X-Git-Url: http://git.vrable.net/?p=cumulus.git;a=blobdiff_plain;f=localdb.cc;h=ca8355951bedd9f102c957208cec5e472d79424c;hp=8a5e1f1382b5c8c0e44eb10a3ca11a53e284f561;hb=3d780590edec4583eb3ef0ca16120afd0f7451f9;hpb=893aa36d4dee18cc85843c441219c8e177282e79 diff --git a/localdb.cc b/localdb.cc index 8a5e1f1..ca83559 100644 --- a/localdb.cc +++ b/localdb.cc @@ -1,7 +1,23 @@ -/* LBS: An LFS-inspired filesystem backup system - * Copyright (C) 2007 Michael Vrable +/* Cumulus: Efficient Filesystem Backup to the Cloud + * Copyright (C) 2007-2008 The Cumulus Developers + * See the AUTHORS file for a list of contributors. * - * When creating backup snapshots, maintain a local database of data blocks and + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/* When creating backup snapshots, maintain a local database of data blocks and * checksums, in addition to the data contents (which may be stored remotely). * This database is consulted when attempting to build incremental snapshots, * as it says which objects can be reused. @@ -15,13 +31,21 @@ #include #include +#include #include #include "localdb.h" #include "store.h" +#include "util.h" +using std::max; +using std::min; +using std::set; using std::string; +static const int SCHEMA_MAJOR = 0; +static const int SCHEMA_MINOR = 11; + /* Helper function to prepare a statement for execution in the current * database. */ sqlite3_stmt *LocalDb::Prepare(const char *sql) @@ -32,7 +56,8 @@ sqlite3_stmt *LocalDb::Prepare(const char *sql) rc = sqlite3_prepare_v2(db, sql, strlen(sql), &stmt, &tail); if (rc != SQLITE_OK) { - throw IOException(string("Error preparing statement: ") + sql); + ReportError(rc); + fatal(string("Error preparing statement: ") + sql); } return stmt; @@ -45,7 +70,7 @@ void LocalDb::ReportError(int rc) } void LocalDb::Open(const char *path, const char *snapshot_name, - const char *snapshot_scheme) + const char *snapshot_scheme, double intent) { int rc; @@ -53,36 +78,56 @@ void LocalDb::Open(const char *path, const char *snapshot_name, if (rc) { fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db)); sqlite3_close(db); - throw IOException("Error opening local database"); + fatal("Error opening local database"); } rc = sqlite3_exec(db, "begin", NULL, NULL, NULL); if (rc) { fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db)); sqlite3_close(db); - throw IOException("Error starting transaction"); + fatal("Error starting transaction"); } sqlite3_extended_result_codes(db, 1); + /* Check that the local database format is the correct version; if not, + * report an error. */ + sqlite3_stmt *stmt = Prepare("select major, minor from schema_version"); + + rc = sqlite3_step(stmt); + if (rc != SQLITE_ROW) { + fatal("Unable to read local database version from database"); + } else if (rc == SQLITE_ROW) { + int major = sqlite3_column_int(stmt, 0); + int minor = sqlite3_column_int(stmt, 1); + if (major != SCHEMA_MAJOR || minor != SCHEMA_MINOR) { + fprintf(stderr, + "Local database does not have required schema version!\n" + " expected: %d.%d, found: %d.