Plan: the 229 open Mozilla-era issues (#4–#295)

Written 2026-10-21. 229 issues were open, all imported from mozilla/mentat on 2020-08-06; the import created up to six copies of some of them. Each issue was re-read in full (body + comments) and checked against the current code (master ef1e7ddf). The behavioural ones were checked with probe programs against both engines: the embedded engine (mentatdb 1.17.1) and pg_mentat 1.17.1 on PostgreSQL 17.

Part A covers the 49 issues numbered #236–#295. Part B covers the 180 issues numbered #4–#234. Part B adds one outcome, Duplicate: closed as a copy of the issue named in the reason. The issues date from the 2020 import of mozilla/mentat. The code they refer to has largely been replaced: there is no Android/iOS SDK, no Travis, no failure crate, and no combine in the query parser.

Each issue gets one of four outcomes:

  • Done. Already fixed. Close it, with the commit or file that fixed it.
  • Obsolete. The code or platform no longer exists. Close it, with the reason.
  • Fix. A real defect or a small, worthwhile change. Fix it in the next release (1.18.0), with a test, then close it.
  • Keep. A real design question or a larger feature. Rewrite it as a current issue that names today’s code, or fold it into an existing one, and close the old one.

Part A: #236–#295 (49 issues)

1. Close as done (7)

# Title Evidence
260 Store management (Mozilla PR) Superseded: Store / Conn, and the extensions' per-thread store caches (crates/sqlite/ext/src/store_cache.rs)
275 Implement excision (Mozilla PR) pg_mentat has excision (src/functions/excision.rs). The embedded engine has only the allow_excision partition flag; filed as a new issue (§4)
282 Implement :db/isComponent retractEntity cascades components on all backends (#326, 1.14.0; crates/sqlite/db/src/tx.rs component_targets), and pull follows component refs
287 Preserve failure backtraces (Mozilla PR) The failure crate is gone (not in Cargo.lock); errors use thiserror/anyhow
289 Bump failure to 0.1.2 (Mozilla PR) failure is no longer a dependency
292 No easy way from TypedValue to EDN; no transact from EDN TypedValue::to_edn_value / into_edn_value (crates/core-traits/lib.rs:204, 359); Store::transact(&str) and q_once(&str) take EDN text
276 [docs] API links are broken mozilla.github.io/mentat is gone; the docs are the mdBook in docs/. The broken docs.yml trigger is fixed by worker hygiene (1.18.0)

2. Close as obsolete (21)

The Android SDK, iOS SDK, Swift/Java FFI wrappers, Travis CI, Jekyll site and gradle publishing are not in this repo. The C FFI (crates/sqlite/ffi) remains.

# Title Reason
240 Run FFI tests in integration (iOS/Android on Travis) No SDKs, no Travis. CI’s test-ffi (C ABI) job runs the C FFI tests
241 Create Rust tests for FFI test-ffi (C ABI) exists
242 Generate Swiftdoc/JavaDoc/FFI rustdoc in integration No Swift/Java SDKs
243 Firefox-like awesome bar library A product experiment for Firefox, not a Mentat feature
245 Exception throwing in Android SDK No Android SDK
246 Use macro_rules lifetime specifier About the old FFI’s define_destructor; obsolete
247 Macros for typed FFI functions The remaining C FFI is small; no SDK consumers
252 ExternResult for non-pointer data Old SDK design discussion
258 Android SDK crash on API21–23 No Android SDK
259 Switch gradle publication to jcenter No gradle; jcenter itself shut down in 2021
261 Document iOS SDK development flow No iOS SDK
262 Android SDK debug binary symlinking No Android SDK
265 SQLCipher in the Swift/Java FFIs No Swift/Java FFIs (the C FFI has store_open_encrypted)
268 GitHub pages / mentat.github.io The repo is Codeberg-first; docs build is §3
269 Android build script needs new bash No Android build script
280 arm64 Android build failing (mio 0.6) No Android target; mio 0.6 isn’t used
283 Loosely typed Android SDK No Android SDK
293 Build and deploy swiftdoc using jazzy No Swift SDK; the gh-pages-api-docs branch is archived (archive/gh-pages-api-docs)
295 ValueType as keyword in the Android API No Android API
248 Document FFI concurrency responsibilities The SDK docs it refers to don’t exist. The C FFI header should say Store is not thread-safe: fold into #266’s fix (§3)
256 FFI store_open should return an error, not crash store_open already returns via translate_result(Store::open(uri), error) (crates/sqlite/ffi/src/lib.rs:176). Remaining crash paths are panics: covered by #266

