|
|
You're in the
sql server full text search
group:CONTAINS and LIKE
sql server full text search:
Thanks a lot! It will do a clustered index scan. this is what it looks like. StmtText ---------------------------------------------------------------------------- ------------------------- SELECT * from authors WHERE CONTAINS( *, 'keyworkd') OR au_lname LIKE '%keyworkd%' (1 row(s) affected) StmtText ---------------------------------------------------------------------------- ---------------------------------------------------------------------------- ---------------- |--Filter(WHERE:(like([authors].[au_lname], '%keyworkd%', NULL) OR [Expr1004])) |--Nested Loops(Left Semi Join, WHERE:(like([authors].[au_lname], '%keyworkd%', NULL))OUTER REFERENCES:([authors].[au_id]), DEFINE:([Expr1004] = [PROBE VALUE])) |--Clustered Index Scan(OBJECT:([pubs].[dbo].[authors].[UPKCL_auidind])) |--Filter(WHERE:([authors].[au_id]=[FULLTEXT:authors].[KEY])) |--Table Spool |--Remote Scan(OBJECT:(CONTAINS)) (6 row(s) affected)
I didn't think you were being serious before.
Basically it does a remote scan of the full text catalog (|--Remote Scan(OBJECT:(CONTAINS))), it then spools this data locally and does a join against the authors table - scanning the au_id column using the auidind index (this is a clustered index scan) Scan(OBJECT:([pubs].[dbo].[authors].[UPKCL_auidind])) |--Filter(WHERE:([authors].[au_id]=[FULLTEXT:authors].[KEY])) |--Table Spool It then does a nested loop against the authors table using the join (Left Semi Join, WHERE:(like([authors].[au_lname], '%keyworkd%', NULL)) and filters the results. Put this query in query analyzer and hit ctrl - L and you can see it for yourself. -- Hilary Cotter Looking for a SQL Server replication book? http://www.nwsu.com/0974973602.html Looking for a FAQ on Indexing Services/SQL FTS http://www.indexserverfaq.com [quoted text, click to view] "Matias Woloski" <woloski@NOSPAMsion.com> wrote in message news:OJYMB6lVFHA.1328@tk2msftngp13.phx.gbl... > Hillary, would you mind doing a small explanation on this post? > Thanks a lot! > > It will do a clustered index scan. this is what it looks like. > > > StmtText > -------------------------------------------------------------------------- -- > ------------------------- > SELECT * from authors > WHERE > CONTAINS( *, 'keyworkd') > OR > au_lname LIKE '%keyworkd%' > > (1 row(s) affected) > > StmtText > -------------------------------------------------------------------------- -- > -------------------------------------------------------------------------- -- > ---------------- > |--Filter(WHERE:(like([authors].[au_lname], '%keyworkd%', NULL) OR > [Expr1004])) > |--Nested Loops(Left Semi Join, WHERE:(like([authors].[au_lname], > '%keyworkd%', NULL))OUTER REFERENCES:([authors].[au_id]), DEFINE:([Expr1004] > = [PROBE VALUE])) > |--Clustered Index > Scan(OBJECT:([pubs].[dbo].[authors].[UPKCL_auidind])) > |--Filter(WHERE:([authors].[au_id]=[FULLTEXT:authors].[KEY])) > |--Table Spool > |--Remote Scan(OBJECT:(CONTAINS)) > > (6 row(s) affected) > > >
Thanks Hilary for introducing me into this.
Now, I see the execution plan for this query and I see that 87% of the query is the remote scan (contains). I was concerned about the perf impact of having CONTAINS and LIKE both together and it seems that is minimal. What if I have 100k records? How the clustered index (like expr) would perform? How compared to a query which only does a remote scan? Thanks again for your help, Matias [quoted text, click to view] "Hilary Cotter" <hilary.cotter@gmail.com> wrote in message news:uHajidvVFHA.2768@tk2msftngp13.phx.gbl... >I didn't think you were being serious before. > > Basically it does a remote scan of the full text catalog (|--Remote > Scan(OBJECT:(CONTAINS))), it then spools this data locally and does a join > against the authors table - scanning the au_id column using the auidind > index (this is a clustered index scan) > > Scan(OBJECT:([pubs].[dbo].[authors].[UPKCL_auidind])) > |--Filter(WHERE:([authors].[au_id]=[FULLTEXT:authors].[KEY])) > |--Table Spool > > It then does a nested loop against the authors table using the join (Left > Semi Join, WHERE:(like([authors].[au_lname], '%keyworkd%', NULL)) > > and filters the results. > > Put this query in query analyzer and hit ctrl - L > > and you can see it for yourself. > > > > -- > Hilary Cotter > Looking for a SQL Server replication book? > http://www.nwsu.com/0974973602.html > > Looking for a FAQ on Indexing Services/SQL FTS > http://www.indexserverfaq.com > > "Matias Woloski" <woloski@NOSPAMsion.com> wrote in message > news:OJYMB6lVFHA.1328@tk2msftngp13.phx.gbl... >> Hillary, would you mind doing a small explanation on this post? >> Thanks a lot! >> >> It will do a clustered index scan. this is what it looks like. >> >> >> StmtText >> -------------------------------------------------------------------------- > -- >> ------------------------- >> SELECT * from authors >> WHERE >> CONTAINS( *, 'keyworkd') >> OR >> au_lname LIKE '%keyworkd%' >> >> (1 row(s) affected) >> >> StmtText >> -------------------------------------------------------------------------- > -- >> -------------------------------------------------------------------------- > -- >> ---------------- >> |--Filter(WHERE:(like([authors].[au_lname], '%keyworkd%', NULL) OR >> [Expr1004])) >> |--Nested Loops(Left Semi Join, WHERE:(like([authors].[au_lname], >> '%keyworkd%', NULL))OUTER REFERENCES:([authors].[au_id]), > DEFINE:([Expr1004] >> = [PROBE VALUE])) >> |--Clustered Index >> Scan(OBJECT:([pubs].[dbo].[authors].[UPKCL_auidind])) >> |--Filter(WHERE:([authors].[au_id]=[FULLTEXT:authors].[KEY])) > >> |--Table Spool >> |--Remote Scan(OBJECT:(CONTAINS)) >> >> (6 row(s) affected) >> >> >> > >
