[php-src] Issue #8928: `oci8` is leaking memory with long query/CLOB

Issue: https://github.com/php/php-src/issues/8928 Author: mvorisek ### Description The following code: ```php <?php public function testCharacterTypeFieldLong(): void { $conn = $this->db->getConnection()->getConnection()->getNativeConnection(); // var_dump(get_debug_type($conn)); // prints string(26) "resource (oci8 connection)" for ($i = 0; $i < 10; $i++) { $sql = 'select CONCAT(CONCAT(TO_CLOB(\'atk__binary__u5f8mzx4vsm8g2c9__7eedd908a7b43ba3b8ec88338437e8bce2087e297a2dc612deb10abe043100adc20e566a3dce26ca6652419d1e992245fdf793148f18f34f746047d8d41c5c704b4ef28e199215f65d714a1dd5d9756146675340cb27cf576b3cfc4498239c1fdfc7137b2c097f28e3acc30f300105b00bbfa2b93aa6b5bde985368932ede5aec10d078103aa11c5b2e17d2a792eddeba887348338e7a4b7ef8ba0bb5f7348f8d794d36f5b4cf463779017db8c1bf06d59fed19a219625fa69553e9ecdc9516542fb97249b20d0ff6c58506443c8cc9f68543f6e5a4dd295d6f95e7249f18d1ada91166276f5e682398635a9eaa1ba8aeea5b6ab10c4020680afc00ce4dc782f7c2be0b3a7b43ba3b8ec88338437e8bce2087e297a2dc612deb10abe043100adc20e566a3dce26ca6652419d1e992245fdf793148f18f34f746047d8d41c5c704b4ef28e199215f65d714a1dd5d9756146675340cb27cf576b3cfc4498239c1fdfc7137b2c097f28e3acc30f300105b00bbfa2b93aa6b5bde985368932ede5aec10d078103aa11c5b2e17d2a792eddeba887348338e7a4b7ef8ba0bb5f7348f8d794d36f5b4cf463779017db8c1bf06d59fed19a219625fa69553e9ecdc9516542fb97249b20d0ff6c58506443c8cc9f68543f6e5a4dd295d6f95e7249f18d1ada9116627\'), TO_CLOB(\'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\')), CONCAT(TO_CLOB(\'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\'), CONCAT(TO_CLOB(\'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\'), TO_CLOB(\'2fb97249b20d0ff6c58506443c8cc9f68543f6e5a4dd295d6f95e7249f18d1ada91166276f5e682398635a9eaa1ba8aeea5b6ab10c4020680afc00ce4dc782f7c2be0\')))) AS "v" from "DUAL"'; $expectedStr = 'atk__binary__u5f8mzx4vsm8g2c9__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'; $stid = oci_parse($conn, $sql); oci_execute($stid); $row = oci_fetch_array($stid, \OCI_ASSOC); $res = $row['v']->load(); $this->assertSame(strlen($expectedStr), strlen($res)); $this->assertTrue($expectedStr === $res); $prevMem = isset($mem) && $i > 4 ? $mem : null; gc_collect_cycles(); gc_collect_cycles(); $mem = memory_get_usage(); if ($prevMem !== null && $mem !== $prevMem) { throw new \Exception('leak detected'); } } } ``` Resulted in this output: ``` Exception: leak detected ``` I have verified, the leak is consistent across PHP 7.4 - master and only oci8 ext is affected. With pdo_oci, there is no leak, for exactly the same query. See https://github.com/atk4/data/runs/7199098438 For smaller query, even with CLOB, there is also no leak. ### PHP Version tested PHP 7.4, 8.0, 8.1 and master ### Operating System tested linux and Windows