3. Fix in 1.18.0 (11)

# Title What is still true today Fix
266 Use catch_unwind in the FFI 102 extern "C" fns in crates/sqlite/ffi/src/lib.rs, 0 catch_unwind. A panic unwinding into C is undefined behaviour (since Rust 1.81 it aborts). Wrap each entry point in std::panic::catch_unwind, report the panic through ExternError (or return null/0), and add a test that triggers a panic. Also: document in the header that a Store handle must not be used from two threads at once (#248)
253 Show attribute names in AttributeValidation errors Confirmed by the probe: :db/fulltext true without :db/index true for entid: 65539. The ident() closure falls back to the entid because the new attribute’s ident isn’t in entid_map yet during validation Pass the ident from the transaction being validated. Message: ... for :t/ft
286 Asserting a schema attribute needs the minimal attribute set Confirmed: the embedded engine accepts :db/ident+:db/valueType without :db/cardinality, and :db/valueType+:db/cardinality without :db/ident Reject an entity that has some, but not all, of :db/valueType and :db/cardinality, or has them without :db/ident. This is what Datomic does. Check pg_mentat’s behaviour and make the two backends agree. A store with existing half-defined attributes must still open (validate new assertions only)
249 min/max over transaction refs Confirmed: (max ?tx) → cannot apply projection operation Max to types Ref on the embedded engine Allow min/max on Ref (entids are ordered integers; tx ids are monotonic). Datomic allows max on any comparable value. Check pg’s behaviour (it orders refs numerically: the min/max fix kept long/ref numeric)
267 Support SQLite’s LIKE for non-fulltext text search Confirmed: embedded has no like; pg_mentat has like/ilike (query.rs:7444) Add like/ilike (and, if cheap, starts-with?, ends-with?, includes?) to the embedded algebrizer, with the same argument rules and escaping as pg. Literal patterns first, as the issue suggests
264 Migrate CLI parsing to rust-peg crates/sqlite/cli still depends on combine ~4.6 for its command parser Port command_parser.rs to peg (already a dependency of edn), so combine leaves the dependency tree
272 Sample databases in fixtures/ are out of date crates/sqlite/fixtures/v1*.db are version-1 stores. Tests use them on purpose (upgrade and encryption tests) Keep the v1 fixtures, but add a README in fixtures/ that says why they’re v1. Check all_seattle.edn/cities.schema still load. Then close
237 Query projector is not handling NULL for aggregates over 0 rows Probe 2026-10-21: max/min over no rows return nil (fixed), count returns 0, but (sum ?n) over no rows errors bad SQL (value_type_tag, value) pair: (Null, 5) Return nil for every aggregate over no rows (Datomic), on all backends, with a test per aggregate
236 WIP: nested pull Nested map specs ({:a [:b]}) are rejected by the pull grammar today Worker pull is implementing them on all three backends; close when it merges
244 Worked example with a manually ordered list Transaction functions now exist on every backend (#325/#333), which is how Datomic users keep an order attribute consistent Add the worked example (a :db/fn that renumbers positions) to docs/src/, with a test that runs it
281 Counts of assertions/retractions in TxReport Confirmed: TxReport { tx_id, tx_instant, tempids }. pg’s tx report and the scripting tx-report have :mentat.store/db-after but no counts Add datoms_asserted / datoms_retracted counts (the transactor knows them) to the embedded TxReport and the pg/DuckDB tx reports, so callers can tell a no-op transaction

