diff --git a/lib/dbhash.js b/lib/dbhash.js
new file mode 100644
index 000000000..53e1aa9a8
--- /dev/null
+++ b/lib/dbhash.js
@@ -0,0 +1,11 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const hash_inputs_1 = require("./hash-inputs");
+const logging_1 = require("./logging");
+const languages_1 = require("./languages");
+const dbPath = "...";
+const logger = logging_1.getRunnerLogger(true);
+/* TODO: Do we need to unboundle here or before? */
+const stableHash = hash_inputs_1.DatabaseHash(languages_1.Language.javascript, dbPath, logger);
+logger.info(`stableHash: ${stableHash}`);
+//# sourceMappingURL=dbhash.js.map
\ No newline at end of file
diff --git a/lib/dbhash.js.map b/lib/dbhash.js.map
new file mode 100644
index 000000000..071445d70
--- /dev/null
+++ b/lib/dbhash.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"dbhash.js","sourceRoot":"","sources":["../src/dbhash.ts"],"names":[],"mappings":";;AAAA,+CAA2C;AAC3C,uCAA0C;AAC1C,2CAAqC;AAErC,MAAM,MAAM,GAAG,KAAK,CAAC;AACrB,MAAM,MAAM,GAAG,yBAAe,CAAC,IAAI,CAAC,CAAC;AAErC,mDAAmD;AACnD,MAAM,UAAU,GAAG,0BAAY,CAC3B,oBAAQ,CAAC,UAAU,EACnB,MAAM,EACN,MAAM,CACT,CAAC;AAEF,MAAM,CAAC,IAAI,CAAC,eAAe,UAAU,EAAE,CAAC,CAAC"}
\ No newline at end of file
diff --git a/lib/dbhash_cli.js b/lib/dbhash_cli.js
new file mode 100644
index 000000000..91528c02f
--- /dev/null
+++ b/lib/dbhash_cli.js
@@ -0,0 +1,11 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const hash_inputs_1 = require("./hash-inputs");
+const logging_1 = require("./logging");
+const languages_1 = require("./languages");
+const dbPath = process.argv[2];
+const logger = logging_1.getRunnerLogger(true);
+/* TODO: Do we need to unboundle here or before? */
+const stableHash = hash_inputs_1.DatabaseHash(languages_1.Language.javascript, dbPath, logger);
+logger.info(`stableHash: ${stableHash}`);
+//# sourceMappingURL=dbhash_cli.js.map
\ No newline at end of file
diff --git a/lib/dbhash_cli.js.map b/lib/dbhash_cli.js.map
new file mode 100644
index 000000000..54a303418
--- /dev/null
+++ b/lib/dbhash_cli.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"dbhash_cli.js","sourceRoot":"","sources":["../src/dbhash_cli.ts"],"names":[],"mappings":";;AAAA,+CAA2C;AAC3C,uCAA0C;AAC1C,2CAAqC;AAErC,MAAM,MAAM,GAAG,OAAO,CAAC,IAAI,CAAC,CAAC,CAAC,CAAC;AAC/B,MAAM,MAAM,GAAG,yBAAe,CAAC,IAAI,CAAC,CAAC;AAErC,mDAAmD;AACnD,MAAM,UAAU,GAAG,0BAAY,CAC3B,oBAAQ,CAAC,UAAU,EACnB,MAAM,EACN,MAAM,CACT,CAAC;AAEF,MAAM,CAAC,IAAI,CAAC,eAAe,UAAU,EAAE,CAAC,CAAC"}
\ No newline at end of file
diff --git a/lib/hash-inputs.js b/lib/hash-inputs.js
new file mode 100644
index 000000000..b35c4e4e5
--- /dev/null
+++ b/lib/hash-inputs.js
@@ -0,0 +1,63 @@
+"use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.DatabaseHash = void 0;
+const fs = __importStar(require("fs"));
+const path = __importStar(require("path"));
+const crypto = __importStar(require("crypto"));
+const languages_1 = require("./languages");
+async function DatabaseHash(language, dbPath, logger) {
+    let relDir = path.join(dbPath, `db-${language}`, "default");
+    let combined_all = crypto.createHash("sha256");
+    let combined_noExtractionTime = crypto.createHash("sha256");
+    let files = {};
+    let relFiles = fs
+        .readdirSync(relDir)
+        .filter((n) => n.endsWith(".rel"))
+        .map((n) => path.join(relDir, n));
+    if (relFiles.length === 0) {
+        throw new Error(`No '.rel' files found in ${relDir}. Has the 'create-database' action been called?`);
+    }
+    for (const relFile of relFiles) {
+        let content = fs.readFileSync(relFile); // XXX this ought to be chunked for large tables!
