sql: Feature flag for in-memory temporary storage.
This CL introduces SqlTempStoreMemory flag, which is intended to be
managed via Finch. When set, the flag causes sql::Database to run a
PRAGMA temp_store=MEMORY [1] query on every opened database.
This approach is intended to approximate the effect of building SQLite
with the SQLITE_TEMP_STORE=3 [2] macro, to measure the memory
consumption impact. Ideally, we'd test the macro directly, but //sql is
a core component of Chrome, so we can't load different versions of it
based on Finch.
[1] https://www.sqlite.org/pragma.html#pragma_temp_store
[2] https://www.sqlite.org/compile.html#temp_store
Bug: 875538
Change-Id: I537d90d763be1100503ed4bd2ada2ee19eb090bb
Reviewed-on: https://chromium-review.googlesource.com/1180530
Reviewed-by: Mark Pearson <[email protected]>
Reviewed-by: Chris Mumford <[email protected]>
Commit-Queue: Victor Costan <[email protected]>
Cr-Commit-Position: refs/heads/master@{#584652}diff --git a/sql/database.cc b/sql/database.cc
index 66bf05b..ffe7c6b 100644
--- a/sql/database.cc
+++ b/sql/database.cc
@@ -33,6 +33,7 @@
#include "sql/database_memory_dump_provider.h"
#include "sql/initialization.h"
#include "sql/meta_table.h"
+#include "sql/sql_features.h"
#include "sql/statement.h"
#include "sql/vfs_wrapper.h"
#include "third_party/sqlite/sqlite3.h"
@@ -1674,6 +1675,12 @@
ignore_result(Execute("PRAGMA locking_mode=EXCLUSIVE"));
}
+ if (base::FeatureList::IsEnabled(features::kSqlTempStoreMemory)) {
+ err = ExecuteAndReturnErrorCode("PRAGMA temp_store=MEMORY");
+ // This operates on in-memory configuration, so it should not fail.
+ DCHECK_EQ(err, SQLITE_OK) << "Failed switching to in-RAM temporary storage";
+ }
+
// http://www.sqlite.org/pragma.html#pragma_journal_mode
// DELETE (default) - delete -journal file to commit.
// TRUNCATE - truncate -journal file to commit.
@@ -1681,7 +1688,7 @@
// TRUNCATE should be faster than DELETE because it won't need directory
// changes for each transaction. PERSIST may break the spirit of using
// secure_delete.
- ignore_result(Execute("PRAGMA journal_mode = TRUNCATE"));
+ ignore_result(Execute("PRAGMA journal_mode=TRUNCATE"));
const base::TimeDelta kBusyTimeout =
base::TimeDelta::FromSeconds(kBusyTimeoutSeconds);
@@ -1728,7 +1735,7 @@
// 64-bit platforms.
size_t mmap_size = mmap_disabled_ ? 0 : GetAppropriateMmapSize();
std::string mmap_sql =
- base::StringPrintf("PRAGMA mmap_size = %" PRIuS, mmap_size);
+ base::StringPrintf("PRAGMA mmap_size=%" PRIuS, mmap_size);
ignore_result(Execute(mmap_sql.c_str()));
// Determine if memory-mapping has actually been enabled. The Execute() above
@@ -1889,7 +1896,7 @@
// allows SQLite to process through certain cases of corruption.
// Failing to set this pragma probably means that the database is
// beyond recovery.
- static const char kWritableSchemaSql[] = "PRAGMA writable_schema = ON";
+ static const char kWritableSchemaSql[] = "PRAGMA writable_schema=ON";
if (!Execute(kWritableSchemaSql))
return false;
@@ -1909,7 +1916,7 @@
}
// Best effort to put things back as they were before.
- static const char kNoWritableSchemaSql[] = "PRAGMA writable_schema = OFF";
+ static const char kNoWritableSchemaSql[] = "PRAGMA writable_schema=OFF";
ignore_result(Execute(kNoWritableSchemaSql));
return ret;