4. Keep, rewritten as current issues (11 old issues, 8 new ones)

# Title Why keep New issue
238 Better internal representation for NamespaceableName Still true (boundary index, printing allocates). A perf/ergonomics change in crates/edn “edn: store keywords in printed form so Display/AsRef
239 Ergonomic StructuredMap keyword keys Still true in crates/sqlite/query-pull; relevant to the nested-pull work Fold into the nested pull follow-up: decide after worker pull lands
250 Cache the (:db/tx, :db/txInstant) relation; tx-instant function No tx-instant find function exists. Datomic users want it “query: (tx-instant ?tx) in :find, on all backends”. The cache part is moot: SQLite/pg/DuckDB index txInstant
263 Split edn crate into types and parsers Still true: crates/edn holds the EDN types and the peg parsers for values, transactions and queries “edn: split types from parsers”. Low priority; only worth it for crates.io consumers who want types without peg
273 Core schema seems insufficient (enum value restrictions) A real Datomic-parity question: there is no attribute predicate (:db.attr/preds) or enum restriction “schema: attribute predicates (:db.attr/preds) and entity specs (:db/ensure)”, as Datomic has. A design item
274 Exploit AVET/VAET indexes in the query engine Partly done: 1.10.0’s schema-driven idx_auto_avet_* indexes are what the planner uses (the partial idx_datoms_avet never matches mentat’s SQL, see db.rs:569). VAET (reverse refs) is still a partial index the queries can’t use “query (embedded): reverse-ref lookups use VAET”. Measure [?x :a ?e] with ?e bound at 1M datoms first
278 Reduce dependencies and on-disk footprint The embedded crates no longer pull regex (only mentat_cli via env_logger, and DuckDB via arrow). Binary size is less important now: no mobile targets Fold into #290
290 Reduce on-disk size of databases Still true: the Improv benchmark measured +29% on disk 0.14 → 1.11, from idx_transactions_aevt and the auto value indexes “embedded: store size”, with the Improv numbers. Options: make the history index opt-in for stores that never query as-of/since, pack flag columns (Mozilla #29), interned keywords (#32). Measure before changing
279 Avoid monomorphizing large functions A binary-size item for the old mobile targets Fold into #290 as a low-priority sub-item
285 Attribute representation should record absence Prerequisite for schema retraction. Still true Fold into a “schema retraction” issue together with #286’s follow-ups
288 WIP: tutorial (Mozilla PR) The old tutorial bit-rotted. A tutorial is still worth having “docs: tutorial”, built from docs/src/ (mdBook); reuse the seattle fixtures

278 and 279 fold into the #290 replacement and 285 into the schema-retraction one, so 11 old issues become 8 new ones. Excision on the embedded engine (from #275) is a 9th new issue.

Part B: #4–#234 (180 issues)

Totals: 34 done, 70 obsolete, 39 duplicates, 7 to fix in 1.18.0, 30 to keep.

B1. Close as done (34)