+        let solo = crypto.createHash("sha256");
+        solo.update(content);
+        files[path.relative(dbPath, relFile)] = solo.digest("hex");
+        if (language === languages_1.Language.javascript &&
+            path.basename(relFile) !== "extraction_time.rel") {
+            combined_noExtractionTime.update(content);
+        }
+        combined_all.update(content);
+    }
+    let stableHash = combined_noExtractionTime.digest("hex");
+    logger.info("database-hash:");
+    logger.info(JSON.stringify({
+        language,
+        combined: {
+            all: combined_all.digest("hex"),
+            noExtractionTime: stableHash,
+            files,
+        },
+    }, null, 2));
+    return stableHash;
+}
+exports.DatabaseHash = DatabaseHash;
+//# sourceMappingURL=hash-inputs.js.map
\ No newline at end of file
diff --git a/lib/hash-inputs.js.map b/lib/hash-inputs.js.map
new file mode 100644
index 000000000..e3b701904
--- /dev/null
+++ b/lib/hash-inputs.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"hash-inputs.js","sourceRoot":"","sources":["../src/hash-inputs.ts"],"names":[],"mappings":";;;;;;;;;;;;;;;;;;;;;;AAAA,uCAAyB;AACzB,2CAA6B;AAC7B,+CAAiC;AAEjC,2CAAuC;AAGhC,KAAK,UAAU,YAAY,CAC9B,QAAkB,EAChB,MAAc,EACd,MAAc;IAEhB,IAAI,MAAM,GAAG,IAAI,CAAC,IAAI,CAAC,MAAM,EAAE,MAAM,QAAQ,EAAE,EAAE,SAAS,CAAC,CAAC;IAC5D,IAAI,YAAY,GAAG,MAAM,CAAC,UAAU,CAAC,QAAQ,CAAC,CAAC;IAC/C,IAAI,yBAAyB,GAAG,MAAM,CAAC,UAAU,CAAC,QAAQ,CAAC,CAAC;IAC5D,IAAI,KAAK,GAEL,EAAE,CAAC;IACP,IAAI,QAAQ,GAAG,EAAE;SACd,WAAW,CAAC,MAAM,CAAC;SACnB,MAAM,CAAC,CAAC,CAAC,EAAE,EAAE,CAAC,CAAC,CAAC,QAAQ,CAAC,MAAM,CAAC,CAAC;SACjC,GAAG,CAAC,CAAC,CAAC,EAAE,EAAE,CAAC,IAAI,CAAC,IAAI,CAAC,MAAM,EAAE,CAAC,CAAC,CAAC,CAAC;IACpC,IAAI,QAAQ,CAAC,MAAM,KAAK,CAAC,EAAE;QACzB,MAAM,IAAI,KAAK,CACb,4BAA4B,MAAM,iDAAiD,CACpF,CAAC;KACH;IACD,KAAK,MAAM,OAAO,IAAI,QAAQ,EAAE;QAC9B,IAAI,OAAO,GAAG,EAAE,CAAC,YAAY,CAAC,OAAO,CAAC,CAAC,CAAC,iDAAiD;QACzF,IAAI,IAAI,GAAG,MAAM,CAAC,UAAU,CAAC,QAAQ,CAAC,CAAC;QACvC,IAAI,CAAC,MAAM,CAAC,OAAO,CAAC,CAAC;QACrB,KAAK,CAAC,IAAI,CAAC,QAAQ,CAAC,MAAM,EAAE,OAAO,CAAC,CAAC,GAAG,IAAI,CAAC,MAAM,CAAC,KAAK,CAAC,CAAC;QAC3D,IACE,QAAQ,KAAK,oBAAQ,CAAC,UAAU;YAChC,IAAI,CAAC,QAAQ,CAAC,OAAO,CAAC,KAAK,qBAAqB,EAChD;YACA,yBAAyB,CAAC,MAAM,CAAC,OAAO,CAAC,CAAC;SAC3C;QACD,YAAY,CAAC,MAAM,CAAC,OAAO,CAAC,CAAC;KAC9B;IACD,IAAI,UAAU,GAAG,yBAAyB,CAAC,MAAM,CAAC,KAAK,CAAC,CAAC;IACzD,MAAM,CAAC,IAAI,CAAC,gBAAgB,CAAC,CAAC;IAC9B,MAAM,CAAC,IAAI,CACT,IAAI,CAAC,SAAS,CACZ;QACE,QAAQ;QACR,QAAQ,EAAE;YACR,GAAG,EAAE,YAAY,CAAC,MAAM,CAAC,KAAK,CAAC;YAC/B,gBAAgB,EAAE,UAAU;YAC5B,KAAK;SACN;KACF,EACD,IAAI,EACJ,CAAC,CACF,CACF,CAAC;IACF,OAAO,UAAU,CAAC;AACpB,CAAC;AAlDH,oCAkDG"}