%d\n", + SCHEMA_MAJOR, SCHEMA_MINOR, major, minor); + fatal("Unable to continue."); + } + } + sqlite3_finalize(stmt); + + if (snapshot_scheme == NULL) + snapshot_scheme = ""; + /* Insert this snapshot into the database, and determine the integer key * which will be used to identify it. */ - sqlite3_stmt *stmt = Prepare("insert into " - "snapshots(name, scheme, timestamp) " - "values (?, ?, julianday('now'))"); + stmt = Prepare("insert into snapshots(name, scheme, timestamp, intent) " + "values (?, ?, julianday('now'), ?)"); sqlite3_bind_text(stmt, 1, snapshot_name, strlen(snapshot_name), SQLITE_TRANSIENT); - if (snapshot_scheme == NULL) - sqlite3_bind_null(stmt, 2); - else - sqlite3_bind_text(stmt, 2, snapshot_scheme, strlen(snapshot_scheme), - SQLITE_TRANSIENT); + sqlite3_bind_text(stmt, 2, snapshot_scheme, strlen(snapshot_scheme), + SQLITE_TRANSIENT); + sqlite3_bind_double(stmt, 3, intent); rc = sqlite3_step(stmt); if (rc != SQLITE_DONE) { ReportError(rc); sqlite3_close(db); - throw IOException("Database execution error!"); + fatal("Database execution error!"); } snapshotid = sqlite3_last_insert_rowid(db); @@ -90,13 +135,54 @@ void LocalDb::Open(const char *path, const char *snapshot_name, if (snapshotid == 0) { ReportError(rc); sqlite3_close(db); - throw IOException("Find snapshot id"); + fatal("Find snapshot id"); + } + + /* Create a temporary table which will be used to keep track of the objects + * used by this snapshot. When the database is closed, we will summarize + * the results of this table into segments_used. */ + rc = sqlite3_exec(db, + "create temporary table snapshot_refs (" + " segmentid integer not null," + " object text not null," + " size integer not null" + ")", NULL, NULL, NULL); + if (rc != SQLITE_OK) { + ReportError(rc); + sqlite3_close(db); + fatal("Database initialization"); + } + rc = sqlite3_exec(db, + "create unique index snapshot_refs_index " + "on snapshot_refs(segmentid, object)", + NULL, NULL, NULL); + if (rc != SQLITE_OK) { + ReportError(rc); + sqlite3_close(db); + fatal("Database initialization"); } } void LocalDb::Close() { int rc; + + /* Summarize the snapshot_refs table into segment_utilization. */ + sqlite3_stmt *stmt = Prepare( + "insert or replace into segment_utilization " + "select ? as snapshotid, segmentid, sum(size) " + "from snapshot_refs group by segmentid" + ); + sqlite3_bind_int64(stmt, 1, snapshotid); + rc = sqlite3_step(stmt); + if (rc != SQLITE_OK && rc != SQLITE_DONE) { + ReportError(rc); + sqlite3_close(db); + fprintf(stderr, "DATABASE ERROR: Unable to create segment summary!\n"); + } + sqlite3_finalize(stmt); + + /* Commit changes to the database and close. */ rc = sqlite3_exec(db, "commit", NULL, NULL, NULL); if (rc != SQLITE_OK) { fprintf(stderr, "DATABASE ERROR: Can't commit database!\n"); @@ -116,7 +202,7 @@ int64_t LocalDb::SegmentToId(const string &segment) SQLITE_TRANSIENT); rc = sqlite3_step(stmt); if (rc != SQLITE_DONE) { - throw IOException("Could not execute INSERT statement!"); + fatal("Could not execute INSERT statement!"); } sqlite3_finalize(stmt); @@ -126,11 +212,11 @@ int64_t LocalDb::SegmentToId(const string &segment) rc = sqlite3_step(stmt); if (rc == SQLITE_DONE) { - throw IOException("No segment found by id"); + fatal("No segment found by id"); } else if (rc == SQLITE_ROW) { result = sqlite3_column_int64(stmt, 0); } else { - throw IOException("Error executing find segment by id query"); + fatal("Error executing find segment by id query"); } sqlite3_finalize(stmt); @@ -149,11 +235,11 @@ string LocalDb::IdToSegment(int64_t segmentid) rc = sqlite3_step(stmt); if (rc == SQLITE_DONE) { - throw IOException("No segment found by id"); + fatal("No segment found by id"); } else if (rc == SQLITE_ROW) { result = (const char *)sqlite3_column_text(stmt, 0); } else { - throw IOException("Error executing find segment by id query"); + fatal("Error executing find segment by id query"); } sqlite3_finalize(stmt); @@ -161,13 +247,16 @@ string LocalDb::IdToSegment(int64_t segmentid) return result; } -void LocalDb::StoreObject(const ObjectReference& ref, - const string &checksum, int64_t