, tw b where a.a = b.a ; --- SQL command prepared. >>explain options 'f' s1 ; LC RC OP OPERATOR OPT DESCRIPTION CARD ---- ---- ---- -------------------- -------- -------------------- --------- 3 . 4 root 1.50E+004 1 2 3 nested_join 1.50E+004 . . 2 trafodion_vsbb_scan TW 1.00E+000 . . 1 trafodion_scan TW 1.50E+004 --- SQL operation complete. The method that determines what gets printed in explain is shown below. Thank you Suresh const NAString HbaseAccess::getText() const { NAString op(CmpCommon::statementHeap()); NAString tname(getTableName().getText(),CmpCommon::statementHeap()); NAString sampleOpt(CmpCommon::statementHeap()); if (isSampleScan()) sampleOpt = "sample_"; if (getIndexDesc() == NULL OR getIndexDesc()->isClusteringIndex()) { if (isSeabaseTable()) { if (uniqueRowsetHbaseOper()) (op += "trafodion_vsbb_") += sampleOpt += "scan "; else (op += "trafodion_") += sampleOpt += "scan "; } else (op += "hbase_") += sampleOpt += "scan "; } else { if (isSeabaseTable()) (op += "trafodion_index_") += sampleOpt += "scan "; else (op += "hbase_index_") += sampleOpt += "scan "; tname = getIndexDesc()->getIndexName().getQualifiedNameAsString() + "(" + tname + ")"; } if (getReverseScan()) op += NAString("rev "); return op + tname; } On Sat, Oct 13, 2018 at 11:23 AM Liu, Yuan (Yuan) <[email protected]> wrote: > Hi trafodioneers, > > > > For scan operator, we have trafodion scan, index scan and vsbbscan. > > In which scenarios can we get a vsbb scan? Nested join on primary key? > > > > Best regards > > > > 刘源（Yuan） > > *上海易鲸捷信息技术有限公司* <http://www.esgyn.cn/> > > 地址：上海市浦东新区金科路2889号长泰广场A座603 > > 手机：13671935540 > > 邮箱：[email protected] > > [image: 易鲸捷logo中文 - 副本] > > >
