{ "schemaVersion": 1, "evidenceType": "measured-synthetic-workload", "generatedAt": "2026-10-14T08:20:23.161354+00:00", "scriptSha256": "6e5021017ce56a3042e6834cd9bf9b92858f079aa9b6533f11ab47063ed0d1a3", "environment": { "sqlite": "3.45.1", "sqliteSourceId": "2024-01-30 16:01:20 e876e51a0ed5c5b3126f52e532044363a014bc594cfefa87ffb5b82257ccalt1", "sqliteCompileOptions": [ "ATOMIC_INTRINSICS=1", "COMPILER=gcc-13.3.0", "DEFAULT_AUTOVACUUM", "DEFAULT_CACHE_SIZE=-2000", "DEFAULT_FILE_FORMAT=4", "DEFAULT_JOURNAL_SIZE_LIMIT=-1", "DEFAULT_MMAP_SIZE=0", "DEFAULT_PAGE_SIZE=4096", "DEFAULT_PCACHE_INITSZ=20", "DEFAULT_RECURSIVE_TRIGGERS", "DEFAULT_SECTOR_SIZE=4096", "DEFAULT_SYNCHRONOUS=2", "DEFAULT_WAL_AUTOCHECKPOINT=1000", "DEFAULT_WAL_SYNCHRONOUS=2", "DEFAULT_WORKER_THREADS=0", "DIRECT_OVERFLOW_READ", "ENABLE_COLUMN_METADATA", "ENABLE_DBSTAT_VTAB", "ENABLE_FTS3", "ENABLE_FTS3_PARENTHESIS", "ENABLE_FTS3_TOKENIZER", "ENABLE_FTS4", "ENABLE_FTS5", "ENABLE_LOAD_EXTENSION", "ENABLE_MATH_FUNCTIONS", "ENABLE_PREUPDATE_HOOK", "ENABLE_RTREE", "ENABLE_SESSION", "ENABLE_STMTVTAB", "ENABLE_UNLOCK_NOTIFY", "ENABLE_UPDATE_DELETE_LIMIT", "HAVE_ISNAN", "LIKE_DOESNT_MATCH_BLOBS", "MALLOC_SOFT_LIMIT=1024", "MAX_ATTACHED=10", "MAX_COLUMN=2000", "MAX_COMPOUND_SELECT=500", "MAX_DEFAULT_PAGE_SIZE=32768", "MAX_EXPR_DEPTH=1000", "MAX_FUNCTION_ARG=127", "MAX_LENGTH=1000000000", "MAX_LIKE_PATTERN_LENGTH=50000", "MAX_MMAP_SIZE=0x7fff0000", "MAX_PAGE_COUNT=0xfffffffe", "MAX_PAGE_SIZE=65536", "MAX_SCHEMA_RETRY=25", "MAX_SQL_LENGTH=1000000000", "MAX_TRIGGER_DEPTH=1000", "MAX_VARIABLE_NUMBER=250000", "MAX_VDBE_OP=250000000", "MAX_WORKER_THREADS=8", "MUTEX_PTHREADS", "SECURE_DELETE", "SOUNDEX", "SYSTEM_MALLOC", "TEMP_STORE=1", "THREADSAFE=1", "USE_URI" ], "python": "3.12.3", "os": "Linux", "kernel": "6.8.0-146-generic", "statfsLabel": "ext2/ext3" }, "workload": { "rows": 32, "payloadBytes": 1024, "updateBatches": 4, "initialWalGeneration": 1, "lastGeneration": 5, "randomness": "none" }, "caseCount": 2, "cases": [ { "case": "pinned-read-transaction", "settings": { "page_size": 4096, "synchronous": 2, "wal_autocheckpoint": 0, "busy_timeout": 0, "journal_mode": "wal" }, "readerPinnedInitially": true, "observations": [ { "label": "after-generation-2", "mode": "PASSIVE", "busy": 0, "logFrames": 22, "checkpointedFrames": 11, "walBytes": 90672, "walExists": true, "writerOracle": { "generation": 2, "rowCount": 32, "allRowsMatchOracle": true }, "readerOracle": { "generation": 1, "rowCount": 32, "allRowsMatchOracle": true } }, { "label": "after-generation-3", "mode": "PASSIVE", "busy": 0, "logFrames": 33, "checkpointedFrames": 11, "walBytes": 135992, "walExists": true, "writerOracle": { "generation": 3, "rowCount": 32, "allRowsMatchOracle": true }, "readerOracle": { "generation": 1, "rowCount": 32, "allRowsMatchOracle": true } }, { "label": "after-generation-4", "mode": "PASSIVE", "busy": 0, "logFrames": 44, "checkpointedFrames": 11, "walBytes": 181312, "walExists": true, "writerOracle": { "generation": 4, "rowCount": 32, "allRowsMatchOracle": true }, "readerOracle": { "generation": 1, "rowCount": 32, "allRowsMatchOracle": true } }, { "label": "after-generation-5", "mode": "PASSIVE", "busy": 0, "logFrames": 55, "checkpointedFrames": 11, "walBytes": 226632, "walExists": true, "writerOracle": { "generation": 5, "rowCount": 32, "allRowsMatchOracle": true }, "readerOracle": { "generation": 1, "rowCount": 32, "allRowsMatchOracle": true } } ], "truncateBeforeRelease": { "label": "before-reader-release", "mode": "TRUNCATE", "busy": 1, "logFrames": 55, "checkpointedFrames": 11, "walBytes": 226632, "walExists": true }, "restartAfterRelease": { "label": "after-reader-release", "mode": "RESTART", "busy": 0, "logFrames": 55, "checkpointedFrames": 55, "walBytes": 226632, "walExists": true }, "truncateAfterRestart": { "label": "after-restart", "mode": "TRUNCATE", "busy": 0, "logFrames": 0, "checkpointedFrames": 0, "walBytes": 0, "walExists": true }, "readerConnectionStillOpen": true, "finalOracle": { "generation": 5, "rowCount": 32, "allRowsMatchOracle": true }, "integrityCheck": "ok" }, { "case": "idle-open-connection", "settings": { "page_size": 4096, "synchronous": 2, "wal_autocheckpoint": 0, "busy_timeout": 0, "journal_mode": "wal" }, "readerPinnedInitially": false, "observations": [ { "label": "after-generation-2", "mode": "PASSIVE", "busy": 0, "logFrames": 22, "checkpointedFrames": 22, "walBytes": 90672, "walExists": true, "writerOracle": { "generation": 2, "rowCount": 32, "allRowsMatchOracle": true }, "readerOracle": { "generation": 2, "rowCount": 32, "allRowsMatchOracle": true } }, { "label": "after-generation-3", "mode": "PASSIVE", "busy": 0, "logFrames": 11, "checkpointedFrames": 11, "walBytes": 90672, "walExists": true, "writerOracle": { "generation": 3, "rowCount": 32, "allRowsMatchOracle": true }, "readerOracle": { "generation": 3, "rowCount": 32, "allRowsMatchOracle": true } }, { "label": "after-generation-4", "mode": "PASSIVE", "busy": 0, "logFrames": 11, "checkpointedFrames": 11, "walBytes": 90672, "walExists": true, "writerOracle": { "generation": 4, "rowCount": 32, "allRowsMatchOracle": true }, "readerOracle": { "generation": 4, "rowCount": 32, "allRowsMatchOracle": true } }, { "label": "after-generation-5", "mode": "PASSIVE", "busy": 0, "logFrames": 11, "checkpointedFrames": 11, "walBytes": 90672, "walExists": true, "writerOracle": { "generation": 5, "rowCount": 32, "allRowsMatchOracle": true }, "readerOracle": { "generation": 5, "rowCount": 32, "allRowsMatchOracle": true } } ], "truncateBeforeRelease": { "label": "before-reader-release", "mode": "TRUNCATE", "busy": 0, "logFrames": 0, "checkpointedFrames": 0, "walBytes": 0, "walExists": true }, "restartAfterRelease": { "label": "after-reader-release", "mode": "RESTART", "busy": 0, "logFrames": 0, "checkpointedFrames": 0, "walBytes": 0, "walExists": true }, "truncateAfterRestart": { "label": "after-restart", "mode": "TRUNCATE", "busy": 0, "logFrames": 0, "checkpointedFrames": 0, "walBytes": 0, "walExists": true }, "readerConnectionStillOpen": true, "finalOracle": { "generation": 5, "rowCount": 32, "allRowsMatchOracle": true }, "integrityCheck": "ok" } ], "limits": [ "One deterministic schedule on synthetic data, not a throughput benchmark or field sample.", "All SQLite calls run sequentially on one thread; read transactions overlap writes in lifetime only.", "No process crash, power loss, I/O fault, multi-writer race or backup procedure is tested.", "Exact frame counts and file sizes are observations of the recorded build, not universal constants.", "The installed SQLite version is recorded, not endorsed as patched or safe for production.", "PASSIVE checkpoint calls perform work; they are not passive telemetry reads." ], "sources": [ "https://www.sqlite.org/wal.html", "https://www.sqlite.org/c3ref/wal_checkpoint_v2.html", "https://www.sqlite.org/pragma.html#pragma_wal_checkpoint", "https://www.sqlite.org/isolation.html" ] }