vendor/subversion/subversion-1.8.8

1 files changed, 48 insertions, 0 deletions

diff --git a/subversion/libsvn_wc/wc-metadata.sql b/subversion/libsvn_wc/wc-metadata.sql
index d2a61613ac62..848293d2cebb 100644
--- a/subversion/libsvn_wc/wc-metadata.sql
+++ b/subversion/libsvn_wc/wc-metadata.sql
@@ -573,6 +573,54 @@ CREATE UNIQUE INDEX I_EXTERNALS_DEFINED ON EXTERNALS (wc_id,
                                                       local_relpath);
 
 /* ------------------------------------------------------------------------- */
+/* This statement provides SQLite with the necessary information about our
+   indexes to make better decisions in the query planner.
+
+   For every interesting index this contains a number of rows where the
+   statistics ar calculated for and then for every column in the index the
+   average number of rows with the same value in all columns left of this
+   column including the column itself.
+
+   See http://www.sqlite.org/fileformat2.html#stat1tab for more details.
+
+   The important thing here is that this tells Sqlite that the wc_id column
+   of the NODES and ACTUAL_NODE table is usually a single value, so queries
+   should use more than one column for index usage.
+
+   The current hints describe NODES+ACTUAL_NODE as a working copy with
+   8000 nodes in 1 a single working copy(=wc_id), 10 nodes per directory
+   and an average of 2 op-depth layers per node.
+
+   The number of integers must be number of index columns + 1, which is
+   verified via the test_schema_statistics() test.
+ */
+-- STMT_INSTALL_SCHEMA_STATISTICS
+ANALYZE sqlite_master; /* Creates empty sqlite_stat1 if necessary */
+
+INSERT OR REPLACE INTO sqlite_stat1(tbl, idx, stat) VALUES
+    ('NODES', 'sqlite_autoindex_NODES_1',               '8000 8000 2 1');
+INSERT OR REPLACE INTO sqlite_stat1(tbl, idx, stat) VALUES
+    ('NODES', 'I_NODES_PARENT',                         '8000 8000 10 2 1');
+/* Tell a lie: We ignore that 99.9% of all moved_to values are NULL */
+INSERT OR REPLACE INTO sqlite_stat1(tbl, idx, stat) VALUES
+    ('NODES', 'I_NODES_MOVED',                          '8000 8000 1 1');
+
+INSERT OR REPLACE INTO sqlite_stat1(tbl, idx, stat) VALUES
+    ('ACTUAL_NODE', 'sqlite_autoindex_ACTUAL_NODE_1',   '8000 8000 1');
+INSERT OR REPLACE INTO sqlite_stat1(tbl, idx, stat) VALUES
+    ('ACTUAL_NODE', 'I_ACTUAL_PARENT',                  '8000 8000 10 1');
+
+INSERT OR REPLACE INTO sqlite_stat1(tbl, idx, stat) VALUES
+    ('LOCK', 'sqlite_autoindex_LOCK_1',                 '100 100 1');
+
+INSERT OR REPLACE INTO sqlite_stat1(tbl, idx, stat) VALUES
+    ('WC_LOCK', 'sqlite_autoindex_WC_LOCK_1',           '100 100 1');
+
+/* sqlite_autoindex_WORK_QUEUE_1 doesn't exist because WORK_QUEUE is
+   a INTEGER PRIMARY KEY AUTOINCREMENT table */
+
+ANALYZE sqlite_master; /* Loads sqlite_stat1 data for query optimizer */
+/* ------------------------------------------------------------------------- */
 
 /* Format 20 introduces NODES and removes BASE_NODE and WORKING_NODE */