The nested loop is changed to a merge join
|--Filter(WHERE:(like([fulltext].[charcol], '%keyworkd%', NULL) OR [Expr1004])) |--Merge Join(Left Semi Join, MERGE:([fulltext].[pk])=([FULLTEXT:fulltext].[KEY]), RESIDUAL:([fulltext].[pk]=[FULLTEXT:fulltext].[KEY]) OR like([fulltext].[charcol], '%keyworkd%', NULL)) |--Clustered Index Scan(OBJECT:([pubs].[dbo].[fulltext].[primarykey]), ORDERED FORWARD) |--Sort(ORDER BY:([FULLTEXT:fulltext].[KEY] ASC)) |--Remote Scan(OBJECT:(CONTAINS)) (5 row(s) affected) -- Hilary Cotter Looking for a SQL Server replication book? http://www.nwsu.com/0974973602.html Looking for a FAQ on Indexing Services/SQL FTS http://www.indexserverfaq.com [quoted text, click to view] "Matias Woloski" <woloski@NOSPAMsion.com> wrote in message news:uZPS3KxVFHA.2496@TK2MSFTNGP10.phx.gbl... > Thanks Hilary for introducing me into this. > > Now, I see the execution plan for this query and I see that 87% of the query > is the remote scan (contains). > > I was concerned about the perf impact of having CONTAINS and LIKE both > together and it seems that is minimal. > > What if I have 100k records? How the clustered index (like expr) would > perform? How compared to a query which only does a remote scan? > > Thanks again for your help, > Matias > > > "Hilary Cotter" <hilary.cotter@gmail.com> wrote in message > news:uHajidvVFHA.2768@tk2msftngp13.phx.gbl... > >I didn't think you were being serious before. > > > > Basically it does a remote scan of the full text catalog (|--Remote > > Scan(OBJECT:(CONTAINS))), it then spools this data locally and does a join > > against the authors table - scanning the au_id column using the auidind > > index (this is a clustered index scan) > > > > Scan(OBJECT:([pubs].[dbo].[authors].[UPKCL_auidind])) > > |--Filter(WHERE:([authors].[au_id]=[FULLTEXT:authors].[KEY])) > > |--Table Spool > > > > It then does a nested loop against the authors table using the join (Left > > Semi Join, WHERE:(like([authors].[au_lname], '%keyworkd%', NULL)) > > > > and filters the results. > > > > Put this query in query analyzer and hit ctrl - L > > > > and you can see it for yourself. > > > > > > > > -- > > Hilary Cotter > > Looking for a SQL Server replication book? > > http://www.nwsu.com/0974973602.html > > > > Looking for a FAQ on Indexing Services/SQL FTS > > http://www.indexserverfaq.com > > > > "Matias Woloski" <woloski@NOSPAMsion.com> wrote in message > > news:OJYMB6lVFHA.1328@tk2msftngp13.phx.gbl... > >> Hillary, would you mind doing a small explanation on this post? > >> Thanks a lot! > >> > >> It will do a clustered index scan. this is what it looks like. > >> > >> > >> StmtText > >> ------------------------------------------------------------------------- - > > -- > >> ------------------------- > >> SELECT * from authors > >> WHERE > >> CONTAINS( *, 'keyworkd') > >> OR > >> au_lname LIKE '%keyworkd%' > >> > >> (1 row(s) affected) > >> > >> StmtText > >> ------------------------------------------------------------------------- - > > -- > >> ------------------------------------------------------------------------- - > > -- > >> ---------------- > >> |--Filter(WHERE:(like([authors].[au_lname], '%keyworkd%', NULL) OR > >> [Expr1004])) > >> |--Nested Loops(Left Semi Join, WHERE:(like([authors].[au_lname], > >> '%keyworkd%', NULL))OUTER REFERENCES:([authors].[au_id]), > > DEFINE:([Expr1004] > >> = [PROBE VALUE])) > >> |--Clustered Index > >> Scan(OBJECT:([pubs].[dbo].[authors].[UPKCL_auidind])) > >> |--Filter(WHERE:([authors].[au_id]=[FULLTEXT:authors].[KEY])) > > > >> |--Table Spool > >> |--Remote Scan(OBJECT:(CONTAINS)) > >> > >> (6 row(s) affected) > >> > >> > >> > > > > > >
Don't see what you're looking for? Try a search.
|
June 2003
July 2003
August 2003
September 2003
October 2003
November 2003
December 2003
January 2004
February 2004
March 2004
April 2004
May 2004
June 2004
July 2004
August 2004
September 2004
October 2004
November 2004
December 2004
January 2005
February 2005
March 2005
April 2005
May 2005
June 2005
July 2005
August 2005
September 2005
October 2005
November 2005
December 2005
January 2006
February 2006
March 2006
April 2006
May 2006
June 2006
July 2006
August 2006
September 2006
October 2006
November 2006
December 2006
January 2007
February 2007
March 2007
April 2007
May 2007
June 2007
July 2007
August 2007
September 2007
October 2007
November 2007
| home · blog · groups | Questions? Comments? Contact the dn |