size, - double age) +void LocalDb::StoreObject(const ObjectReference& ref, double age) { int rc; sqlite3_stmt *stmt; + assert(ref.has_checksum()); + string checksum = ref.get_checksum(); + assert(ref.range_is_exact()); + int64_t size = ref.get_range_length(); + if (age == 0.0) { stmt = Prepare("insert into block_index(" "segmentid, object, checksum, size, timestamp) " @@ -194,6 +283,17 @@ void LocalDb::StoreObject(const ObjectReference& ref, } sqlite3_finalize(stmt); + + if (age != 0.0) { + stmt = Prepare("update segments " + "set mtime = coalesce(max(mtime, ?), ?) " + "where segmentid = ?"); + sqlite3_bind_double(stmt, 1, age); + sqlite3_bind_double(stmt, 2, age); + sqlite3_bind_int64(stmt, 3, SegmentToId(ref.get_segment())); + rc = sqlite3_step(stmt); + sqlite3_finalize(stmt); + } } ObjectReference LocalDb::FindObject(const string &checksum, int64_t size) @@ -213,6 +313,7 @@ ObjectReference LocalDb::FindObject(const string &checksum, int64_t size) } else if (rc == SQLITE_ROW) { ref = ObjectReference(IdToSegment(sqlite3_column_int64(stmt, 0)), (const char *)sqlite3_column_text(stmt, 1)); + ref.set_range(0, size, true); } else { fprintf(stderr, "Could not execute SELECT statement!\n"); ReportError(rc); @@ -223,14 +324,15 @@ ObjectReference LocalDb::FindObject(const string &checksum, int64_t size) return ref; } -bool LocalDb::IsOldObject(const string &checksum, int64_t size, double *age) +bool LocalDb::IsOldObject(const string &checksum, int64_t size, double *age, + int *group) { int rc; sqlite3_stmt *stmt; bool found = false; - stmt = Prepare("select segmentid, object, timestamp from block_index " - "where checksum = ? and size = ?"); + stmt = Prepare("select segmentid, object, timestamp, expired " + "from block_index where checksum = ? and size = ?"); sqlite3_bind_text(stmt, 1, checksum.c_str(), checksum.size(), SQLITE_TRANSIENT); sqlite3_bind_int64(stmt, 2, size); @@ -241,6 +343,7 @@ bool LocalDb::IsOldObject(const string &checksum, int64_t size, double *age) } else if (rc == SQLITE_ROW) { found = true; *age = sqlite3_column_double(stmt, 2); + *group = sqlite3_column_int(stmt, 3); } else { fprintf(stderr, "Could not execute SELECT statement!\n"); ReportError(rc); @@ -258,6 +361,11 @@ bool LocalDb::IsAvailable(const ObjectReference &ref) sqlite3_stmt *stmt; bool found = false; + // Special objects (such as the zero object) aren't stored in segments, and + // so are always available. + if (!ref.is_normal()) + return true; + stmt = Prepare("select count(*) from block_index " "where segmentid = ? and object = ? and expired is null"); sqlite3_bind_int64(stmt, 1, SegmentToId(ref.get_segment())); @@ -280,42 +388,132 @@ bool LocalDb::IsAvailable(const ObjectReference &ref) return found; } +set LocalDb::GetUsedSegments() +{ + int rc; + sqlite3_stmt *stmt; + set result; + + stmt = Prepare("select segment from segments " + "where segmentid in (select segmentid from snapshot_refs)"); + + while (true) { + rc = sqlite3_step(stmt); + if (rc == SQLITE_ROW) { + const char *segment + = reinterpret_cast(sqlite3_column_text(stmt, 0)); + result.insert(segment); + } else if (rc == SQLITE_DONE) { + break; + } else { + ReportError(rc); + } + } + + sqlite3_finalize(stmt); + + return result; +} + void LocalDb::UseObject(const ObjectReference& ref) { int rc; sqlite3_stmt *stmt; - stmt = Prepare("insert or ignore into snapshot_contents " - "select blockid, ? as snapshotid from block_index " + if (!ref.is_normal()) + return; + + int64_t old_size = 0; + stmt = Prepare("select size from snapshot_refs " "where segmentid = ? and object = ?"); - sqlite3_bind_int64(stmt, 1, snapshotid); - sqlite3_bind_int64(stmt, 2, SegmentToId(ref.get_segment())); + sqlite3_bind_int64(stmt, 1, SegmentToId(ref.get_segment())); string obj = ref.get_sequence(); - sqlite3_bind_text(stmt, 3, obj.c_str(), obj.size(), SQLITE_TRANSIENT); - + sqlite3_bind_text(stmt, 2, obj.c_str(), obj.size(), SQLITE_TRANSIENT); rc = sqlite3_step(stmt); - if (rc != SQLITE_DONE) { - fprintf(stderr, "Could not execute INSERT statement!