\ No newline at end of file
diff --git a/src/hash-inputs.ts b/src/hash-inputs.ts
new file mode 100644
index 000000000..27d7f1308
--- /dev/null
+++ b/src/hash-inputs.ts
@@ -0,0 +1,58 @@
+import * as fs from "fs";
+import * as path from "path";
+import * as crypto from "crypto";
+
+import { Language } from "./languages";
+import { Logger } from "./logging";
+
+export async function DatabaseHash(
+    language: Language,
+      dbPath: string,
+      logger: Logger
+    ): Promise<string> {
+    let relDir = path.join(dbPath, `db-${language}`, "default");
+    let combined_all = crypto.createHash("sha256");
+    let combined_noExtractionTime = crypto.createHash("sha256");
+    let files: {
+      [name: string]: string;
+    } = {};
+    let relFiles = fs
+      .readdirSync(relDir)
+      .filter((n) => n.endsWith(".rel"))
+      .map((n) => path.join(relDir, n));
+    if (relFiles.length === 0) {
+      throw new Error(
+        `No '.rel' files found in ${relDir}. Has the 'create-database' action been called?`
+      );
+    }
+    for (const relFile of relFiles) {
+      let content = fs.readFileSync(relFile); // XXX this ought to be chunked for large tables!
+      let solo = crypto.createHash("sha256");
+      solo.update(content);
+      files[path.relative(dbPath, relFile)] = solo.digest("hex");
+      if (
+        language === Language.javascript &&
+        path.basename(relFile) !== "extraction_time.rel"
+      ) {
+        combined_noExtractionTime.update(content);
+      }
+      combined_all.update(content);
+    }
+    let stableHash = combined_noExtractionTime.digest("hex");
+    logger.info("database-hash:");
+    logger.info(
+      JSON.stringify(
+        {
+          language,
+          combined: {
+            all: combined_all.digest("hex"),
+            noExtractionTime: stableHash,
+            files,
+          },
+        },
+        null,
+        2
+      )
+    );
+    return stableHash;
+  }
\ No newline at end of file