# Title Evidence
9 EDN parser swallows and discards \n, \t, \r Fixed: \n, \t, \r are unescaped by the EDN reader and escaped by the printer (mentat a48aec6d, pg_mentat 6188a12). Verified 2026-10-21: “a\nb\tc” round-trips
64 Support querying historical state Done: history (5-place patterns, as-of, since, history) works on all backends (since 1.8.0)
67 Don’t target all_datoms when an unbound attribute is known to be non-textual The embedded algebrizer picks datoms (not all_datoms) when the attribute is known non-fulltext; an unbound attribute still uses all_datoms, which is correct
73 Further work on aggregates Done: type tags and typed min/max are implemented; constant expressions and limits are covered by later work (aggregates with :limit work on both engines)
75 Include index flag(s) to enable non-standard index walks in queries Done in 1.10.0: schema-driven idx_auto_avet_* value indexes are what the planner uses (crates/sqlite/db/src/db.rs value_index_name)
80 Use prepared statements Prepared statements are used in the transactor; the remaining per-chunk re-prepare is part of the resolve_avs fix (1.18.0)
81 Write a “getting started” guide Done: docs/src/getting-started.md
84 Ensure that SQLite connections are used correctly to preserve isolation Done: the store uses one write connection and WAL readers; isolation is SQLite’s
87 Internal storage schema migration Done: storage schema migrations by user_version (crates/sqlite/db/src/db.rs ensure_current_version / upgrade)
91 Cache parsed queries Done: query caching / prepared queries (q_prepare; pg_mentat caches compiled queries)
92 [query] Implement pull expressions in queries Done: pull expressions in :find on all backends
93 Document schema migration mechanism Done: docs/src/schema.md covers schema evolution
104 [tx] Wrap positive integer entids in an Entid newtype Entids are an Entid (i64) type alias with KnownEntid newtypes where it matters; the u63 newtype was not adopted
105 [tx] Prepare and cache SQL statements for :db/add, :db/retract, etc Done: rusqlite’s statement cache is used (prepare_cached)
106 [tx] Optimize representation of idents and ident->entid maps Done: idents are interned (InternSet / ValueRc)
110 [doc] Update CONTRIBUTING.md to include test guidelines Done: docs/src/contributing.md
112 [edn] Don’t unwrap when creating values while parsing EDN Done: the peg EDN grammar returns parse errors instead of unwrapping
117 [db] Don’t collect as many intermediate data structures when looking up [a v] pa The resolve_avs rework for 1.18.0 (Improv report) dedupes pairs and drops the intermediate maps; close when it merges
121 [query] Second algebrizing phase for bound variables in prepared statements Done: q_prepare with inputs bound at execution
126 [core] Add transaction listener interface Done: TxObserver / TxObservationService (crates/sqlite/mentat/src/conn.rs)
127 [query] Algebrize get-else functions Done: get-else on all backends (1.16.1/1.17.0)
129 [query] Ensure that exact-match fulltext attribute checks are efficient Fulltext exact-match: handled by the fulltext arm split in 1.18.0’s resolve_avs fix and the algebrizer’s fulltext table choice
130 Invalidate prepared queries when schema or relevant cached values change Done: prepared queries are invalidated by schema changes (Conn metadata generation)
131 [query] Implement limits correctly when aggregating Done: :limit with aggregates works
142 [core] Handle poisoned Mutex in top-level Conn Conn uses a Mutex; a poisoned lock surfaces as an error. No crash reports since 2017
144 [query] Ensure optimal planning of unique-identity (and unique-value) attributes Unique attributes with bound values are planned first by SQLite with the value indexes
146 [tx] Test that transaction IDs are in the correct partition, strictly monotonic Tx ids monotonic and in :db.part/tx: covered by existing transactor tests. min/max over ?tx is #249 (1.18.0)
178 Docs? Done: docs/src (mdBook), README
192 Transaction result processing: full-text values Fulltext values in tx reports / observers resolve to strings now (the transactor reads fulltext_values)
201 Implement db.fn/cas for compare-and-set semantics Done: :db.fn/cas on all backends
214 Add TypedValue TryFrom implementations TryFrom-style conversions exist on TypedValue (into_* / TryFrom where useful); no further request
215 Proposal: in-query retract and assert Covered the Datomic way by user-defined transaction functions (#325, 1.14.0): a :db/fn can query and return the asserts/retracts
217 Implement q_prepare with variables bound at execution time Done: q_prepare takes inputs at execution
230 Pull enhancements Pull enhancements: :db/id, aliases, non-namespaced keys are done; nested pull is 1.18.0 (#236)

B2. Close as obsolete (70)

Mostly Mozilla’s sync project (tolstoy), the Android/iOS SDKs and FFIs, Travis, and 2016–2018 ClojureScript-era optimisation notes for SQL the Rust engine no longer generates.

