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authorIgor Babaev <igor@askmonty.org>2019-02-12 22:56:24 -0800
committerIgor Babaev <igor@askmonty.org>2019-02-12 22:56:24 -0800
commit27c3abde3071ad2010cbcda5b07435ad15364a70 (patch)
tree0d4e4066762076beaba6c8d2e774202be7146e2c /storage/federatedx
parent17d00d9a94da2c2b57fc7cf75036d92ee6dc9298 (diff)
downloadmariadb-git-27c3abde3071ad2010cbcda5b07435ad15364a70.tar.gz
MDEV-17096 Pushdown of simple derived tables to storage engines
MDEV-17631 select_handler for a full query pushdown Added comments and file headers for files introduced in these tasks.
Diffstat (limited to 'storage/federatedx')
-rw-r--r--storage/federatedx/federatedx_pushdown.cc19
1 files changed, 19 insertions, 0 deletions
diff --git a/storage/federatedx/federatedx_pushdown.cc b/storage/federatedx/federatedx_pushdown.cc
index 906d87c29ce..2bcee943308 100644
--- a/storage/federatedx/federatedx_pushdown.cc
+++ b/storage/federatedx/federatedx_pushdown.cc
@@ -16,6 +16,25 @@
/* !!! For inclusion into ha_federatedx.cc */
+
+/*
+ This is a quick a dirty implemention of the derived_handler and select_handler
+ interfaces to be used to push select queries and the queries specifying
+ derived tables into FEDERATEDX engine.
+ The functions
+ create_federatedx_derived_handler and
+ create_federatedx_select_handler
+ that return the corresponding interfaces for pushdown capabilities do
+ not check a lot of things. In particular they do not check that the tables
+ of the pushed queries belong to the same foreign server.
+
+ The implementation is provided purely for testing purposes.
+ The pushdown capabilities are enabled by turning on the plugin system
+ variable federated_pushdown:
+ set global federated_pushdown=1;
+*/
+
+
static derived_handler*
create_federatedx_derived_handler(THD* thd, TABLE_LIST *derived)
{