X-Git-Url: http://git.vrable.net/?p=cumulus.git;a=blobdiff_plain;f=localdb.cc;h=7304d49ba4c70aae53b69d5f9a092c1a969588a9;hp=c58549bc6dbef8a100644294db1ffe02a4c03764;hb=f38dd9bcb0caffd3fc9126b05788c936690e8288;hpb=fb51ed45b5b584dc7223ecce4f2703f48a2dea17 diff --git a/localdb.cc b/localdb.cc index c58549b..7304d49 100644 --- a/localdb.cc +++ b/localdb.cc @@ -1,7 +1,24 @@ -/* LBS: An LFS-inspired filesystem backup system - * Copyright (C) 2007 Michael Vrable +/* Cumulus: Smart Filesystem Backup to Dumb Servers * - * When creating backup snapshots, maintain a local database of data blocks and + * Copyright (C) 2007-2008 The Regents of the University of California + * Written by Michael Vrable + * + * 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. @@ -15,14 +32,41 @@ #include #include +#include #include #include "localdb.h" #include "store.h" +#include "util.h" +using std::min; using std::string; -void LocalDb::Open(const char *path, const char *snapshot_name) +/* Helper function to prepare a statement for execution in the current + * database. */ +sqlite3_stmt *LocalDb::Prepare(const char *sql) +{ + sqlite3_stmt *stmt; + int rc; + const char *tail; + + rc = sqlite3_prepare_v2(db, sql, strlen(sql), &stmt, &tail); + if (rc != SQLITE_OK) { + ReportError(rc); + fatal(string("Error preparing statement: ") + sql); + } + + return stmt; +} + +void LocalDb::ReportError(int rc) +{ + fprintf(stderr, "Result code: %d\n", rc); + fprintf(stderr, "Error message: %s\n", sqlite3_errmsg(db)); +} + +void LocalDb::Open(const char *path, const char *snapshot_name, + const char *snapshot_scheme, double intent) { int rc; @@ -30,53 +74,105 @@ 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"); } - /* Insert this snapshot into the database, and determine the integer key - * which will be used to identify it. */ - sqlite3_stmt *stmt; - static const char s[] = - "insert into snapshots(name, timestamp) " - "values (?, julianday('now'))"; - const char *tail; + sqlite3_extended_result_codes(db, 1); - rc = sqlite3_prepare_v2(db, s, strlen(s), &stmt, &tail); - if (rc != SQLITE_OK) { - sqlite3_close(db); - throw IOException("Error adding snapshot"); - } + 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, intent) " + "values (?, ?, julianday('now'), ?)"); sqlite3_bind_text(stmt, 1, snapshot_name, strlen(snapshot_name), 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); sqlite3_finalize(stmt); 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 segments_used. */ + sqlite3_stmt *stmt = Prepare( + "insert or replace into segments_used " + "select ? as snapshotid, segmentid, max(utilization) from (" + " select segmentid, cast(used as real) / size as utilization " + " from " + " (select segmentid, sum(size) as used from snapshot_refs " + " group by segmentid) " + " join segments using (segmentid) " + " union " + " select segmentid, utilization from segments_used " + " where snapshotid = ? " + ") group by segmentid" + ); + sqlite3_bind_int64(stmt, 1, snapshotid); + sqlite3_bind_int64(stmt, 2, 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, "Can't commit database!\n"); + fprintf(stderr, "DATABASE ERROR: Can't commit database!\n"); + ReportError(rc); } sqlite3_close(db); } @@ -85,40 +181,28 @@ int64_t LocalDb::SegmentToId(const string &segment) { int rc; sqlite3_stmt *stmt; - static const char s1[] = - "insert or ignore into segments(segment) values (?);"; - static const char s2[] = - "select segmentid from segments where segment = ?"; - const char *tail; int64_t result; - rc = sqlite3_prepare_v2(db, s1, strlen(s1), &stmt, &tail); - if (rc != SQLITE_OK) { - throw IOException("Find id by segment name"); - } + stmt = Prepare("insert or ignore into segments(segment) values (?)"); sqlite3_bind_text(stmt, 1, segment.c_str(), segment.size(), 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); - rc = sqlite3_prepare_v2(db, s2, strlen(s2), &stmt, &tail); - if (rc != SQLITE_OK) { - throw IOException("Find id by segment name"); - } - + stmt = Prepare("select segmentid from segments where segment = ?"); sqlite3_bind_text(stmt, 1, segment.c_str(), segment.size(), SQLITE_TRANSIENT); 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); @@ -130,25 +214,18 @@ string LocalDb::IdToSegment(int64_t segmentid) { int rc; sqlite3_stmt *stmt; - static const char s[] = - "select segment from segments where segmentid = ?"; - const char *tail; string result; - rc = sqlite3_prepare_v2(db, s, strlen(s), &stmt, &tail); - if (rc != SQLITE_OK) { - throw IOException("Find segment by id"); - } - + stmt = Prepare("select segment from segments where segmentid = ?"); sqlite3_bind_int64(stmt, 1, 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); @@ -157,19 +234,20 @@ string LocalDb::IdToSegment(int64_t segmentid) } void LocalDb::StoreObject(const ObjectReference& ref, - const string &checksum, int64_t size) + const string &checksum, int64_t size, + double age) { int rc; sqlite3_stmt *stmt; - static const char s[] = - "insert into " - "block_index(segmentid, object, checksum, size, timestamp) " - "values (?, ?, ?, ?, julianday('now'))"; - const char *tail; - rc = sqlite3_prepare_v2(db, s, strlen(s), &stmt, &tail); - if (rc != SQLITE_OK) { - return; + if (age == 0.0) { + stmt = Prepare("insert into block_index(" + "segmentid, object, checksum, size, timestamp) " + "values (?, ?, ?, ?, julianday('now'))"); + } else { + stmt = Prepare("insert into block_index(" + "segmentid, object, checksum, size, timestamp) " + "values (?, ?, ?, ?, ?)"); } sqlite3_bind_int64(stmt, 1, SegmentToId(ref.get_segment())); @@ -178,31 +256,37 @@ void LocalDb::StoreObject(const ObjectReference& ref, sqlite3_bind_text(stmt, 3, checksum.c_str(), checksum.size(), SQLITE_TRANSIENT); sqlite3_bind_int64(stmt, 4, size); + if (age != 0.0) + sqlite3_bind_double(stmt, 5, age); rc = sqlite3_step(stmt); if (rc != SQLITE_DONE) { fprintf(stderr, "Could not execute INSERT statement!\n"); + ReportError(rc); } 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) { int rc; sqlite3_stmt *stmt; - static const char s[] = - "select segmentid, object from block_index " - "where checksum = ? and size = ? and expired is null"; - const char *tail; - ObjectReference ref; - rc = sqlite3_prepare_v2(db, s, strlen(s), &stmt, &tail); - if (rc != SQLITE_OK) { - return ref; - } - + stmt = Prepare("select segmentid, object from block_index " + "where checksum = ? and size = ? and expired is null"); sqlite3_bind_text(stmt, 1, checksum.c_str(), checksum.size(), SQLITE_TRANSIENT); sqlite3_bind_int64(stmt, 2, size); @@ -212,8 +296,10 @@ 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); } sqlite3_finalize(stmt); @@ -221,29 +307,303 @@ ObjectReference LocalDb::FindObject(const string &checksum, int64_t size) return ref; } +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, 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); + + rc = sqlite3_step(stmt); + if (rc == SQLITE_DONE) { + found = false; + } 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); + } + + sqlite3_finalize(stmt); + + return found; +} + +/* Does this object still exist in the database (and not expired)? */ +bool LocalDb::IsAvailable(const ObjectReference &ref) +{ + int rc; + 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())); + sqlite3_bind_text(stmt, 2, ref.get_sequence().c_str(), + ref.get_sequence().size(), SQLITE_TRANSIENT); + + rc = sqlite3_step(stmt); + if (rc == SQLITE_DONE) { + found = false; + } else if (rc == SQLITE_ROW) { + if (sqlite3_column_int(stmt, 0) > 0) + found = true; + } else { + fprintf(stderr, "Could not execute SELECT statement!\n"); + ReportError(rc); + } + + sqlite3_finalize(stmt); + + return found; +} + void LocalDb::UseObject(const ObjectReference& ref) { int rc; sqlite3_stmt *stmt; - static const char s[] = - "insert or ignore into snapshot_contents " - "select blockid, ? as snapshotid from block_index " - "where segmentid = ? and object = ?"; - const char *tail; - rc = sqlite3_prepare_v2(db, s, strlen(s), &stmt, &tail); - if (rc != SQLITE_OK) { + 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, 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) { + old_size = sqlite3_column_int64(stmt, 0); } + sqlite3_finalize(stmt); + + int64_t block_size = 0; + 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) { + block_size = sqlite3_column_int64(stmt, 0); + } else { + string refstr = ref.to_string(); + fprintf(stderr, "No block found in block_index for %s\n", + refstr.c_str()); + sqlite3_finalize(stmt); + return; + } + sqlite3_finalize(stmt); + + int64_t new_size = old_size; + if (ref.has_range()) { + new_size += ref.get_range_length(); + new_size = min(new_size, block_size); + } else { + new_size = block_size; + } + + 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::UseSegment(const std::string &segment, double utilization) +{ + int rc; + sqlite3_stmt *stmt; + stmt = Prepare("insert or replace " + "into segments_used(snapshotid, segmentid, utilization) " + "values (?, ?, ?)"); sqlite3_bind_int64(stmt, 1, snapshotid); - sqlite3_bind_int64(stmt, 2, SegmentToId(ref.get_segment())); + sqlite3_bind_int64(stmt, 2, SegmentToId(segment)); + sqlite3_bind_double(stmt, 3, utilization); + + rc = sqlite3_step(stmt); + if (rc != SQLITE_DONE) { + fprintf(stderr, "Could not insert segment use record!\n"); + ReportError(rc); + } + + sqlite3_finalize(stmt); +} + +void LocalDb::SetSegmentChecksum(const std::string &segment, + const std::string &path, + const std::string &checksum, + int size) +{ + int rc; + sqlite3_stmt *stmt; + + stmt = Prepare("update segments set path = ?, checksum = ?, 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, size); + sqlite3_bind_int64(stmt, 4, SegmentToId(segment)); + + rc = sqlite3_step(stmt); + if (rc != SQLITE_DONE) { + fprintf(stderr, "Could not update segment checksum in database!\n"); + ReportError(rc); + } + + 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, 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) { + } 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 execute INSERT statement!\n"); + fprintf(stderr, "Could not insert sub-block checksums!\n"); + ReportError(rc); } sqlite3_finalize(stmt);