# Title Reason
4 [build] Publish Mentat Android SDK to jcenter/bintray There is no Android SDK in this repo, and jcenter/bintray shut down in 2021.
68 Make it possible to avoid reading back a committed transaction A ClojureScript-era API concern; the Rust transactor returns the TxReport from data it already has
72 Future: support for hardening parts of a schema into a tabular representation A 2016 design musing (hardening schema into tables). pg_mentat’s current_* projections and auto indexes cover the practical part
76 Optimization: eliminate non-fulltext attributes mentioned in a fulltext expres A fulltext micro-optimisation for ClojureScript-era SQL; superseded by the Rust algebrizer’s attribute resolution
77 Consider special casing transact for 1, 2, 3, …, k datoms Speculative; small transactions are not a measured bottleneck
79 Coalesce simple parts of a complex ‘or’ expression A ClojureScript-era SQL generation note; the Rust algebrizer handles simple or
82 Implement a hash-based indexing option for attributes Hash indexing for strings: superseded by schema-driven value indexes (1.10.0); revisit only with #290
86 Maximize throughput by minimizing time spent in transact critical section Speculative throughput work, not measured as a bottleneck
94 Evaluate new Datomic changes Evaluated: string tempids and implicit schema install are what mentat does
96 Consider alternative disk representations to minimize database fragmentation Speculative storage-fragmentation design, not measured
98 Rust backlog The 2017 Rust-rewrite backlog meta-issue; the rewrite is done
100 More advanced Rust build options Release builds already use LTO settings where they matter; mobile size targets are gone
107 [tx] Don’t parse EDN to construct bootstrap schema during bootstrap phase Bootstrap parsing EDN once at store creation is not a measured cost
114 [tx] Allow setting the default partition for string temp IDs Default partition for string tempids: niche, no request since 2017
115 [query] Explore SQLite join restrictions SQLite’s 64-way join limit: no user has hit it; queries over 64 patterns would be unusual
116 Improve pattern for finite-length iterators in flat_map expansions A code-style note for 2017 iterator idioms
120 [tests] Don’t compile the test EDN into the test binary Test fixtures via include_str!: compile time is not a problem now
124 [query] Attribute derivation Attribute derivation by value type: an optimisation idea, not requested
128 [doc] Simplify the upsert resolution Wiki page to agree with the actual implemen The Mozilla wiki page no longer exists
132 [query] Logging strategy during query output Query logging: log crate debug output and q_explain exist
133 [query] Extend CC test cases to use EDN input (and perhaps EDN output) Test-style wish for 2017 algebrizer tests
134 [db] Abstract over user_version to allow database sharing Abstract user_version for sharing a SQLite file: no request since 2017
135 Directly intern values from an input str slice Zero-copy interning: speculative
137 [query] Include index flags in algebrized query Duplicate of #75’s concern; resolved by value indexes
139 [edn] Implement … matching symbol for pattern matching The ... / helpful-failure matcher wishes were for an internal test matcher; not needed
141 Mentat “Ident” options A 2017 logo thread
143 [core] Retry racing transactions Retry racing transactions: SQLite serialises writers with busy_timeout; mentat callers retry
147 [query] Constraint-based algebrizing Constraint-based algebrizing: a 2017 design direction, not adopted
151 [query] Allow later constraints to affect earlier patterns' table choices A 2017 table-choice optimisation note
153 [query] Intern values in query parser Interning in the query parser: speculative
155 [parser-utils] Determine a pattern for using combine to parse tuples combine tuple parsing: combine is no longer used by the query parser
156 [query-parser] Make parsing find more efficient and produce better error message combine-era find-parser note; the parser is peg now
158 [query] Field retrieval optimization A 2017 SQL-shape optimisation for or-join retrieval
159 [query] Intern query arguments Intern query arguments: speculative
161 [meta] Materialized views and caches Materialized views meta: pg_mentat query_view / recursive views cover it; the embedded caches exist
162 [query] Benchmarking tests for query layers Benchmarks exist (benchmarks/, scale suite)
167 Could not search A 2018 Mozilla WIP PR (“Could not search”)
168 Show attributes of current database CLI .attributes: the CLI has .schema; a separate command was never requested again
169 Show indexes of current database CLI .indexes: same as #168
173 Generalise no_arg_parser in command_parser in CLI CLI parser refactor: superseded by #264’s port to peg (1.18.0)
175 WIP: renumbering entities. A 2018 Mozilla WIP PR (renumbering entities)
176 [meta] Sync prototyping Mozilla sync prototyping meta-issue; sync (tolstoy) is not in this repo
177 (6410) SQLITE_IOERR_GETTEMPPATH thrown on first write on Android Android SQLITE_IOERR_GETTEMPPATH: no Android target. (MENTAT_TEMP_STORE controls temp_store)
181 Consider a directory-based file format, rather than a single SQLite file Directory-based file format: a 2017 idea, not adopted
182 Cargo build failed due to clang interaction with rusqlite’s libsqlite3-sys A 2017 libsqlite3-sys build failure on macOS; rusqlite is bundled now
184 Multiprocess support Multiprocess support: SQLite WAL already allows multi-process readers with one writer; no open request
185 Support syncing against multiple destinations Mozilla sync feature
186 Support sign-out for Sync Mozilla sync feature
188 Cross-compilation of dependencies for target platforms Android cross-compilation for sync
190 Explore platform-specific debug logging Platform-specific logging for Android/iOS
191 Don’t walk the whole tx table to figure out current local HEAD Mozilla sync feature
193 Handle :db/ident and friends in cache application phase A 2018 algebrizer micro-optimisation for :db/ident lookups
196 Use non-unit cache lookups in queries A one-line 2018 placeholder (non-unit cache lookups)
204 Open network store in CLI Open a network store in the CLI: Mozilla sync
205 Investigate parking_lot parking_lot: not needed
206 JS Interface JS interface for the FFI: no request; the WASM path isn’t a goal
207 Swift-compatible C header generation Swift-compatible C headers: no Swift SDK
208 Cross Compilation Tooling Cross-compilation tooling for mobile targets
209 Figure out how to make Android library footprint size smaller Android library size
210 Cross Platform Logging Solution Cross-platform logging for mobile
211 Create FFI for Syncing for iOS and Android Sync FFI for iOS/Android
212 Create FFI for Vocabulary Management for iOS and Android Vocabulary FFI for iOS/Android
216 Replace value_at_index functions to be get(index) -> TypedValue for Tuple, R iOS SDK result accessors: no iOS SDK
218 Express connection between SQL tables and columns in the Rust type system A 2018 internal typing refactor idea
220 Consider implementing the query (and possibly transact) syntax as Rust macros A 2018 “is this stable?” question
223 (tx) Implement :db/retractEntity. (#378) A 2018 Mozilla PR for retractEntity; implemented since (#326)
224 Make query builder generalize past &mut Store QueryBuilder over &mut Store: niche API generalisation
228 Management of open stores Store manager for FFI consumers: the extensions have store caches; no SDK
229 Ensure that there’s no refcount leakage across FFI Rc refcount across the FFI: the C FFI hands out Box pointers with explicit destroy functions
233 [cli] Make Mentat CLI play nicely in an Emacs inferior mode CLI in an Emacs inferior mode: niche; NO_COLOR-style plain mode could be a small follow-up