\n"); - ReportError(rc); + if (rc == SQLITE_ROW) { + old_size = sqlite3_column_int64(stmt, 0); } - sqlite3_finalize(stmt); + + // Attempt to determine the underlying size of the object. This may + // require a database lookup if the length is not encoded into the object + // reference already. + int64_t object_size = 0; + if (ref.range_is_exact()) { + object_size = ref.get_range_length(); + } else { + stmt = Prepare("select size from block_index " + "where segmentid = ? and object = ?"); + sqlite3_bind_int64(stmt, 1, SegmentToId(ref.get_segment())); + obj = ref.get_sequence(); + sqlite3_bind_text(stmt, 2, obj.c_str(), obj.size(), SQLITE_TRANSIENT); + rc = sqlite3_step(stmt); + if (rc == SQLITE_ROW) { + object_size = sqlite3_column_int64(stmt, 0); + } else { + fprintf(stderr, "Warning: No block found in block_index for %s\n", + ref.to_string().c_str()); + } + sqlite3_finalize(stmt); + } + + // Possibly mark additional bytes as being referenced. The number of bytes + // referenced can only be increased (up to the object size). The bytes + // referenced will be set to the object size only if the entire object is + // referenced at once: a series of partial ranges that add up to the total + // size will have a reference size capped at just less than the full object + // size (we can't tell if some bytes were referenced multiple times, and + // thus we conservatively assume some bytes might still be unreferenced). + int64_t new_refs = old_size; + if (ref.has_range()) { + new_refs = ref.get_range_length(); + } else { + new_refs = object_size; + } + int64_t new_size = old_size + new_refs; + if (old_size < object_size && new_refs < object_size) + new_size = min(new_size, object_size - 1); + new_size = min(object_size, new_size); + new_size = max(new_size, (int64_t)0); + + if (new_size != old_size) { + stmt = Prepare("insert or replace " + "into snapshot_refs(segmentid, object, size) " + "values (?, ?, ?)"); + sqlite3_bind_int64(stmt, 1, SegmentToId(ref.get_segment())); + obj = ref.get_sequence(); + sqlite3_bind_text(stmt, 2, obj.c_str(), obj.size(), SQLITE_TRANSIENT); + sqlite3_bind_int64(stmt, 3, new_size); + + rc = sqlite3_step(stmt); + if (rc != SQLITE_DONE) { + fprintf(stderr, "Could not execute INSERT statement!\n"); + ReportError(rc); + } + + sqlite3_finalize(stmt); + } } void LocalDb::SetSegmentChecksum(const std::string &segment, const std::string &path, - const std::string &checksum) + const std::string &checksum, + int data_size, int disk_size) { int rc; sqlite3_stmt *stmt; - stmt = Prepare("update segments set path = ?, checksum = ? " + stmt = Prepare("update segments set path = ?, checksum = ?, " + "data_size = ?, disk_size = ?, " + "mtime = coalesce(mtime, julianday('now')) " "where segmentid = ?"); sqlite3_bind_text(stmt, 1, path.c_str(), path.size(), SQLITE_TRANSIENT); sqlite3_bind_text(stmt, 2, checksum.c_str(), checksum.size(), SQLITE_TRANSIENT); - sqlite3_bind_int64(stmt, 3, SegmentToId(segment)); + sqlite3_bind_int64(stmt, 3, data_size); + sqlite3_bind_int64(stmt, 4, disk_size); + sqlite3_bind_int64(stmt, 5, SegmentToId(segment)); rc = sqlite3_step(stmt); if (rc != SQLITE_DONE) { @@ -325,3 +523,128 @@ void LocalDb::SetSegmentChecksum(const std::string &segment, sqlite3_finalize(stmt); } + +bool LocalDb::GetSegmentChecksum(const string &segment, + string *seg_path, + string *seg_checksum) +{ + int rc; + sqlite3_stmt *stmt; + ObjectReference ref; + int found = false; + + stmt = Prepare("select path, checksum from segments where segment = ?"); + sqlite3_bind_text(stmt, 1, segment.c_str(), segment.size(), + SQLITE_TRANSIENT); + + rc = sqlite3_step(stmt); + if (rc == SQLITE_DONE) { + } else if (rc == SQLITE_ROW) { + found = true; + const char *val; + + val = (const char *)sqlite3_column_text(stmt, 0); + if (val == NULL) + found = false; + else + *seg_path = val; + + val = (const char *)sqlite3_column_text(stmt, 1); + if (val == NULL) + found = false; + else + *seg_checksum = val; + } else { + fprintf(stderr, "Could not execute SELECT statement!\n"); + ReportError(rc); + } + + sqlite3_finalize(stmt); + + return found; +} + +/* Look up and return the packed representation of the subblock chunk + * signatures. Returns true if signatures were found for the specified object, + * and if so sets *buf to point at a buffer of memory (allocated with malloc; + * the caller should free it), and *len to the length of the buffer. */ +bool LocalDb::LoadChunkSignatures(ObjectReference ref, + void **buf, size_t *len, + string *algorithm) +{ + int rc; + sqlite3_stmt *stmt; + int found = false; + + stmt = Prepare("select signatures, algorithm from subblock_signatures " + "where blockid = (select blockid from block_index " + " where segmentid = ? and object = ?)"); + sqlite3_bind_int64(stmt, 1, SegmentToId(ref.get_segment())); + string obj = ref.get_sequence(); + sqlite3_bind_text(stmt, 2, obj.c_str(), obj.size(), SQLITE_TRANSIENT); + + rc = sqlite3_step(stmt); + if (rc == SQLITE_DONE) { + } else if (rc == SQLITE_ROW) { + const void *data = sqlite3_column_blob(stmt, 0); + *len = sqlite3_column_bytes(stmt, 0); + + if (*len > 0) { + *buf = malloc(*len); + if (*buf != NULL) { + memcpy(*buf, data, *len); + *algorithm = (const char *)sqlite3_column_text(stmt, 1); + found = true; + } + } + } else { + fprintf(stderr, "Could not execute SELECT statement!\n"); + ReportError(rc); + } + + sqlite3_finalize(stmt); + + return found; +} + +/* Store the subblock chunk signatures for a specified object. The object + * itself must have already been indexed in the database. */ +void LocalDb::StoreChunkSignatures(ObjectReference ref, + const void *buf, size_t len, + const string& algorithm) +{ + int rc; + sqlite3_stmt *stmt; + + stmt = Prepare("select blockid from block_index " + "where segmentid = ? and object = ?"); + sqlite3_bind_int64(stmt, 1, SegmentToId(ref.get_segment())); + string obj = ref.get_sequence(); + sqlite3_bind_text(stmt, 2, obj.c_str(), obj.size(), SQLITE_TRANSIENT); + + rc = sqlite3_step(stmt); + if (rc != SQLITE_ROW) { + fprintf(stderr, + "Could not determine blockid in StoreChunkSignatures!\n"); + ReportError(rc); + fatal("Error getting blockid"); + } + int64_t blockid = sqlite3_column_int64(stmt, 0); + sqlite3_finalize(stmt); + + stmt = Prepare("insert or replace " + "into subblock_signatures(blockid, algorithm, signatures) " + "values (?, ?, ?)"); + sqlite3_bind_int64(stmt, 1, blockid); + sqlite3_bind_text(stmt, 2, algorithm.c_str(), algorithm.size(), + SQLITE_TRANSIENT); + sqlite3_bind_blob(stmt, 3, buf, len, SQLITE_TRANSIENT); + + rc = sqlite3_step(stmt); + if (rc != SQLITE_DONE) { + fprintf(stderr, "Could not insert sub-block checksums!\n"); + ReportError(rc); + } + + sqlite3_finalize(stmt); +}