[evolution-data-server/sqlite-refactor] Experimental changes...

[Tristan Van Berkom <tvb src gnome org>]

commit d4c5f744a89637f1f67a022fd8b3cbaf765721d1
Author: Tristan Van Berkom <tristanvb openismus com>
Date:   Sun Dec 1 04:56:25 2013 +0900

    Experimental changes...

 addressbook/libedata-book/e-book-sqlite.c |   28 ++++++++++++++++++++++++----
 1 files changed, 24 insertions(+), 4 deletions(-)
---
diff --git a/addressbook/libedata-book/e-book-sqlite.c b/addressbook/libedata-book/e-book-sqlite.c
index 56f33cc..980fda5 100644
--- a/addressbook/libedata-book/e-book-sqlite.c
+++ b/addressbook/libedata-book/e-book-sqlite.c
@@ -2384,10 +2384,16 @@ ebsql_init_aux_tables (EBookSqlite *ebsql,
 
 
                if (success) {
-                       /* Create an index on the 'uid' column, this speeds up inserts on large
-                        * addressbooks, because rows need to be deleted by UID before reinserting
+
+                       /* Create an index on the implied 'uid' column, this is important
+                        * when replacing (modifying) contacts, since we need to remove
+                        * all rows in an auxiliary table which matches a given UID.
+                        *
+                        * This index speeds up the constraint in a statement such as:
+                        *
+                        *   DELETE from email_list WHERE email_list.uid = 'contact uid'
                         */
-                       tmp = g_strconcat ("UIDINDEX",
+                       tmp = g_strconcat ("UID_INDEX",
                                           "_", field->dbname,
                                           "_", ebsql->priv->folderid,
                                           NULL);
@@ -4974,7 +4980,21 @@ ebsql_generate_select (EBookSqlite *ebsql,
                        if ((context->aux_mask & (1 << i)) != 0) {
                                SummaryField *field = &(ebsql->priv->summary_fields[i]);
 
-                               ebsql_string_append_printf (string, " JOIN %Q AS %s ON %s.uid = summary.uid",
+                               /* Note the '+' in the JOIN statement.
+                                *
+                                * This plus makes the uid's index ineligable to participate
+                                * in any indexing.
+                                *
+                                * Without this, the indexes which we prefer for prefix or
+                                * suffix matching in the auxiliary tables are ignored and
+                                * only considered on exact matches.
+                                *
+                                * This is crucial to ensure that the uid index does not
+                                * compete with the value index in constraints such as:
+                                *
+                                *     WHERE email_list.value LIKE "boogieman%"
+                                */
+                               ebsql_string_append_printf (string, " JOIN %Q AS %s ON +%s.uid = summary.uid",
                                                            field->aux_table,
                                                            field->aux_table_symbolic,
                                                            field->aux_table_symbolic);