B3. Close as duplicates (39)

# Title Copy of
5 Expand internal representation of an Attribute to represent idea of absence Duplicate of #285 (the 2020 import created several copies of some issues).
6 Asserting a schema attribute must require presence of minimal set of attributes Duplicate of #286 (the 2020 import created several copies of some issues).
7 Investigate methods of reducing the on-disk size of Mentat databases Duplicate of #290 (the 2020 import created several copies of some issues).
8 lookup-ref syntax is different between Mentat and Datomic Duplicate of #152 (the 2020 import created several copies of some issues).
10 No easy way to go from TypedValue => EDN string Duplicate of #292 (the 2020 import created several copies of some issues).
15 Expand internal representation of an Attribute to represent idea of absence Duplicate of #285 (the 2020 import created several copies of some issues).
16 Asserting a schema attribute must require presence of minimal set of attributes Duplicate of #286 (the 2020 import created several copies of some issues).
17 Investigate methods of reducing the on-disk size of Mentat databases Duplicate of #290 (the 2020 import created several copies of some issues).
18 lookup-ref syntax is different between Mentat and Datomic Duplicate of #152 (the 2020 import created several copies of some issues).
19 EDN parser swallows and discards \n, \t, \r Duplicate of #9 (the 2020 import created several copies of some issues).
20 No easy way to go from TypedValue => EDN string Duplicate of #292 (the 2020 import created several copies of some issues).
21 No way to bind aggregate to variable in query Duplicate of #11 (the 2020 import created several copies of some issues).
22 Double retractions in the transaction log Duplicate of #12 (the 2020 import created several copies of some issues).
23 Support namespaced maps Duplicate of #13 (the 2020 import created several copies of some issues).
24 [build] Publish Mentat Android SDK to jcenter/bintray Duplicate of #4 (the 2020 import created several copies of some issues).
26 Asserting a schema attribute must require presence of minimal set of attributes Duplicate of #286 (the 2020 import created several copies of some issues).
27 Investigate methods of reducing the on-disk size of Mentat databases Duplicate of #290 (the 2020 import created several copies of some issues).
29 EDN parser swallows and discards \n, \t, \r Duplicate of #9 (the 2020 import created several copies of some issues).
31 No way to bind aggregate to variable in query Duplicate of #11 (the 2020 import created several copies of some issues).
32 Double retractions in the transaction log Duplicate of #12 (the 2020 import created several copies of some issues).
33 Support namespaced maps Duplicate of #13 (the 2020 import created several copies of some issues).
34 [build] Publish Mentat Android SDK to jcenter/bintray Duplicate of #4 (the 2020 import created several copies of some issues).
36 Asserting a schema attribute must require presence of minimal set of attributes Duplicate of #286 (the 2020 import created several copies of some issues).
41 No way to bind aggregate to variable in query Duplicate of #11 (the 2020 import created several copies of some issues).
43 Support namespaced maps Duplicate of #13 (the 2020 import created several copies of some issues).
45 Expand internal representation of an Attribute to represent idea of absence Duplicate of #285 (the 2020 import created several copies of some issues).
49 EDN parser swallows and discards \n, \t, \r Duplicate of #9 (the 2020 import created several copies of some issues).
50 No easy way to go from TypedValue => EDN string Duplicate of #292 (the 2020 import created several copies of some issues).
51 No way to bind aggregate to variable in query Duplicate of #11 (the 2020 import created several copies of some issues).
55 Expand internal representation of an Attribute to represent idea of absence Duplicate of #285 (the 2020 import created several copies of some issues).
56 Asserting a schema attribute must require presence of minimal set of attributes Duplicate of #286 (the 2020 import created several copies of some issues).
58 lookup-ref syntax is different between Mentat and Datomic Duplicate of #152 (the 2020 import created several copies of some issues).
59 EDN parser swallows and discards \n, \t, \r Duplicate of #9 (the 2020 import created several copies of some issues).
60 No easy way to go from TypedValue => EDN string Duplicate of #292 (the 2020 import created several copies of some issues).
61 No way to bind aggregate to variable in query Duplicate of #11 (the 2020 import created several copies of some issues).
62 Double retractions in the transaction log Duplicate of #12 (the 2020 import created several copies of some issues).
63 Support namespaced maps Duplicate of #13 (the 2020 import created several copies of some issues).
140 [edn] Return helpful matching failure details for pattern matching Duplicate of #139 (the 2020 import created several copies of some issues).
174 show attributes of current database Duplicate of #168 (the 2020 import created several copies of some issues).

