maria-developers team mailing list archive

[Zardosht Kasheff <zardosht@xxxxxxxxx>]

Hello,

I have found an interesting issue with index condition pushdown. I do
not know if it is a bug, or if I am misusing the feature.

I have found that in one scenario, when performing a join, an index
condition is pushed down, but because handler->end_range is not set,
handler_index_cond_check never returns ICP_OUT_OF_RANGE, even though
we are out of range.

Here is the relevant stack trace, I cannot yet send the entire trace
as it may include customer information, and I need to double check it
is ok to send:
#15 0x00002aaac4f33593 in ha_tokudb::index_next_same (this=0x2fb33d8,
buf=0x2fb53b8 "\302\177\254\353/\036", key=0x31b36d0 "Y\001",
keylen=395)
---Type <return> to continue, or q <return> to quit---
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/storage/tokudb/ha_tokudb.cc:4768
#16 0x00000000005e782c in handler::ha_index_next_same (this=0x2fb33d8,
buf=0x2fb53b8 "\302\177\254\353/\036", key=0x31b36d0 "Y\001",
keylen=395)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_class.h:4246
#17 0x000000000065d103 in join_read_next_same (info=0x31b2f68) at
/home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:16929
#18 0x000000000065b54a in sub_select (join=0x319f588,
join_tab=0x31b2eb8, end_of_records=false)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:16142
#19 0x000000000065bb5f in evaluate_join_record (join=0x319f588,
join_tab=0x31b2b98, error=0)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:16342
#20 0x000000000065b628 in sub_select (join=0x319f588,
join_tab=0x31b2b98, end_of_records=false)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:16162
#21 0x000000000065bb5f in evaluate_join_record (join=0x319f588,
join_tab=0x31b2878, error=0)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:16342
#22 0x000000000065b498 in sub_select (join=0x319f588,
join_tab=0x31b2878, end_of_records=false)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:16123
#23 0x000000000065bb5f in evaluate_join_record (join=0x319f588,
join_tab=0x31b2558, error=0)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:16342
#24 0x000000000065b628 in sub_select (join=0x319f588,
join_tab=0x31b2558, end_of_records=false)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:16162
#25 0x000000000065ad52 in do_select (join=0x319f588, fields=0x0,
table=0x31bf368, procedure=0x0)
    at /home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:15793
#26 0x0000000000639c5d in JOIN::exec (this=0x319f588) at
/home/zardosht/maria/mysql-build/mariadb-5.5.28a/sql/sql_select.cc:2396

In this stack, we are performing an index_next_same, and a condition
has been pushed down. When we call handler_index_cond_check. we always
get ICP_NO_MATCH and never get ICP_OUT_OF_RANGE, even though we go
past the key that we should be retrieving.

Is this by design? Is this a bug?

Thanks
-Zardosht