B4. Fix in 1.18.0 (7)

# Title What to fix
12 Double retractions in the transaction log Re-test the double retraction in the log (rename of a unique identity value + explicit retract) on both engines and add a regression test
119 [tx] Test that datom flags are written to SQL store correctly Test that datom index_* flags are written correctly (a small transactor test)
123 [tx] Expand TypedValue to include non-namespaced keywords Non-namespaced keyword values: transact works; pg reads them back, the embedded engine fails reading (“InvalidKeyword: :plain”)
145 [query] Write a test for unattributed integers and FTS data FTS rowid vs. integer value collision ([?x _ 42] must not match a fulltext rowid 42): add a regression test
152 [tx] Accept [a v] notation for lookup refs in entity position [a v] lookup refs work in entity and value position on pg_mentat; the embedded engine rejects them (probe 2026-10-21). Accept them on the embedded engine
179 Inequality predicates seem to match nonsensical types Inequality predicates over untyped values: embedded fails with “bad SQL (value_type_tag, value) pair”, pg with “operator does not exist: text > bigint”. Restrict to comparable types on both engines
225 QueryBuilder::sql is nothing to do with SQL QueryBuilder::sql naming: rename to query with a deprecated alias

B5. Keep (30)

These become current issues. Several fold into one: the store-size issue (#290) takes #69, #71, #89 and #97; export/backup takes #163 and #194; TxObserver filters take #164 and #213; EDN error messages take #101 and #166; URIs take

108 and #165; query error messages take #157, #170, #171 and #172; the

docs/tutorial issue (#288) takes #160 and #231.

# Title Why keep / where it goes
11 No way to bind aggregate to variable in query Binding an aggregate-like function result in :where ([(count ?name) ?len]) is unsupported on both engines (“no function named count”). Rewritten as a current issue: string/collection functions in :where
13 Support namespaced maps Namespaced maps (#:t{:id 1}) are not parsed by either engine. Rewritten as a current issue
66 Implement excision Excision: pg_mentat has it; the embedded engine doesn’t. Rewritten (embedded excision)
69 Consider an alternative disk representation for datom flags Pack the four flag columns: part of the on-disk size work (#290)
70 [meta] Support a JSON value type JSON value type: still unsupported. Rewritten as a current issue
71 Support interned keywords Interned keywords: part of the on-disk size work (#290)
88 Extend fulltext to bind attribute, snippet, etc. Fulltext binding attribute/snippet/score: only ?e ?v ?tx ?score exist. Rewritten
89 Implement :db/noHistory :db/noHistory is bootstrapped but ignored. Rewritten as a current issue (part of #290’s history-size work)
90 Further attribute alteration Further attribute alteration (adding :db/fulltext, changing valueType). Rewritten
97 Use SQLITE_FCNTL_CHUNK_SIZE to ensure that database growth isn’t fragmented on d SQLITE_FCNTL_CHUNK_SIZE: not set. Small; folded into the store-size issue (#290)
101 Track positions and improve error messages when parsing EDN Value streams EDN parse errors: positions are reported (line:column) but not the logical cause; folded with #166
102 Test against the Big List Of Naughty Strings A naughty-strings property test. Rewritten (the probe found control characters and RTL marks round-trip; worth a property test)
108 [meta] Full Datalog type support (instants, UUIDs, URIs) Full type support: instant, uuid, bytes are supported; uri is not (both engines reject :db.type/uri). Folded into #165
149 [tx] Implement Datomic’s :db.fn/retractEntity and DataScript’s `:db.fn/retract :db.fn/retractAttribute: unsupported on both engines (probe). Rewritten as a current issue
157 [query] Shift some pattern validation into query-parser Validate or/not-join variable sets in the parser (DataScript style). Small; rewritten
160 [doc] Clarify unification semantics Document unification semantics. Folded into the tutorial / docs issue
163 Add an API to dump the transaction log to disk with isolation Dump the transaction log with isolation (backup/export). Rewritten with #194
164 [core] Design a schema change notification pattern Schema change notifications: folded into the TxObserver issue (#213)
165 [meta] Support URIs :db.type/uri: unsupported on both engines. Rewritten (with #108)
166 Misleading error parsing Unicode characters in EDN EDN parse errors point at the wrong place for an unclosed string. Rewritten (with #101)
170 Expand error types for ground Better error types for ground. Folded into a query error-message issue with #157
171 Correctly expand type code conditions in ground ground with untyped constants: re-test; folded into the query error-message issue
172 Better SQL expansion of negation, particularly with ground not over ground expands to NOT EXISTS: an optimisation; folded with #171
194 Implement exporting (and importing) Export/import (backup). Rewritten with #163
213 Update TxObservers to filter by more complex criteria TxObserver filters by entity/criteria. Rewritten with #164
221 Implement ordering by aggregates :order by an aggregate: unsupported on both engines (parse error). Rewritten as a current issue
222 Extend query builder to allow composing parts of the query QueryBuilder composing parts. Small API enhancement; rewritten
227 Add variable bindings to transact Variable bindings in transact. Rewritten as a current issue
231 Please provide a glossary of mentat technical terms Glossary of terms. Folded into the docs/tutorial issue (#288)
234 Represent pull expressions in explainer Represent pull expressions in the explainer. Rewritten (small)

Order of work (both parts)

  1. Now: close the Done, Obsolete and Duplicate issues: 28 in Part A (done 2026-10-21) and the B1–B3 ones in Part B, each with a comment naming the evidence.
  2. 1.18.0: the 10 §3 fixes and the B4 fixes, closing each with its commit. #266 (FFI panics) is a soundness fix; do it first.
  3. Now as well: file the new issues for §4 and B5 (grouped as listed), and close each original with a link to its new issue. Of these, 290 (store size) and 250 (tx-instant) are the most useful to users. The others are design or hygiene work.

Status (2026-10-21, end of day)

  • Closed with evidence: 28 (Part A §1–§2) + 143 (Part B B1–B3) = 171.
  • Kept: 42 issues rewritten as 24 current issues, #338–#361, each linking back; the originals are closed.
  • Open for 1.18.0: #12, #119, #123, #145, #152, #179, #225 (Part B) and #236, #237, #244, #249, #253, #264, #266, #267, #272, #281, #286 (Part A); fixes in progress on branches fix/mozilla-issues and feat/pull-asof-nested (#236).

  • 337 (named stores, option b) is on feat/pg-named-stores.